RT420. GPS-Based Time Reference. Reference Manual

RT420 GPS-Based Time Reference Reference Manual

Reason Tecnologia S.A. Rua Delminda Silveira, 855 88025-500 Florianópolis, SC Brasil Fone: (48) 2108-0300 Fax: (48) 2108-0310 http://www.reason.com.br Reason International, Inc. 7101 W Highway 71 Austin, TX 78735 USA Phone: (512) 615-0490 Fax: (512) 615-0491 http://www.reason-international.com Reason Europe GmbH i. G. Ascherslebener Strae 3 D-06333 Hettstedt Deutschland Telefon: +49 (0)3476 559345 Fax: +49 (0)3476 559286 http://www.reason-europe.com Applicable models: P025-Axx/1 P025-Axx/2 P025-Axx/4 P025-Axx/5 P025-Axx/6 P025-Axx/7 Firmware version: 08Axx Document Id: rt420-manual-en Revision: 4.1 c 2008, 2009 Reason Tecnologia S.A. All rights reserved. Products developed by REASON are continuously improved and the associated technical documentation is frequently updated. Please make sure you have the latest release of this document before proceeding. All specifications are subject to change without prior notice. DIN EN ISO 9001 Reason is committed to quality. Certification to the CE and the ISO 9001:2000 quality standard are examples of this commitment. We encourage and appreciate any feedback and will use it to improve our products and services.

Contents Contents i 1 Safety Instructions 1 1.1 General Safety Instructions.................................. 1 1.2 Passwords and Remote Access................................ 1 1.3 Safety Symbols........................................ 1 2 Getting Started 3 2.1 Overview........................................... 3 2.2 Key Features......................................... 3 2.3 Unpacking........................................... 4 2.4 Serial Number and Part Number Location.......................... 4 2.5 Powering-Up......................................... 5 3 Specifications 7 3.1 GPS input........................................... 7 3.2 IRIG-B000 optical input (optional).............................. 7 3.3 Internal oscillator....................................... 7 3.4 TTL-level electrical outputs.................................. 7 3.5 Open-collector outputs.................................... 8 3.6 Optical outputs (optional)................................... 8 3.7 Amplitude-modulated outputs................................ 8 3.8 RS232 serial port....................................... 8 3.9 Ethernet port......................................... 8 3.10 LOCKED dry contact..................................... 9 3.11 Dimensions, weight...................................... 9 3.12 Power............................................. 9 3.13 Environmental......................................... 9 3.14 Type tests (EMC)....................................... 10 i

ii CONTENTS 3.15 Type tests (safety)....................................... 10 3.16 Type tests (environmental).................................. 10 3.17 Type tests (mechanical).................................... 10 4 Installation 11 4.1 Mounting........................................... 11 4.2 Environment.......................................... 11 4.3 Power Connection....................................... 11 4.4 Antenna............................................ 13 4.5 Antenna Cable Effects.................................... 14 4.6 Optical IRIG-B000 Input................................... 15 4.7 Optical Outputs........................................ 16 4.8 TTL-level Electrical Outputs................................. 16 4.9 Open Collector Outputs.................................... 17 4.10 Amplitude-Modulated Outputs................................ 18 4.11 RS232 Serial Port....................................... 18 4.12 Ethernet Port......................................... 19 4.13 Locked Dry Contact...................................... 19 5 Operation 21 5.1 Front Panel Indicators..................................... 21 5.2 Power-Up Sequence...................................... 22 5.3 Power-Down Sequence.................................... 22 6 Configuration 23 6.1 Overview........................................... 23 6.2 Protocols........................................... 23 6.3 Running TELNET from Windows.............................. 23 6.4 Running SSH......................................... 24 6.5 Authentication......................................... 24 6.6 Behavior during configuration................................ 24 6.7 Configuration Sequence.................................... 25 7 ASCII Commands 27 7.1 Command Format....................................... 27 7.2 Command History and Editing................................ 27 7.3 Command Reference..................................... 28

iii 8 Datagrams 53 8.1 ACEB............................................. 54 8.2 GPZDA............................................ 55 8.3 MEINBERG......................................... 56 9 Maintenance and Troubleshooting 57 9.1 Common Problems...................................... 57 9.2 Forgotten Password or Unknown Network Parameters.................... 58 9.3 CMOS Clock Battery Replacement.............................. 59 9.4 Returning a Unit....................................... 59 Part Numbers 61 Modbus Interface 63 Implementation........................................... 63 Message Format........................................... 63 Implemented Functions....................................... 63 Function 4 (Read Input Registers)................................. 64 Registers Map............................................ 65 Summary of IRIG-B Standard 69 IRIG-B000 and IRIG-B120 Contents................................ 69

1 Safety Instructions 1.1 General Safety Instructions Before attempting to install or use the equipment described in this manual, it is imperative that all DANGER and CAUTION warnings are reviewed to help prevent personal injury, equipment damage and/or downtime. This manual is intended for technically qualified personnel which has been trained or is knowledgeable in instrumentation and automation fields. This instruction manual is an integral part of the scope of delivery and provides basic instructions for installation, configuration, operation and maintenance of the equipment here described. Shall additional information be needed, please contact REASON at the addresses provided at the beginning of this document. 1.2 Passwords and Remote Access This equipment is delivered with factory-default passwords. This passwords should be changed by the user as part of equipment installation and initial configuration. Failure to do so may result in unauthorized access to the equipment. 1.3 Safety Symbols The following symbols are located on different parts of the units housing and in this manual. Paragraphs marked with this symbol contain information which, if not properly followed, may cause damage to the equipment and/or installation. Paragraphs marked with this symbol contain information which, if not properly followed, may cause personal injury or even death. Safety ground. 1

