8 023 IGYR Building Level Network, PROFIBUS The Building Level Network (BLN) serves to exchange building management data between process units and the PC operator station "IGYR Insight". In IGYR, PROFIBUS is used to accomplish this type of data communication. PROFIBUS (PROcess Field BUS) is a standardised field bus conforming to DIN 19 245 which facilitates "open communication in the field". In general, the data interface is standardised for all PROFIBUS-capable units. In order to transmit object data such as process values, operating statuses, messages, etc., company-owned data profiles are used. Use In IGYR, the Building Level Network (BLN) on the basis of PROFIBUS is used to communicate data between the following units: among PRU units (see data sheets 8001, 8241, and 8411) between the process unit and the PC operator station "IGYR Insight" between IGYR and third party units BLN structure with PROFIBUS The illustration below shows the principal structure of a BLN with PROFIBUS. The network wiring (bus) comprises a 4-core, shielded cable. P1 N1 N2 N3 8023B01 E1 E2 X1 V1 E4 N4 V2 E3 N5 E5 N1.. N5 E1.. E5 V1 V2 P1 X1 Process units PRU PROFIBUS terminator P1.1U PROFIBUS repeater PLR1.1, as a T-branch decoupler PROFIBUS repeater PLR1.1, as a repeater for long bus lines PC operator station "IGYR Insight" PROFIBUS junction box PLU1.X01 with terminator This data sheet provides a description of the Building Level Network or PROFIBUS as used in IGYR. Please remember that small deviations compared to different PROFIBUS applications (no general differences, however) may occur. We will not discuss data communication between IGYR units and third party devices. Siemens Building Technologies CM2N8023E / 01.1999 Landis & Staefa Division 1/8
Application ISO/OSI layer model Wherever automation systems are used, an open, supplier-independent bus interface is desired. As a result, the field bus standard "PROFIBUS" was developed. The basis for PROFIBUS was the ISO/OSI layer model (International Standardization Organisation/Open Systems Interconnection). The tasks required for communication were divided in seven levels. PROFIBUS structure The PROFIBUS has been design following the ISO/OSI 7 layer model. Layer 7 Layer 6 Layer 5 Layer 4 Layer 3 Layer 2 Layer 1 Application Layer Presentation Layer Session Layer Transport Layer Network Layer Link Layer (securing) Physic.Layer(bit transm.) Layer 0 Medium 8023Z02E Layers 1 and 2 define the following: the line medium, the physical and electrical characteristics of the interface, the bus access procedure, the transmission protocols, and the telegrams. Layer 7 defines: the application protocol as well as the interface to the user process. Data transmission Token Passing Principle The functions of layers 3 to 6 are reduced in PROFIBUS applications and have thus been integrated in layers 2 and 7. The sections below provide a detailed description of data transmission. In IGYR, the terms Station or Master station are synonymous to Process unit. PROFIBUS uses the so-called Token Passing Principle. With this type of transmission, the token (similar to a baton at a relay race) is passed from station to station. As soon as the authorised station sends its own package(s) or when the time available for sending has expired, the token is passed to the station with the next higher address. When a station receives the token, it becomes the master station, i.e. only that station has access to the bus. If this station also has sending orders, it can send them off. If it does not have any sending orders, the token is passed on to the next station. Within the bus access, only data between the master and the receiving station are exchanged. However, communication is bi-directional, i.e. data is sent and received. Target token rotation time Real token rotation time In order to ensure that each station is able to send following expiration of a certain period, a target rotation time for the token is determined. The real rotation time for the token depends on the bus load and the number of stations on the logical ring. A typical value for a real token rotation time would be 10% of the determined target rotation time. CM2N8023E / 01.1999 Siemens Building Technologies 2/8 Landis & Staefa Division
Logic token ring With the token passing principle on peer stations, the token passes a so-called 'logic token ring'. 1 3 7 15 12 8023F01 Idle time An idle time is inserted between two mutually independent telegram chains (new data transmission). This fulfils two functions: as soon as data transmission between the master and the receiver station is completed, the master stations switches off transmit mode and starts idle time. when idle time has expired, all stations return to receive mode (excepting the currently active master station). The master station sends the target address of the next telegram to the receiver stations (token passing). All receiver stations then check the address. Following the check, a new data transmission is started with the addressed station. All non-addressed stations immediately disconnect from the bus and return to process handling. Selective 'monitoring' reduces bus administration time (protocol