2070-6B Manual B Manual. Dual 9600 baud Modem For The 2070 Controller. GDI B Manual. Rev B

Transcription

1 2070-6B Manual B Manual Dual 9600 baud Modem For The 2070 Controller GDI B Manual Rev B This Manual covers Modems with the Serial numbers D and up.

2 2070-6B Manual 2 GDI B Manual Rev B This Manual covers Modems with the Serial numbers D and up. GDI COMMUNICATIONS, LLC 280 Interstate 80 Exit 1 PO Box 1330 Verdi, NV Phone (775) Fax (775)

3 2070-6B Manual 3 TABLE OF CONTENTS GENERAL DESCRIPTION... 4 SPECIFICATIONS... 4 INSTALLATION... 6 THEORY OF OPERATION 6 MAINTENANCE AND ADJUSTMENTS ADJUSTMENTS AMPLITUDE ADJUSTMENT FREQUENCY ADJUSTMENT SYMMETRY TROUBLESHOOTING... 12

4 2070-6B Manual 4 General Description The B Modem is a dual 9600 Baud FSK Modem for the 2070 Controller which utilizes the latest surface mount technology. The GDI B meets or exceeds the CALTRANS Transportation Electrical Equipment Specifications (TEES) of AUGUST 16, 2002 and applicable addendum. This Modem plugs into the A2 to A5 and A1 slots of the 2070 Controller and is held in place with two thumbscrews. The front panel has two M14 type connectors that are identical to the C2S and C20S connectors on the 170 Controllers. Therefore, cables made for the 300 series cabinets will work with the B. The B also converts the EIA-485 signals for SP1-4 on the backplane of the 2070 to EIA-232. These signals are available in the M14 (C2 and C20) connectors on the front panel if the Modem sections are not being used. A front panel switch can turn off each section of the Modem individually so that it doesn t interfere with the EIA-232 communication that might be going on. The front panel of the B also has Full Duplex/Half Duplex switches for each channel. A 5 th switch powers down the entire Module so that it can be inserted or taken out while the power to the 2070 is on. This prevents any of the parts on the B Modem or the 2070 Controller from being harmed during insertion or being unplugged. Six LEDs are also located on the front panel, 3 for each channel. They include Transmit Data (TX), Receive Data (RX), and Carrier Detect (CD). All of the RS-232 signals in the C2S and C20S connectors are optically isolated from the controller signals. The 5V supply and Ground in the C2S and C20S connectors are also isolated and individually fused at 200ma with a solid state PTC resettable to protect the 2070 s internal power supply. The B Module is built with surface mount parts for increased reliability and to reduce the parts count. The use of all surface mount parts has allowed us to put all of the parts on a single PC Board. The digital section and first modem are on the top side of the board. The second modem is on the back of the PC Board. Power and Ground planes prevent crosstalk and isolate the two modems from each other The GDI B also has an antistreaming option that can be selected with a dipswitch on the PC Board. Antisteaming will prevent a remote site from monopolizing the communication path in a multidrop configuration. Antistreaming is not normally used on the Master end. Separate switches also allow the timings on the handshake and modem control signals to be cut in half for faster communications. Specifications Each section of the Modem is identical and therefore these specifications apply both Modems. Physical.220mm x 177mm x 40.44mm. Temp..-37 to +74 degrees C.