2 Getting Started 2.1 Overview RT420 provides time, frequency and phase reference signals via configurable electrical, optical and logical output ports. Time information is provided by a built-in GPS receiver or an external IRIG-B000 source. Time information is shown on a display and output in a variety of formats including a DC-shift and amplitude-modulated IRIG-B signal, RS232C serial datagrams, and several types of time pulses. Accuracy of the internal time-base is better than 100 ns (1 sigma). The RT420 time reference is able to produce time information referred to UTC or to a local time-zone. Support for Daylight Saving Time is also provided. The unit is intended for 19-inch rack-mounting and can be powered from a wide range of AC and DC power sources. RT420 front and back views 2.2 Key Features 100 ns (1 sigma) maximum time deviation Built-in NTP and SNTP servers using 10/100Base-T Ethernet port 3

2. GETTING STARTED IRIG-B000 and IRIG-B120 time codes 100 pulses-per-second, 1 pulse-per-second, 1 pulse-per-minute signals Freely configurable low frequency pulse generator from 1 pulse-every-two-seconds to 1 pulse-every- 24-hours Pulse-on-time and pulse-on-date signals (daily repetition or not) 8 optical fiber outputs (optional) 8 TTL-level electrical outputs, normal or inverted polarity 3 open-collector outputs, normal or inverted polarity 2 IRIG-B120 outputs modulated in amplitude RS232 serial port with PPS signal (normal or inverted polarity), freely configurable messages Status monitoring using SNMP or Modbus Locked dry contact for remote signalling User-configurable rules for daylight-saving-time (DST) Uses GPS satellites or external IRIG-B000 (optional) as time basis Time delay compensation for antenna cables and optical-fiber cables Configurable over Ethernet using SSH or TELNET protocols 2.3 Unpacking Unpack the unit carefully and make sure that all accessories and cables are put aside so they will not be lost. Check the contents against the packing list. If any of the contents listed are missing, please contact REASON immediately (see contact information at the beginning of this manual). Examine the unit for any shipping damage. If the unit is damaged or fails to operate, notify the shipping company without delay. Only the consignee (the person or company receiving the unit) can file a claim against the carrier for shipping damage. We recommend that you retain the original packing materials for use should you transport or ship the unit in the future. 2.4 Serial Number and Part Number Location The unit s serial number and part number are engraved on a small nameplate, located on the unit s right side, near the MAINS terminal. Serial number and part number location For information about how to interpret the part number, refer to page 61. 4

Powering-Up 2.5 Powering-Up 1. Be sure you are familiar with all appropriate DANGER and CAUTION warnings in this manual. 2. Refer to Chapter 4 for detailed mounting and wiring instructions. Do not operate the unit without the safety ground connection in place. 3. Make sure the power switch at the back of the unit is in the OFF position. 4. [OPTIONAL] Connect a GPS antenna to the unit. Refer to section 4.4 for further information about antenna positioning and requirements. 5. Connect power to the unit. The MAINS indicator on the unit s front panel will light immediately. 6. Power on the unit using the switch on the back panel. 7. A self-test will be executed, blinking all indicators except MAINS on the front panel twice. 8. The unit will now initialize the internal time-references, including the GPS receiver. This will take up to one minute. Progress is indicated by successively lighting up the segments of the time display on the front panel. 9. As soon as initialization is complete, the READY indicator will light up and the internal time will be displayed on the front panel. 10. If an antenna is connected to the unit, the LOCKED indicator will start blinking after a few minutes, indicating that the time produced by the unit is being derived from the GPS satellites. The LOCKED indicator will stop blinking and stay on once full accuracy is achieved. 1 A clear line-of-sight from the antenna to at least 4 GPS satellites is required for the unit to enter the locked state. 11. Factory defaults for Ethernet port are listed below. IP address 192.168.0.199 Network mask 255.255.255.0 Broadcast address 192.168.0.255 Gateway address 192.168.0.1 Password cond3e89 Should this parameters not be appropriate for the installation, use a cross-over Ethernet cable to connect the unit to a computer and change the parameters as needed with the ETHER command (refer to page 35 for further details). 12. Shall the unit fail to operate as described, carefully review the power and all signal connections. Refer to Chapter 9 for further help on troubleshooting. 13. To switch the unit off, flip the power switch to the OFF position. The unit will record date, time, satellite almanach and internal drift estimates in non-volatile memory so as to increase accuracy and reduce locking time at the next power up. After recording is finished, all indicators except MAINS on the front panel will be turned off. 1 This may take up to the 12 minutes if the unit has been moved over great distance since last powered off or if the unit has been off for several weeks. 5

3 Specifications 3.1 GPS input Signal GPS L1 (1575.42 MHz), C/A code Number of channels 12 Antenna type active Antenna power 3.3 V, max 100 ma Input impedance 50 Ω Connector type BNC (female) Sensitivity -152 dbm (tracking) -142 dbm (acquisition) 3.2 IRIG-B000 optical input (optional) Signal Wavelength Fiber type Connector type Sensitivity IRIG-B000 (with IEEE C37.118 CF extensions) 820 nm 50/125 µm, 62.5/125 µm, 100/140 µm or 200 µm HCS multimode ST 24 dbm 3.3 Internal oscillator Drift (free run) < 1 ppm (10 6 ) Time error (free run) < 100 ms per day 3.4 TTL-level electrical outputs Signals High level voltage Low level voltage Maximum current Output impedance IRIG-B000 (with IEEE C37.118 CF extensions), 1PPS, 100PPS, 1PPM, low frequency pulses (from 1 pulseevery-two-seconds to 1 pulse-every-24-hours), pulse-ontime and pulse-on-date > 4 V < 0.2 V 80 ma 15 Ω 7