overhead time). Characteristics The following PROFIBUS characteristics apply to IGYR: bus access via token passing with asynchronous, bit-serial transmission, i.e. the receiver synchronises itself upon start bit recognition (bit synchronisation) synchronisation without slippage, i.e., after the stop bit of the n-th UART character, the start bit of the (n+1)-th UART character immediately follows bits are transmitted in NRZ code (NRZ = Non Return to Zero; general type of data transmission in digital technology) half-duplex mode (data are transmitted in one direction only per transmission, i.e., sending or receiving) time and date synchronisation with broadcast, i.e. the station with the lowest address becomes the master station and sends the time and date values to all other stations. Telegram structure UART characters In general, one information consists of several, consecutive UART characters. This string of UART characters creates a telegram. A UART character (Universal Asynchronous Receiver/ Transmitter) comprises a start bit, eight data bits as well as one parity and one stop bit. The bits can be directly sent and received from a standard UART component. St LSB MSB Pb Sp St D0 D1 D2 D3 D4 D5 D6 D7 8023D01 St Start bit, always logic "0" D0..D7 Data bits Pb Parity bit Sp Stop bit, always logic "1" Siemens Building Technologies CM2N8023E / 01.1999 Landis & Staefa Division 3/8
Telegram format Data field A telegram begins with a start bit or start byte. The start byte SD (Start Delimiter) contains the code of the telegram format followed by the destination address byte DA (Destination Address) and the source address byte SA (Source Address) which identify transmitter and receiver. The control byte FC (Frame Control), used by all receivers to identify the type of telegram (poll, acknowledgement, reply), then follows. The data bytes follow the FC control bytes. A data field may comprise one or several data bytes. SD DA SA FC Data field FCS ED 8023D02E Telegram format, data field length for IGYR: up to 220 data bytes Telegram termination with telegram check A check byte for data backup FCS (Frame Check Sequence) and an end byte ED (End Delimiter) terminate the telegram. If a transmission is error-free, an acknowledge (positive checkback signal) follows. If a transmission is faulty (not-acknowledge), the entire telegram is cancelled and the transmission repeated. Design Digital signals On the first pair of wires, consisting of lines and, the digital signals are transmitted. The signal levels comply with standard RS-485. The bit values for logic "0" and "1" are defined by the sign before the voltage level. This technique ensures that, on the receiver side, even noisy signals can be identified. S W 8023V08 S W Shielding PROFIBUS cable Remote supply voltage The second pair of wires, consisting of the and lines, is used for remote supply voltage. The line carries the positive potential whereas the line serves as the ground wire or as potential equalisation between the individual bus units. When no PROFIBUS repeaters are used, the voltage signal is approximately + DC 4.3 V. When repeaters are used, is approximately + DC 28 V. At a remote supply voltage of + DC 28 V, all repeaters are interlinked on the DC voltage side, that is, they are switched in parallel. Bus terminator Both ends of each bus line must be equipped with a bus terminator. This also applies to T-branches with repeaters. Bus terminators (also named PROFIBUS terminator or P1.1U terminator in IGYR) are required to avoid signal reflections predefine voltage potentials on the bus lines and The P1.1U bus terminator contains a voltage control which limits the voltage signal to + DC 5 V. The voltage potentials for and are derived from that voltage signal. CM2N8023E / 01.1999 Siemens Building Technologies 4/8 Landis & Staefa Division
Engineering notes Bus structure For data communication with PROFIBUS, you do not need to set any parameters on the IGYR side or load any software data. On the PRU process unit and the "IGYR Insight" PC, only the communication cards must be equipped with address plugs (data sheets 8271 and 8481). For addressing information, refer to document Z8020: IGYR System Communication. In a T-branch you must always use a PROFIBUS repeater PLR1.1 for decoupling (for repeater information, refer to data sheet 8923). Without using a PROFIBUS repeater, the maximum bus length of a section is 1200 m (with three repeaters max. 4800 m). No more than three PROFIBUS repeaters may be switched in series between two stations, i.e. a data link between two stations may not pass more than three repeaters. When coupling T-branches to a PROFIBUS repeater, the following applies: A T-branch connection can be made at terminals U_1 or U_2. Two T-branch connections on terminals U_1 and U_2 are permissible. Shielding Lightning protection The bus cable shielding should be earthed at both ends. For more detailed information, refer to "Lightning protection" below and "Wiring Diagrams". Landis & Staefa does not require lightning protection for the Building Level Network on the basis of PROFIBUS. Observe local regulations regarding lightning protection and potential equalisation. : Remember