5 2070-6B Manual 5 Humidity.5 to 95 % noncondensing. Power ma 150 ma 150ma Data Rate baud. Modulation.Phase Coherent FSK. Data Format Asynchronous, serial by bit Line interface..private Metallic wire 600 Ohm Mark Frequency 11,200 Hz +/- 1%. Space Frequency 17,600 Hz +/-1%. Soft Carrier 7,800 Hz +/- 1%. Receive Sensitivity.0 to -40 db. Output Level -8 to 10 db cont. Adj. (set to 0dB) CTS Delay /-2 ms. Rec. line Signal Detect Time...8 +/-2ms Receive Line Squelch.6.5 +/-1ms 0ms out. Soft Carrier Turnoff Time 10 +/-2ms. Modem Recovery Time.<22 ms. (ALL of these times can be cut in Half) Error Rate.<1 in 10 S/N of 16 db. Anti-streaming time-out.~5 sec. C2 and C20 Pinout Pin Function Pin Function A Audio In J RTS B Audio In K Data In (TXD) C Audio Out L Data Out (RXD) D +5 VDC M CTS E Audio Out N DC Gnd #1 F NA P NA H CD R NA 96 pin connector pin out for the B A2-5 Pin Assignments Pin A B C 1 SP1-TXD+ SP6TXD+ SP5TXD+ 2 SP1-TXD- SP6TXD- SP5TXD- 3 SP1-RXD+ SP6RXD+ SP5TXC+ 4 SP1-RXD- SP6RXD- SP5TXC- 5 SP1-RTS+ SP1- TXC(O)+ 6 SP1-RTS- SP1- TXC(O)- 7 SP1-CTS+ SP1- TXC(I)+ 8 SP1-CTS- SP1- TXC(1)- SP5RXD+ SP5RXD- SP5RXC+ SP5RXC- 9 SP1-DCD+ SP1-RXC+ SP3TXD+ 10 SP1-DCD- SP1-RXC- SP3TXD- 11 SP2-TXD+ SP4TXD+ SP3RXD+ 12 SP2-TXD- SP4TXD- SP3RXD- 13 SP2-RXD+ SP4RXD+ SP3RTS+ 14 SP2-RXD- SP4RXD- SP3RTS- 15 SP2-RTS+ SP2- TXC(O)+ 16 SP2-RTS- SP2- TXC(O)- 17 SP2-CTS+ SP2- TXC(I)+ 18 SP2-CTS- SP2- TXC(I)- SP3CTS+ SP3CTS- SP3DCD+ SP3DCD- 19 SP2-DCD+ SP2-RXC+ SP3TXCO+ 20 SP2-DCD- SP2-RXC- SP3TXCO- 21 DC Gnd #1 CH2 Disable SP3TXCI+ 22 Network 1 NA SP3TXCI- 23 Network 2 A* installed SP3RXC+ 24 NA LINESYNC SP3RXC- 25 Network 3 Powerup CPU Reset 26 Network 4 Power FPLED Down 27 DC Gnd #1 DC Gnd #1 DC Gnd #1

6 2070-6B Manual V Serial -12V Serial +5VDC STBY VDC +5VDC +5VDC 30 DC Gnd #1 DC Gnd #1 DC Gnd #1 31 NA NA NA 32 NA NA NA A1 Pin Assignments Pin A B C 1 SP3-TXD+ SP6TXD+ SP5TXD+ 2 SP3-TXD- SP6TXD- SP5TXD- 3 SP3-RXD+ SP6RXD+ SP5TXC+ 4 SP3-RXD- SP6RXD- SP5TXC- 5 SP3-RTS+ SP1- TXC(O)+ 6 SP3-RTS- SP1- TXC(O)- 7 SP3-CTS+ SP1- TXC(I)+ 8 SP3-CTS- SP1- TXC(1)- SP5RXD+ SP5RXD- SP5RXC+ SP5RXC- 9 SP3-DCD+ SP1-RXC+ SP3TXD+ 10 SP3-DCD- SP1-RXC- SP3TXD- 11 SP4-TXD+ SP4TXD+ SP3RXD+ 12 SP4-TXD- SP4TXD- SP3RXD- 13 SP4-RXD+ SP4RXD+ SP3RTS+ 14 SP4-RXD- SP4RXD- SP3RTS- 15 NA NA SP3CTS+ 16 NA NA SP3CTS- 17 NA NA SP3DCD+ 18 NA NA SP3DCD- 19 NA NA SP3TXCO+ 20 NA NA SP3TXCO- 21 DC Gnd #1 CH2 Disable SP3TXCI+ 22 Network 1 NA SP3TXCI- 23 Network 2 NA SP3RXC+ 24 NA LINESYNC SP3RXC- 25 Network 3 Powerup CPU Reset 26 Network 4 Power FPLED Down 27 DC Gnd #1 DC Gnd #1 DC Gnd # V Serial -12V Serial +5VDC STBY VDC +5VDC +5VDC 30 DC Gnd #1 DC Gnd #1 DC Gnd #1 31 NA NA NA 32 NA NA NA Installation The B has 5 front panel switches, 2 eight position dip switches for configuring the Modem, and a 5 position dipswitch for configuring the polarity of the backplane signals. There is 1 dip switch for each section of the Modem. SW3 is for Modem A which uses the C2S connector. SW7 is used for Modem B which uses C20S. The Front Panel toggle switches are labeled and organized so that they are close to the connector that they affect. The switches labeled ENABLE DISABLE turn the Modem section for SP1 to SP4 On or Off. When the switch is in the DISABLE position, the EIA- 232 section of C2 or C20 can be used without interference from the Modem. The FULL HALF switch allows you the select Full or Half Duplex operation for the Modem. With Half Duplex operation only the Audio Out pins in the M14 (C2, C20) are used. With Half Duplex operation, all communication is done over one pair of wires. This means that communication can go in only one direction at a time. Full Duplex Operation allows communication in both directions at once and therefore needs 2 pairs of wire (4 wire) to operate. The switch labeled ON OFF is used to turn power on and off to the B Module. This makes it safer to unplug and insert the B from the 2070 Controller with power on. The switch should be in the OFF position whenever the Module is going to be