3. SPECIFICATIONS 3.5 Open-collector outputs Signals Maximum collector-emitter voltage Maximum current IRIG-B000 (with IEEE C37.118 CF extensions), 1PPS, 100PPS, 1PPM, low frequency pulses (from 1 pulseevery-two-seconds to 1 pulse-every-24-hours), pulse on time and pulse on date 150 V 200 ma 3.6 Optical outputs (optional) Signal Wavelength Fiber type Connector type Output power (typical) IRIG-B000 (with IEEE C37.118 CF extensions) 820 nm 50/125 µm, 62.5/125 µm, 100/140 µm or 200 µm HCS multimode ST 17.8 dbm (50/125 µm) 14.0 dbm (62.5/125 µm) 8.5 dbm (100/140 µm) 5.7 dbm (200 µm HCS) 3.7 Amplitude-modulated outputs Signal IRIG-B120 (with IEEE C37.118 CF extensions) No-load voltage 4 Vpp Voltage with 50 Ω load 3 Vpp High/low amplitude ratio 3.33 Carrier frequency 1 khz Output impedance 15 Ω Connector type BNC (female) 3.8 RS232 serial port Signal level RS232 Bitrate 1200, 2400, 4800, 9600, 19200 or 38400 bps Databits 7 or 8 Stopbits 1 or 2 Parity none, even, odd Connector type DB9 (male), DTE layout 3.9 Ethernet port Data rate 10 / 100 Mbps Connector type RJ 45 Protocols NTP, SNTP, SNMP, Modbus, SSH, TELNET 8

LOCKED dry contact 3.10 LOCKED dry contact Rating 300 ma @ 250 Vdc 1000 ma @ 125 Vdc 3.11 Dimensions, weight Height Width (body) Depth Weight 1 U 430 mm (16.9 in) 180 mm (7.1 in) 2.7 kg (5.9 lbs) 3.12 Power Rated operating voltage Input voltage range Frequency Power consumption 100 250 Vdc, 110 240 Vac 80 275 Vdc, 88 264 Vac 50/60 Hz ±3 Hz < 15 VA (AC) 3.13 Environmental Temperature range (recommended) +5...+55 C (+41...+131 F) Temperature range (tested) 25...+70 C ( 13...+158 F) Enclosure protection IP40 Maximum altitude 2000 m (6560 ft) Relative humidity 5... 95%, noncondensing 9

3. SPECIFICATIONS 3.14 Type tests (EMC) IEC 61000-4-2 Electrostatic discharge 6 kv (contact), 8 kv (air) IEC 60255-22-2 IEC 61000-4-3 Radiated RF immunity 10 V/m IEC 60255-22-3 IEC 61000-4-4 Burst 2 kv IEC 60255-22-4 IEC 61000-4-5 Surge 2 kv (common mode) IEC 60255-22-5 1 kv (diferential mode) IEC 61000-4-6 Conducted RF immunity 10 V IEC 60255-22-6 IEC 61000-4-8 Magnetic field immunity 30 A/m IEC 61000-4-11 Voltage dips 0 % during 0.5 cycles, 0 and 180 degrees 0 % during 1 cycle 40 % during 10/12 cycles 70 % during 25/30 cycles 80 % during 250/300 cycles IEC 60255-22-1 Burst 1 MHz 2.5 kv (common mode) 1 kv (differential mode) IEC 60255-25 Conducted RF emission 0.15 MHz to 0.5 MHz: 79 db / 66 db CISPR-22 0.5 MHz to 30 MHz: 73 db / 60 db Radiated RF emission 30 MHz to 230 MHz: 40 db 230 MHz to 1000 MHz: 47 db 3.15 Type tests (safety) IEC 60255-5 Dielectric test 2.8 kvdc @ 1 min 5 kv impulse Insulation resistance > 100 MΩ @ 500 VDC IEC 61010-1 Safety tests 3.16 Type tests (environmental) IEC 60068-2-1 Cold 25 C, 16 hours, 1 cycle IEC 60068-2-2 Dry heat +70 C, 16 hourss, 1 cycle IEC 60068-2-14 Change of temperature 25 C...+70 C, 9 hours, 2 cycles IEC 60068-2-30 Damp heat +55 C, 95 %, 12+12 hours, 1 cycle 3.17 Type tests (mechanical) IEC 60068-2-6 Vibration (sinusoidal) 0.035 mm, 0.5 g, 1 cycle on each axis IEC 60255-21-1 1 g, 20 cycles on each axis IEC 60068-2-27 Shock 15 g, 11 ms, 3 pulses on each face IEC 60255-21-2 10

4 Installation Please refer to the figure below throughout this chapter. RT420 back view 4.1 Mounting RT420 has been designed to be mounted in a standard 19-inch rack by means of four M6x15 screws. Allow adequate clearance for all connections. Do not bend the antenna cable excessively since this might alter its impedance, degrading the units performance. 4.2 Environment Temperatures inside the rack should not not exceed the limits stated in section 3.13. Appropriate heating or cooling measures must be provided to guarantee that this requirement is met at all times. Air humidity should respect the limits described in section 3.13. 4.3 Power Connection The unit can be powered from DC or AC power within the limits specified in section 3.12. All power connections should use insulated flexible cable with a 1.5 mm 2 cross section attached to the supplied header connector. To reduce the risk of electrical shock, pre-insulated pin terminals should be uses on the ends of the power connections. 11

4. INSTALLATION Pre-insulated pin terminals The pin terminals should be completely inserted into the header connector supplied with the unit so that no metallic parts are exposed. Refer to the figure below. Header connector assembly A safety ground lead shall be connected to the terminal marked with the protective earth symbol. For better electromagnetic compatibility, ground the unit using a 10 mm (0.4 in) wide grounding strap to connect the rear panel of the unit to a good ground point on the mounting rack. AC Power Connection Phase should be applied to terminal 1, neutral to terminal 2. AC power connection Installation of an external 10 A, category C, unipolar circuit-breaker near the unit is recommended. The circuit breaker should have an interruption capacity of at least 25 ka and comply to IEC 60947-2. 12

Antenna DC Power Connection Positive should be applied to terminal 1, negative to terminal 2. DC power connection Installation of an external 10 A, category C, bipolar circuit-breaker near the unit is recommended. The circuit breaker should have an interruption capacity of at least 25 ka and comply to IEC 60947-2. 4.4 Antenna A 3.3-Volt active GPS antenna (100 ma max) must be connected to the ANTENNA terminal if GPS satellites are to be used as time reference. Refer to section 3.1 for additional information. There is no need to connect an antenna if the unit is to be operated as a time repeater. In this case, the optical IRIG-B000 shall be used (refer to section 4.6 for further information). Antenna connector The antenna must be mounted outdoors, in a vertical position, with an unobstructed view of the sky. The antenna should be placed above the height of the building as much as possible. A partially obstructed sky view will degrade the units performance. The antenna should not be located under overhead power lines or other electric light or power circuits, or where it can fall into such power lines or circuits. An antenna mast or roof-mounting-kit and any supporting structure must be properly grounded to provide protection against voltage surges and built-up static charges. The antenna has to be connected to the unit using a coaxial cable with a 50 Ω impedance. The antena cable should be routed trough a conduit, shielded from rain and solar radiation. The conduit should not be shared with any power cabling. Cables with lengths ranging from 15 m (50 ft) to 100 m (328 ft) are available from REASON. Contact 13

4. INSTALLATION REASON for further information on using third-party antennas and cables. 4.5 Antenna Cable Effects The GPS signal is attenuated before reaching the RT420 antenna input. If the attenuation is excessive, the signal strength may not be sufficient to lock to the GPS satellites. The GPS signal is also slightly delayed. If the ultimate time accuracy is desired, this delay should be compensated inside the unit. Attenuation GPS signal attenuation is a function of cable type and overall cable length. When using the active antenna supplied by REASON, total attenuation should not exceed 32 db. Total attenuation can be computed using A = A u l where A u is the attenuation per unit length for the given cable and l is the overall cable length. The table below shows a few typical cable configurations and the associated total attenuation. Cable Length RGC58 cable RGC8 cable 15 m (50 ft) 7 db 25 m (82 ft) 12 db 50 m (164 ft) 23 db 75 m (246 ft) 12 db 100 m (328 ft) 17 db 125 m (410 ft) 21 db 150 m (492 ft) 25 db Propagation Delay The cable delays the GPS signal. If the ultimate time accuracy is desired, this delay has be compensated inside the unit. Typically, the delay introduced by coaxial cables is in the magnitude of 4 ns/m (1.2 ns/ft) of cable length. The exact delay can be computed by T = 1 CK v l where C = 3 10 8 m/s is the light speed, K v = 0.8 to 0.85 is a constant which depends on the cable and l is the cable length in meters. The table below summarizes some typical delays introduced by coaxial cables 14

Optical IRIG-B000 Input Cable Length Typical Delay 15 m (50 ft) 60 ns 25 m (82 ft) 100 ns 50 m (164 ft) 200 ns 75 m (246 ft) 300 ns 100 m (328 ft) 400 ns 125 m (410 ft) 500 ns 150 m (492 ft) 600 ns Delays of up to 10 µs can be compensated with the DELAY ASCII command (see page 32). 4.6 Optical IRIG-B000 Input The IRIG-B000 optical input should be used when the unit is operated as a time repeater. There is no need to use this input if the unit is to be operated using GPS sattelites in which case the ANTENNA input should be used instead (refer to section 4.4 for further information). The optical IRIG-B000 is not available on all RT420 models. Please refer to the unit s part number to find out if the model you are using supports this feature. Further information on how to interpret the part number can be found on page 61. Optical IRIG-B000 input For correct operation, the IRIG-B000 signal applied to this input should use the Control Field extensions as defined in the IEEE C37.118 Standard. Particularly, the time-offset information is needed to convert local time to UTC. Propagation Delay The optical fiber cable used to carry the IRIG-B000 signal to the RT420 introduces a significant delay. If the ultimate time accuracy is desired, this delay has be compensated inside the unit. Typically, the delay introduced by multimode optical fiber cables is in the magnitude of 5 to 6 ns/m (1.5 to 1.8 ns/ft). The following table summarizes some typical optical cable delays 15

4. INSTALLATION Optical Fiber Length Typical Delay 100 m (328 ft) 500... 600 ns 250 m (820 ft) 1.25... 1.50 µs 500 m (1640 ft) 2.50... 3.00 µs 750 m (2460 ft) 3.75... 4.50 µs 1000 m (3280 ft) 5.00... 6.00 µs 1250 m (4100 ft) 6.25... 7.50 µs 1500 m (4920 ft) 7.50... 9.00 µs Delays of up to 10 µs can be compensated with the DELAY ASCII command (see page 32). 4.7 Optical Outputs The optical outputs are not available on all RT420 configurations. Please refer to the unit s part number to find out if the model you are using supports this feature. Further information on how to interpret the part number can be found on page 61. Optical outputs The signal present at this outputs is IRIG-B000 with CF extensions according to the IEEE C37.118 Standard. 4.8 TTL-level Electrical Outputs Length of cables connected to this outputs should not exceed 5 m (16 ft). Refer to section 3.4 for signal levels and maximum load information. TTL-level electrical outputs The type of signal at each output can be configured with the OUTPUT command (page 40). Options include IRIG-B000, 1PPS, 1PPM, 100PPS, a custom-defined low frequency, pulse-on-time and pulse-on-date. 16

Open Collector Outputs The polarity of the signal at each output can be individually configured with the POLARITY command (page 42). For the 1PPS, 1PPM, custom-defined low-frequency, pulse-on-time and pulse-on-date signals, the width of the pulse can be configured with the WIDTH command (page 51). 4.9 Open Collector Outputs Length of cables connected to this outputs should not exceed 5 m (16 ft). Refer to section 3.5 for signal levels and maximum load information. Open-collector outputs The type of signal at each output can be configured with the OUTPUT command (page 40). Options include IRIG-B000, 1PPS, 1PPM, 100PPS, a custom-defined low frequency, pulse-on-time and pulse-on-date. The polarity of the signal at each output can be individually configured with the POLARITY command (page 42). For the 1PPS, 1PPM, custom-defined low-frequency, pulse-on-time and pulse-on-date signals, the width of the pulse can be configured with the WIDTH command (page 51). The open-collector outputs are unfused and require an external resistor to limit the current that circulates through the transistors. The resistor s value can be computed by R c V c 0.2 where V c is the voltage being switched by the transistor. The power rating of the resistor has to be adequate for the voltage and current applied and can be computed by P c 1.2 V c 2 R c Do not connect the open-collector outputs without limiting the current with an external resistor. Failure to do so will result in damage to this outputs. 17