7 2070-6B Manual 7 plugged in or taken out of the Controller. Make sure that the B is properly seated in its slot of the 2070 Controller and that the thumbscrews are snug before moving the switch to the ON position. The 5 V supplies in the C2 and C20 connectors are fused at 200 ma with a solid state fuse. This fuse will recover automatically when the excess load is removed. Do not attempt to take more than 100 ma from these connectors. The SW3 and SW7 dipswitches allow you to select the Anti-streaming option, whether you want local echo in the Half Duplex Mode, and if want to use the fast timing option. Both of the dipswitches perform the same function for its respective Modem. SW3 affects the channel A modem or SP1 or SP3. SW7 affects channel B or SP2 or SP4. SWITCH 3&7 POSITION TABLE POSITION FUNCTION 1 Full Duplex (not used) Off 2 Half Duplex (not used) Off 3 RTS/CTS time 4 Soft Carrier Time 5 Half Duplex local Echo 6 Rec. Squelch Time 7 Carrier Det. Time 8 Anti-Streaming Enable For normal 4 wire full duplex operation all of the switches should be OFF. If anti-streaming is wanted, turn switch 8 ON. If 2 wire half duplex operation is required, switch position 5 should be turned ON so the modem won t hear its own transmissions. Switch positions 1 and 2 are normally provided by the front panel toggle switches and should be left OFF so they don t conflict with the toggle switches. Turning switch positions 3, 4, 6, and 7 ON will cut the normal times for these functions in half. These times should be used as last resort in a system that is running out of time. Cutting the timing in half can result in the system having more errors than the system with standard timing. This is especially true in a half duplex, 2 wire system. The reason for this is the normal times give the system a chance to settle out between transmissions. The extra energy left in the system (on the wires) can cause errors in the receiver. The faster turn-around may be worth the occasional extra error in some systems. You can save 10 ms per transmission with the faster times. All of the timing switches should either be ON or OFF and not mixed. Switch position 8 is used to select the Anti-streaming option. The ON position enables Anti-streaming. With Anti-streaming enabled, the Modem will only be limited to transmitting up to about five seconds. If the Modem tries to transmit longer, the transmitting section will be turned off automatically. Dropping RTS will reset the Antistreaming circuit allowing the Modem to transmit again. Anti-streaming should not be enabled when it is known that a Master or Local Controller sends messages that are longer than 5 seconds. SW4 Digital Control Switch Switch SW4 controls the polarity of the signals coming off the backplane of the This switch is needed because of the different interpretations of the

8 2070-6B Manual 8 CALTRANS Specification concerning the backplane signals. This switch will allow the B to mate with any 2070 Controller. The SW4 switch has 5 positions with which you can control the polarity of all of the control and data signals. The following table defines the switch positions. POS Function Inverted TXD and RXD Modem Operatio n 1 RXD OFF ON 2 CTS ON ON 3 DCD ON ON 4 TXD ON OFF 5 RTS OFF OFF SW4 should normally be set to the Modem column and that is the way the modem is shipped. TYPICAL SYSTEM OPERATION In systems with FSK Modems certain control signals must be used correctly to assure reliable communication. 4-WIRE FULL DUPLEX systems use 2 pairs of wire to interconnect the Master and Slave Controllers. One pair carries data from the Master to the Local Controllers and the second pair carries data back from the Local Controllers to the Master. Audio Out from the Master connects to all of the Local Controllers AUDIO INs. All of the Local Controllers AUDIO OUTs are connect together and returned to the Master AUDIO IN. 2-WIRE HALF DUPLEX systems carry the transmitted data from the Master and Local Controllers on the same pair. All of the AUDIO OUTs of the system are connected together. With a 4-wire full duplex system you have to be concerned with the Local Controllers not transmitting at the same time since they all share the same wire. With the 2-wire Half Duplex system you also cannot have the Local Controllers talking over the top of the Master. There is also less time between transmissions to let the energy on the line dissipate. This extra energy on the line can interfere with the receiver circuits of the FSK Modem. These factors make the 2-wire half duplex system more error prone and slower than a 4-wire half duplex system of the same length and wire type. Proper use of the Handshake or control signals is essential to proper operation of an FSK Modem system. These signals are RTS, CTS, and DCD. RTS is an input to the Modem and Turns the transmitter ON. If RTS is active, the Modem is transmitting something. The Modem starts transmitting the MARK frequency (11,200 Hz) when the oscillator stabilizes and continues to transmit MARK until a SPACE is sent to the TXD Pin. 12 milliseconds after the RTS signal is active the Modem to generates a CTS signal (an Output) which tells the Master or local controller it can start to send data. 12 ms is required because the receiver Carrier Detect circuit requires 8 ms of Mark frequency before it will turn the receiver on. If you transmit data

9 2070-6B Manual 9 before the 8 ms, the receiver may chop off the first portion of the message or not ever turn the receiver on. If you have a system that is broadcasting continuously and you connect a Modem on to the line, you may find that the modem never receives any data. This is because the receiver circuit never sees 8 ms of continuous MARK frequency. When RTS drops, 10 ms of Soft Carrier will be automatically transmitted. The Soft Carrier Frequency is detected by the Carrier Detect circuit and shuts down the receiver. This helps prevent excess energy in the system from causing extra bits being generated in the receiver section. It must be remembered that the transmitter section of the Modem is still sending out Soft Carrier 10 ms after the last data bit is sent. This is especially important in a 2-wire half duplex system. HOW FAR WILL THE SIGNAL GO? This is an important question in higher speed FSK Modem operation. Typically, with a 0 db launch signal you can expect about 5-6 miles on 22 AWG wire. With 19 AWG wire, can go about 25% further. If more range is required, turning the transmitter output amplitude potentiometer clockwise can increase the transmitter output. These POTS are labeled AMP A for channel A and AMP B for channel B. An extra 10 dbm of output power is available. This will give you another 1.5 to 2 miles. You may have more crosstalk problems in some cable systems with the increase output. Additional distance can also be obtained by changing the modem input impedance on the middle units of a system. The input impedance of the Modem can be changed from 600 Ohms to 4.75K with a jumper located near the transformers for each channel. The jumper is labeled 600 and 4K75. Move the jumper to the 4K75 position to increase the input impedance. The Modems on the ends of the line should be left to 600 Ohms. This will significantly reduce the loading effects of each addition modem on a string. THEORY OF OPERATION The two Modem sections of the B are identical with the channel A modem on the normal component side of the PC Board and the B channel modem laid out on the backside of the PC Board. The two sections are identical except for reference designations. INTERFACE SECTION The interface section of B converts the EIA-485 signals that are on the back plane of the 2070 Controller to EIA-232 signals for the modem sections and C2 and C20 connectors on the front panel. The ENABLE-DISABLE switches on the front panel control the interface circuitry and steer the backplane signals to the Modem sections or the C2 and C20 connectors on the front panel. With the toggle switches in the ENABLE position, the modem sections are enabled and connected to the backplane. SP1 and SP3 are connected to the channel A Modem and the C2 connector. SP2 and SP4 are connected to the Channel B modem and the C20 connector. The SP4 serial port does not