4. INSTALLATION 4.10 Amplitude-Modulated Outputs Use coaxial cables with an impedance of 50 Ω and BNC on this outputs. Refer to section 3.7 for signal levels. Amplitude-modulated outputs Signal at this outputs is IRIG-B120 with CF extensions according to the IEEE C37.118 Standard. 4.11 RS232 Serial Port This is a DB9 male connector with a DTE pin-layout. RS232 serial port The bitrate and format (number of data bits, parity, number of stop bits) of the characters sent out of this port can be configured with the SERIAL command (page 44). Several built-in datagrams can be selected with the DATAGRAM command (page 30) or a custom-defined one can be configured with the ASCII-DATAGRAM command (page 29). A one pulse-per-second pin is also provided. Polarity of the PPS signal can be configured with the PO- LARITY command (page 42) and the pulse width can be adjusted with the WIDTH command (page 51). 18

Ethernet Port 4.12 Ethernet Port Connect a CAT5 cable with an RJ45 connector to the Ethernet port. The LINK led indicates that the cable is live and the ACTIVITY led blinks when there is a data exchange. Ethernet port Use the ETHER command (page 35) to configure the IP address, the network mask and the broadcast and gateway addresses. 4.13 Locked Dry Contact This dry contact can be used for remotely signaling the LOCKED state of the unit. Length of cables connected to this terminals should not exceed 5 m (16 ft). Refer to section 3.10 for information on load switching limitations. Locked dry contact 19

5 Operation 5.1 Front Panel Indicators RT420 front panel The RT420 s front panel has a time display, three green status indicators and three red alarm indicators. Time Display The time display always shows local time in a 24 hour format. If no valid time is available the display will show : :. This situation occurs during the unit s initialization, during a configuration session or if the internal CMOS clock battery is exhausted. The time display might also briefly display : : when locking to GPS satellites or an external IRIG-B000 time reference if a time-step occurs. Status Indicators (Green) These section comprises three indicators. The MAINS indicator is lit whenever power is applied to the unit, even when it is switched off. The READY indicator is lit as soon as the unit has completed its internal initialization. The LOCKED indicator is lit when the unit has locked to an external time-reference (GPS satellites or IRIG-B000 optical input). It blinks while downloading almanach data from GPS satellites. 1 It goes off soon after the external reference is lost. There is a LOCKED dry contact on the unit s back panel that closes once full accuracy is achieved. Alarm Indicators (Red) These section also comprises three indicators. The ANTENNA SHORT indicator lits up if the power consumption on the ANTENNA connector exceeds 150 ma. This is normally associated with a short-circuit on the antenna itself, one of the connectors or the 1 This is only noticed if the unit has been moved over great distance since last powered off or if it has been off for several weeks. 21

5. OPERATION coaxial cable leading up to the antenna. This indicator is blanked out when the IRIG-B000 optical input is used as a time reference. The ANTENNA OPEN indicator lits up when no current is drawn from the ANTENNA connector on the unit s back panel. This is the case when no antenna is connected or if the cable leading up to the antenna is broken. This indicator is blanked out when the IRIG-B000 optical input is used as a time reference. The ALARM indicator lits up during power-up when the internal CMOS clock battery is exhausted. Refer to Chapter 9 for instructions on replacing the battery. As a workaround until the battery is replaced, the command DATE can be used to allow the initialization to proceed. 5.2 Power-Up Sequence The MAINS indicator is lit as soon as power is applied to the unit. After switching the unit on, a brief self-test will be executed, blinking all indicators (except MAINS) on the front panel twice. The unit will now initialize the internal time-references, including the GPS receiver. This will take up to one minute. Progress is indicated by successively lighting up the segments of the time display on the front panel. As soon as initialization is complete, the READY indicator will lit up and the internal time will be displayed on the front panel. If the initialization fails, the time display will show Error. In this case, refer to Chapter 9 for further help. If the internal CMOS clock battery is exhausted, the ALARM indicator will lit up and the time display will show : :. The unit will only proceed on the power-up sequence after date and time are manually entered with the DATE command. Refer to Chapter 9 for instructions on how to replace the battery. If an antenna is connected to the unit, the LOCKED indicator will start blinking after a few minutes, indicating that the time produced by the unit is being derived from the GPS satellites. The LOCKED indicator will stop blinking and stay on once full accuracy is achieved. This may take up to the 12 minutes if the unit has been moved over great distance since last power off or if the unit has been off for a very long time. A clear line-of-sight from the antenna to at least 4 GPS satellites is required for the unit to enter the locked state. Alternatively, the LOCKED indicator will lit soon after a valid signal is applied to the IRIG-B000 optical input and the TIME-REFERENCE IRIGB command is issued to the unit. 5.3 Power-Down Sequence After the power switch is turned to the OFF position, the unit will record date, time, satellite almanach and internal drift estimates in non-volatile memory so as to increase accuracy and reduce locking time at the next power up. After recording is finished, all indicators except MAINS on the front panel will be turned off. 22

6 Configuration 6.1 Overview Configuration is performed using the Ethernet port. Factory defaults for this port are: IP address 192.168.0.199 Network mask 255.255.255.0 Broadcast address 192.168.0.255 Gateway address 192.168.0.1 Password cond3e89 6.2 Protocols The ASCII commands described in this chapter can be used over the SSH protocol (Secure SHell protocol) (port 22) or over the TELNET protocol (port 23). If there is a choice, the SSH protocol should be used since it is much more secure than the TELNET protocol. The TELNET protocol can be disabled with the TELNET OFF ASCII command (refer to page 46 for further details). 6.3 Running TELNET from Windows Windows 95, 98, ME, NT, 2000, or XP To access Microsoft Telnet from Windows 95, Windows 98, Windows ME, Windows NT, Windows 2000, or Windows XP, click START,RUN, then type telnet ip where ip is the ip address of the RT420 you want to access. Then press ENTER. Some setups of Microsoft Windows may prohibit users from running the telnet command. Check with your system administrator if you are unable to open the program. Windows Vista By default, Telnet is not installed with Windows Vista. It can be installed by following the steps below. 23

6. CONFIGURATION 1. Click the Start button, click Control panel, click Programs, and then click Turn Windows features on or off. If you are prompted for an administrator password or confirmation, type the password or provide confirmation. 2. In the Windows Features dialog box, select the Telnet Client check box. 3. Click OK. The installation might take several minutes. 6.4 Running SSH SSH clients are built-in in Linux, Unix and MacOS. PUTTY is a free, open source SSH client for Windows, Linux, and Unix. TERATERM is another free SSH client for Windows. Please contact REASON for help in selecting and installing a SSH client for Windows. 6.5 Authentication The equipment configuration is protected by a username and a password. The factory default settings are: username password configuration cond3e89 The password can (and should) be changed with PASSWD ASCII command (refer to page 41 for further details). The default password can be restored by pressing and holding the RST button for at least 2 seconds. The RST button is located on the unit s back panel, near the Ethernet port. To reach the button, use a small screwdriver, a paper clip straightened out or similar object with a diameter less than 1 mm (0.04 in). Please note that, apart from restoring the default password, the RST button will also reset the network configuration (IP address, network mask, broadcast and gateway addresses) and also re-enable the TELNET protocol. After passing authentication, the user will be greeted with a message stating the date and time of the last configuration session and the IP address of the computer from where it was started. Last login: Fri Feb 8 10:13:11 2008 from 192.168.0.23 Type HELP for help. > 6.6 Behavior during configuration The following events will occur during the configuration: TTL-level, open collector and optical outputs stop sending data at the next second roll-over the RS232 serial port will stop sending datagrams after the current one has been sent the internal NTP server will stop responding to connection attempts front panel time display will show : : the LOCKED relay will open, the LOCKED indicator on the front panel goes out 24

Configuration Sequence the READY indicator on the front panel stays lit The following actions will take place after ending the configuration session with the EXIT command (page 36) TTL-level, open collector and optical outputs start sending data at the next second roll-over the RS232 serial port starts sending datagrams the internal NTP server accepts connections front panel time display shows actual local time the LOCKED relay will close and the LOCKED indicator on the front panel will lit as soon as the required conditions are met 6.7 Configuration Sequence This section describes the steps required to configure a RT420. It is suggested that the configuration be performed in the sequence described below. The configuration uses the ASCII commands described in Chapter 7. 1. Communication a) Use the ETHER command (page 35) to set the required IP address, network mask, broadcast and gateway addresses. b) Decide if the TELNET protocol is required. If it is not required, it should be disabled for safety reasons with the TELNET OFF command (page 46). c) Change the factory-default password with the PASSWD command (page 41). 2. Time Zone and Daylight Saving Time a) Use the TZ command (page 49) to set the timezone. b) Decide if Daylight Saving Time rules should be enabled and use the DST command (page 34) to configure them. DST rules are disabled by default. 3. Time Reference a) The unis is set by default to use GPS satellites as a time reference. In this case no action from the user is required since this is the default. If the unit is being operated as a time repeater use the TIME-REFERENCE IRIGB command (page 47) to select the IRIG-B000 optical input. b) The best possible accuracy is obtained when using the DELAY command (page 32) to specify the cable delay (antenna cable or optical fiber) to be internally compensated. Typical propagation delay times for antenna cables and optical fibers are listed on pages 14 and 15 respectively. 4. TTL-level outputs a) Decide which signal is desired at each of the TTL-level outputs and use the OUTPUT command (page 40) to select it. b) If a pulse-on-time or a pulse-on-date is desired, use the TMARK and DMARK commands (respectively described on pages 48 and 33) to configure the unit accordingly. c) If a low-frequency pulse is desired, use the PPX command (page 43) to select the required frequency. d) Use the POLARITY command (page 42) if needed. e) Adjust the pulse width with the WIDTH command (page 51) if needed. 25

6. CONFIGURATION 5. Open-collector outputs a) Decide which signal is desired at each of the open-collector outputs and use the OUTPUT command (page 40) to select it. b) If a pulse-on-time or a pulse-on-date is desired, use the TMARK and DMARK commands (respectively described on pages 48 and 33) to configure the unit accordingly. c) If a low-frequency pulse is desired, use the PPX command (page 43) to select the required frequency. d) Use the POLARITY command (page 42) if needed. e) Adjust the pulse width with the WIDTH command (page 51) if needed. 6. RS232 serial port a) Select one of the built-in datagrams with the DATAGRAM command (page 30). If none of the built-in datagrams is adequate for the application, use the ASCII-DATAGRAM command (page 29) to define a datagram and then issue the DATAGRAM ASCII command. b) Use the SERIAL command (page 44 to configure bitrate, number of data bits, parity and number of stop-bits. c) Use the HOLD command (page 37) to configure at which precise time after (or before) the second rollover the message will be sent. d) If the PPS pin on the serial port is used, its polarity and pulse width can be configured with the POLARITY and WIDTH commands (respectively pages 42 and 51). 26

7 ASCII Commands 7.1 Command Format ASCII commands must be all uppercase or all lowercase. Mixed upper and lowercase commands are not recognized. If an ASCII command is entered without any parameters, a short usage message will be returned followed by the current configuration for that command. When using parameters, all of them must be entered in the specified sequence. If an invalid or out-of-range parameter is entered, a Invalid parameter: followed by the offending text will be issued. Similarly, if an unknown command is entered, a command not found message will be issued. 7.2 Command History and Editing Durign a configuration session, the last commands issued by the user can be retrieved with the up and down keys. Once retrieved, a command can be edited by moving the cursor with the left and right keys and inserting and deleting new characters as appropriate. 27