10 2070-6B Manual 10 have the control signals available to drive the Channel B Modem so for dual modem operation the B should be plugged into the A2 slot. All of the signals going to the backplane or from the backplane are converted to TTL before being converted to RS-485 or RS232. U25 converts TTL to RS-485 for Channel A and U40 provides the same function for channel B for the RXD, CTS and DCD signals going to the backplane. U28 provides the RS485 to TTL conversion for the TXD and RTS signals for both channels. U13 and U32 convert TTL to RS-232 signals for the C2 and C20 connectors. These two ICs are driven from isolated supplies and signals. U19-23 are opto isolators that provide isolated signals for the A channel. U30-36 are the opto isolators for the B channel. U26, 27, and 33 provide the data selection and polarity selection for the A channel. U33, 38, and 39 are the equivalent for the B Channel. U18 and U24 are the Isolated +5V supplies for the A and B channels respectively. Relays KA1 and KB1. The ON/OFF switch will turn the power off to both sections. MODEM SECTIONS The Modem sections take an EIA-232 signal (TXD) and converts it to a frequency shift keying (FSK) analog signal that allows the data to be transmitted long distances over twisted pair or telephone lines. FSK is a modulation technique that generates one frequency for a Mark input and another frequency for a Space input. For EIA- 232, Mark is a negative voltage, and Space is a positive voltage. The Modems used in the Traffic industry closely follow the original Bell 202T specification for 1200 baud FSK Modems. The B/SM uses the frequencies specified by the Bell 202T specification while the B, being a 9600-baud modem, uses much higher frequencies as stated in the specification section. MODULATOR SECTION The Modulator section takes the EIA-232 Transmit Data and converts it to FSK. The Transmit Data is buffered by U28 and then drives the free running oscillator formed by U14 for CH A and U15 for CH B. The free running oscillator will oscillate at 3 different frequencies depending on the state of TXD (BA) and RTS (CA). Mark will cause a frequency of 11,200 Hz to be generated, Space will cause a frequency of 17,600 Hz to be generated, and when RTS drops, a Soft Carrier of 7800 will be generated for 10 milliseconds. After the 10 milliseconds, the output will be squelched until RTS is active again. U16 (CH A and U17 for CH B) does all of the timing including the Soft Carrier timing, RTS - CTS timing, and Receiver enable timing. One control, VR2 for CH A and VR5 for CH B, adjusts the space frequency of the oscillator. The Mark frequency is automatically set when the Space frequency is adjusted. VR3 (CH A) and VR6 ( CH B) adjusts the output level of the transmitter which is normally set for

11 2070-6B Manual 11 0dB (it can be adjusted up to +10 dbm). A 600 Ohm transformer is used to couple the signal to the phone lines or twisted pair. The transformer provides impedance matching and isolation from the phone lines. RECEIVER DEMODULATOR With Full Duplex operation, the incoming FSK signal is coupled to the receiver through 600 Ohm transformer T1. In Half Duplex operation the receive signal comes from the transmit transformer T2. This allows 2 wire operation. If the Local Echo switch is on, the receiver is turned off if RTS is active. The receive signal is first filtered and amplified by U1 CH A (U2 CH B) and then goes to the demodulator sections and carrier detect circuits. The demodulator section, U5 and U6, creates a positive voltage when a Space frequency is present and a negative voltage when a Mark frequency is present. VR1 (VR4 CH B) adjusts the slicing level so that the waveform from the demodulator is symmetrical. The signal is then filtered and amplified and converted to EIA-232 logic levels. The carrier detect circuit checks to see if the incoming signal is within the frequency band of the modem and is of sufficient amplitude for reliable communication. U7 (U8 CH B) does this job. If the signal doesn t meet specifications, the receiver is tuned off. MAINTENANCE AND ADJUSTMENTS The B will not normally need any preventative maintenance. The Output amplitude and frequency of the transmitter may need to be adjusted or checked if the error rate is becoming excessive. ADJUSTMENTS There are 3 potentiometers for each section of the B modem for making adjustments. The potentiometers are all located on the topside of the PC Board. The adjustments are as follows: 1) Frequency adjustment. The potentiometer adjusts the Mark and Space frequency. The potentiometer adjusts both the Mark and Space frequency with the POT adjusted so both frequencies are equal distant from their nominal values. 2) Output amplitude. Sets the output amplitude of the Modem. It is factory set to 0 db but can be adjusted to +10 dbm. 3) Symmetry. This adjustment varies the slicing level of the demodulator. If correctly adjusted, an alternating bit pattern will have a 50% duty cycle at the RXD output. AMPLITUDE ADJUSTMENT To set the Output amplitude you will need the following equipment: 1. A 600 Ohm load that will mate to the C2 and C20 connector. The 600 Ohm Load is connected to pins C and E of the connector.