7. ASCII COMMANDS 7.3 Command Reference ASCII-DATAGRAM DATAGRAM DATE DELAY DMARK DST ETHER EXIT HELP HOLD NTP-OFFSET OUTPUT PASSWD POLARITY PPX SERIAL SHOW TELNET TMARK TIME-REFERENCE TZ VERSION WIDTH ASCII datagram definition selection of datagram to be sent over serial port adjusts date and time of internal CMOS clock cable delay compensation configures date and time for pulse-on-date Daylight-Saving-Time rules configuration network parameters configuration closes configuration session lists all available commands with a short description configures hold-time for serial port messages adjusts the time reported by the NTP server configures signal present at TTL-level and open collector outputs password change configuration of TTL-level and open collector outputs polarity low frequency generator configuration RS232 serial port parameters shows current configuration enables / disables TELNET protocol configures time for pulse-on-time selects GPS or IRIGB time reference timezone configuration reports firmware version configuration of TTL-level and open collector outputs pulse width 28

Command Reference ASCII-DATAGRAM Description Allows the definition of the ASCII datagram which will be sent out of the RS232 serial port once per second. Syntax ASCII-DATAGRAM string Where string is the definition of the datagram comprising literal characters and escapesequences for time and date-related parameters. Below is a list of the escape-sequences and the values returned. Escape-sequence Values Description %H 00... 23 hours %M 00... 59 minutes %S 00... 59 seconds %j 001... 366 day-of-year %d 01... 31 day-of-month %m 01... 12 month %y 00... 99 year (two last digits) %Y 2000... 2099 year (four digits) %u 1... 7 day-of-week (1 = Monday) %w 0... 6 day-of-week (0 = Sunday) %s S or DST ( S if Daylight-Saving-Time, otherwise) %o or # status ( if locked, # otherwise) %O or * status ( if locked, * otherwise) %Q or? status ( if locked,? otherwise) %1 <SOH> start-of-header (ASCII 01) %2 <STX> start-of-text (ASCII 02) %3 <ETX> end-of-text (ASCII 03) %4 <LF> line feed (ASCII 10) %5 <CR> carriage return (ASCII 13) %x checksum type 1 %% % % character (ASCII 37) is the blank space character (ASCII 32). Checksum type 1 consists two hexadecimal characters representing the XOR operation of all characters between a $ and * (the $ and the * are not included in the checksum). Useful for NMEA-type datagrams. Example ASCII-DATAGRAM Day:%d;Mes:%m;Year:%Y;Hour:%H;Minute:%M;Second:%S;;%3 29

7. ASCII COMMANDS DATAGRAM Description Selects which datagram will be sent out of the RS232 serial port. The choices are any of the built-in datagrams (refer to Chapter 8) or the custom defined ASCII-datagram (refer to command ASCII-DATAGRAM). Syntax DATAGRAM type type ASCII selects datagram defined by ASCII-DATAGRAM ACEB selects built-in ACEB datagram GPZDA selects built-in GPZDA datagram MEINBERG selects built-in Meinberg datagram Example DATAGRAM ASCII DATAGRAM GPZDA 30

Command Reference DATE Description This ASCII command sets date and time on the internal CMOS clock. This command only has to be issued if the date and time information in the CMOS clock has been corrupted by, for example, a weak battery. Date and time should be informed in local time, as specified by the TZ and DST commands. Syntax DATE yyyy-mmm-dd hh:mm:ss yyyy 2000... 2099 year mmm Jan... Dec month dd 01... 31 day hh 00... 23 hour mm 00... 59 minute ss 00... 59 second Example DATE 2008-Feb-19 14:53:15 31

7. ASCII COMMANDS DELAY Description Selects cable delay compensation. The command can be used to compensate GPS antenna cable propagation delays and IRIG-B000 optical fiber propagation delays. Syntax DELAY nanoseconds nanoseconds 0 to 10000 ns (50 ns steps) Example DELAY 1400 DELAY 200 32

Command Reference DMARK Description Sets date and time for pulse-on-date. Syntax DMARK yyyy-mmm-dd hh:mm:ss yyyy 2000... 2099 year mmm Jan... Dec month dd 01... 31 day hh 00... 23 hour mm 00... 59 minute ss 00... 59 second Example DMARK 2008-Mar-01 12:53:45 33

7. ASCII COMMANDS DST Description Configures Daylight-Saving-Time rules. Can also be used to turn DST rules off. Syntax DST BEGIN hh:mm wday month END hh:mm wday month hh:mm 00:00... 23:59 time of DST start / end wday firstsun first Sunday secondsat second Saturday lastfri last Friday month Jan... Dec month DST OFF Example DST OFF DST BEGIN 00:00 lastsat Oct END 01:00 thirdsat Feb 34

Command Reference ETHER Description Configures network parameters Syntax ETHER ip mask broadcast gateway ip mask broadcast gateway IP address network mask broadcast address gateway address Example ETHER 192.168.20.170 255.255.255.0 192.168.20.255 192.168.20.1 35

7. ASCII COMMANDS EXIT Description Closes configuration session. New configuration is applied and the units resumes generating time, frequency and phase signals. Syntax EXIT Example EXIT 36

Command Reference HOLD Description Configures hold time for the serial datagram. Time is relative to the second-rollover and can be positive (message is sent later than the second rollover) or negative (message is sent earlier than the second rollover). Syntax HOLD ms ms -999... 999 hold time in milliseconds Example HOLD 200 HOLD -120 37

7. ASCII COMMANDS HELP Description Prints list of all available ASCII commands. Syntax HELP Example HELP 38

Command Reference NTP-OFFSET Description Allows correction of values reported by the NTP server. Normally not needed, but can be used to compensate for systemic time differences. Syntax NTP-OFFSET milliseconds Example NTP-OFFSET 5 39