12 2070-6B Manual A TRMS meter or oscilloscope capable of measuring a 20 khz signal accurately. 3. Screw driver for adjusting the Potentiometers. Mount the load on the C2 or C20 connector and connect the meter or oscilloscope across the load. Make sure the Modem is set for Full Duplex operation. Output an alternating bit pattern to the Modem from the 2070 and measure the amplitude with the meter. Adjust the amplitude with the Potentiometers marked AMP A and AMP B. The voltage read on the meter should be 0 db or V. The Oscilloscope s pattern should be about 2.2 V p-p. FREQUENCY ADJUSTMENT Use the same load as above and connect a frequency counter across the Load. You need to be able to generate Mark and Space signals to the B to check the frequency. Send a Space signal to the B section being checked. The frequency indicated should be Hz +/- 1%. Send a Mark signal to the Modem and verify that the frequency shown on the frequency counter is now /- 1%. If the frequency needs to be adjusted, The Potentiometer marked FREQ A or FREQ B should be adjusted with a continuous Mark or Space signal being sent to the B. SYMMETRY Connect an oscilloscope to RXD A or RXD B depending on whether the A or B section is being checked. Set the modem for Half Duplex operation local echo on (switch 5 off). Send an alternating bit pattern to the Modem. (RTS needs to be on for all of these tests). Make sure that you send 8 ms of MARK before the alternating bit pattern so that Carrier Detect will turn ON! Check that the CD LED is ON. The waveform should have a 50% duty cycle. The SYM A or SYM B potentiometer can be used to adjust the symmetry. TROUBLESHOOTING The B is a fairly complex Modem with hundreds of parts. This makes this Modem hard to trouble shoot for the average technician with limited experience with this modem. On the other hand this modem is constructed with top quality parts and so you should not experience many failures of this modem. There are numerous test points on the board that will allow easy access to most of the important signals in the Modem. The isolated signals on the C2 and C20 connectors should be measured referenced to pin N the isolated ground. This includes the signals on U13 and U32 The B is essentially two separate in one package. There are very few parts that are shared between the two modem sections. The Front panel ON/OFF switch and the connectors are included in this group. The chart below will help you find the problem if you decide to fix the B yourself.

13 2070-6B Manual 13 PROBLEM Both sections dead Modem is not generating Mark and Space Freq. Transmitter turns Off after 5 seconds No Receive Data RXD and CD LEDS on No Receive Data no LEDs No Receive Data CD LED on No Receive Data No LEDs EIA-232 signals not working in the C2 or C20 connectors No 5V on pin D of C2 or C20 connectors CAUSE Power coming into the board or the relays could have a problem. Check ON/OFF Switch or connectors and cables. Measure power at test points No RTS or TXD coming from Top Board. Check Enable/Disable switch. Check U28 and U33 interface chips. Oscillator not working. Check U14 and U15 of Modem. U16B and U18B can also turn off the Transmitter. Anti-streaming is turned on and transmissions of more that 7 seconds are being used. Buffer ICs U25 and U40 may have problem. Check RXD test points which are before the drivers U25 and U40. U26 and U27 are the control logic for CH A. U38 and U39 Control CH B. Check Enable/Disable Switch. Check output of input filter U3 pin1 (U4 pin 1), you should have a strong signal at this point. Check Demodulator section U5 (U6 CH B). The signal at U11 pin 1 (U12 pin 1) should be at least a couple of Volts. If output of the demodulator section looks good, check Carrier Detect circuit U7 pin 8 (U8 pin 8 CH B) which enables the receive section. Enable/Disable switch not in the Disable position. U13 and U32 are not working. Too much current being taken out of the isolated +5V. Keep current below 200ma. Isolated supplies U18 and U24 BAD.