7. ASCII COMMANDS OUTPUT Description Selects the signal to be output at the TTL-level and open collector outputs. Factory default is a IRIG-B000 signal for the TTL-level outputs and no signal at the open collector outputs. Syntax OUTPUT output signal output TTL1... TTL8 TTL-level outputs OC1... OC3 open collector outputs signal OFF no signal IRIGB IRIG-B000 signal 100PPS 100 Hz square-wave 1PPS 1 pulse-per-second 1PPM 1 pulse-per-minute PPX low frequency pulse generator (refer to PPX ASCII command) TMARK pulse-on-time, repeated daily (refer to TMARK ASCII command) DMARK pulse-on-date, never repeated (refer to DMARK ASCII command) Example OUTPUT TTL1 1PPS OUTPUT TTL2 1PPM OUTPUT TTL3 PPX OUTPUT OC1 TMARK 40

Command Reference PASSWD Description Changes the access password. The new password has to be informed twice and is not shown during input. Syntax PASSWD Example PASSWD 3478bc 41

7. ASCII COMMANDS POLARITY Description Selects the polarity of signals at TTL-level, open-collector outputs and at the PPS-pin of the RS232 serial port. Factory default in normal (ie not-inverted) polarity at all outputs. Syntax POLARITY output polarity output TTL1... TTL8 TTL-level outputs OC1... OC3 open-collector outputs SERIAL PPS pin at RS232 serial port polarity + normal polarity - inverted polarity Example POLARITY TTL1 - POLARITY SERIAL - POLARITY OC2 + 42

Command Reference PPX Description Configuration of low frequency pulse generator. Values accepted range from one pulse everytwo-seconds to one pulse every-twenty-four-hours. Syntax PPX interval interval 2s, 3s, 4s, 5s, 6s, 10s, 12s, 15s, 60s 2m, 3m, 4m, 5m, 6m, 10m, 12m, 15m, 60m 2h, 3h, 4h, 6h, 8h, 12h, 24h Example PPX 5s PPX 60m 43

7. ASCII COMMANDS SERIAL Description Configuration of bitrate and format (number of data bits, parity, number of stop bits) for data sent out of the RS232 serial port. Syntax SERIAL speed data parity stop speed 1200... 38400 data 7 or 8 data bits parity none (N), even (E) or odd (O) stop 1 or 2 stop bits Example SERIAL 19200 8 N 1 SERIAL 1200 7 E 2 44

Command Reference SHOW Description Prints unit current configuration. Syntax SHOW Example SHOW 45

7. ASCII COMMANDS TELNET Description Enables / disables the TELNET protocol. Factory default is enabled. Syntax TELNET status status ON enables TELNET protocol OFF disables TELNET protocol Example TELNET OFF TELNET ON 46

Command Reference TIME-REFERENCE Description Selects time reference (GPS satellites or external IRIG-B000). Syntax TIME-REFERENCE source source GPS GPS satellites IRIGB IRIG-B000 optical input Example TIME-REFERENCE GPS TIME-REFERENCE IRIGB 47

7. ASCII COMMANDS TMARK Description Sets time for pulse-on-time. Pulse is repeated daily at the same time. Syntax TMARK hh:mm:ss hh 00... 23 hour mm 00... 59 minute ss 00... 59 second Example TMARK 18:53:46 48

Command Reference TZ Description Configures the timezone to be used when converting UTC time to local time. Note that halfhour time zones are supported. Syntax TZ hh:mm hh -12... 12 hours mm 00 or 30 minutes Example TZ -03:00 TZ -04:30 TZ 01:00 49

7. ASCII COMMANDS VERSION Description Prints version of installed firmware. Might be required when contacting product support. Syntax VERSION Example VERSION 50

Command Reference WIDTH Description Adjusts the pulse width for the 1PPS, 1PPM, PPX, TMARK and DMARK signals on the TTLlevel, open-collector outputs and the PPS pin on the RS232 serial port Factory default is 200 ms. Syntax WIDTH ms ms 10... 990 ms 10 ms steps Example WIDTH 250 WIDTH 500 51

8 Datagrams This chapter describes the built-in datagrams in alphabetical order. If the datagram needed is not described on the following pages, use the ASCII-DATAGRAM to define your own datagram or contact REASON for further support. Please note that the datagrams definition comprises only the message itself and the frequency at which it is sent. The bitrate and format of the characters can be configured using the SERIAL ASCII command (refer to page 44 for further information). The position of the on-time-mark characters can be configured using the HOLD ASCII command (refer to page 37 for further information). 53

8. DATAGRAMS 8.1 ACEB Comprises 13 bytes, sent once per minute at second 02. Byte Description Possible Values 1 Delimiter 0xFF 2 Header 0x01 3 Status 0x00 (locked) or 0x01 (not locked) 4 Start of transmission 0x02 5 Day of week BCD 01 (Monday)... BCD 07 (Sunday) 6 Year BCD 00... 99 7 Month BCD 01... 12 8 Day of month BCD 01... 31 9 Hour BCD 00... 23 10 Minute BCD 00... 59 11 Second BCD 02 12 End of transmission 0x03 13 Synchro byte 0x16 54

GPZDA 8.2 GPZDA Comprises 32 characters, sent once per second. $GPZDA,hhmmss.0,DD,MM,YYYY,,*CC<CR><LF> where Parameter Possible Values Description Remarks hh 00... 23 hours mm 00... 59 minutes ss 00... 59 seconds ddd 001... 366 day-of-year DD 01... 31 day-of-month MM 01... 12 month YYYY 2000... 2099 year (4 digits) Character ASCII ASCII Description (decimal) (hexadecimal) <LF> 10 0A line feed <CR> 13 0D carriage return Parameter Description Possible Values CC checksum two hexadecimal digits representing the result of the exclusive OR of all character between $ e * ( $ and * not included in the computation) 55