that absolute lightning protection can never be guaranteed To provide lightning protection, we recommend the following measures: when the shielding is earthed at both ends, a potential equalisation line from building to building is required. Whenever cables enter or leave a building, external protective equipment such as a lightning arrestors must be installed. when no potential equalisation line from building to building is available, the shielding must be earthed at one end only. The unearthed side of the shielding must be connected to a so-called non-linear-resistance arrestor. Installation notes The bus cable is connected directly to the terminals of the units and looped (with the PRU process units, to terminal block III PUX1.1U). At both bus ends, the PROFIBUS terminator must be fitted observing correct polarity (terminator P1.1U must be connected to the respective terminals of the bus units) The bus cable may be laid together with the lines of the AC 24 V operating voltage and the lines of the 3 x AC 400 V three-phase network For wiring and earthing guidelines in IGYR, refer to the Mounting and Installation Handbook. Commissioning notes Bus wiring Repeater Check the following aspects for bus wiring, PROFIBUS repeater, and process units prior to commissioning. When wiring the bus, ensure that the terminators are attached at each bus end and that the shielding is earthed locally. The baud rate for the PROFIBUS repeaters must be set to 93.75 kbaud. Siemens Building Technologies CM2N8023E / 01.1999 Landis & Staefa Division 5/8
Process units Downloading the configuration data Ensure that the communication cards are inserted and addressed at the process units (addressing for PRU1 with address plug; for PRU2 in terms of software). In the PRU1 or PRU2 as well as in the PC operator station "IGYR Insight", the communication cards must be inserted prior to downloading the configuration data. Downloading to PRU1 must occur via PROFIBUS. (Following the download via the serial interface, the PRU1 is ready, but without communication via PROFIBUS). Downloading to PRU2 can be performed via PROFIBUS or serial interface. But, remember that in the PRU2, user texts for the local printer can only be loaded via PROFIBUS. Technical data The following technical data apply to PROFIBUS when installed and operated as in IGYR: Physical and link layer as per DIN 19 245, part 1 Bus protocol as per ISO/OSI Layer 1 and 2 Application layer DIN 19 245, part 2 Application protocol as per ISO/OSI Layer 7 Interface definition as per EIA RS 485 Transmission mode Half-duplex Target rotation time Real rotation time Telegram format with hamming distance Telegram repetitions in case of error 1 s 0.1 s (typically) 4 Hd twice (default) Rate of transmission 93.75 kbaud Tolerance of baud rates ± 0.3 % Line length without signal amplification Line length with signal amplification max. 1200 m max. 4800 m Number of PROFIBUS repeaters in series max. 3 Permissible signal attenuation 6 db Bus cable Wire diameter Cable impedance at 100 khz 4-core, shielded min. 0.6 mm 120 Ohm Galvanic separation of bus (from power supply) Communication card PAK1.1 in PRU1 PC communication card PLU1.AT.. PROFIBUS repeater PLR1.1 no yes yes IGYR units Refer to the following data sheets for information on IGYR units that can be connected to the PROFIBUS: Process units PRU1... 8241 Process units PRU2... 8411 Communication set for PRU1 PAK1.1.. 8271 *) Communication cards for PRU2 PEC1... 8481 *) PC Communication card PLU1.AT.. 8555 *) PROFIBUS repeater (U-bus repeater) PLR1.1 8923 PROFIBUS terminator P1.1 8961 PROFIBUS cable range 8961 PC operator station "IGYR Insight" 8512 *) Connection for PROFIBUS and modem CM2N8023E / 01.1999 Siemens Building Technologies 6/8 Landis & Staefa Division
Connection diagrams Example 1 PROFIBUS structure comprising a bus segment with repeater and a bus segment with T-branch. The T-branch must be implemented with a repeater. N1 N2 E1 E2 E3 V1 1 1 1 1 2 2 2 2 1 N3 N4 E4 E5 V2 1 1 1 1 2 2 2 2 2 N5 N6 E6 8023V06 N1.. N6 E1.. E6 V1 V2 Process units PRU PROFIBUS terminator P1.1U PROFIBUS terminator PLR1.1, as repeater for long bus lines PROFIBUS repeater PLR1.1, as decoupler for T-branch Siemens Building Technologies CM2N8023E / 01.1999 Landis & Staefa Division 7/8
Example 2 You can connect a PC to the process unit's tool interface (e.g. for service purposes). This connection allows for comprehensive access to PROFIBUS. N1 N2 E1 W1 8023V09 N1, N2 Process units PRU E1 PROFIBUS terminator P1.1U W1 PROFIBUS- / RS232 tool cable PUW1.1 Example 3 PROFIBUS structure comprising a bus segment with coupling to "IGYR Insight" via a junction box. W2 N1 X1 N2 E1 6 5 3 8 8023V07 SH SH N1, N2 Process units PRU E1 PROFIBUS terminator P1.1U W1 PROFIBUS- / RS232 tool cable PUW1.1 W2 PROFIBUS connecting cable PLU1.W5 X1 PROFIBUS connecting cable PLU1.X01 Pin assignment PLU1.W5 The following applies to pin assignment on a 9-pin subminiature D-plug: 3 5 6 8 (Rx/TxD-P) (DGNP) (VP) (Rx/TxD-N) 3 5 6 8 8023Z01 Pin Ref. Signal Meaning 3 Rx/TxD-P Receive/send data, positive 5 DGND Data ground 6 VP Supply voltage, plus remote supply voltage 8 Rx/TxD-N Receive/send data, negative 1999 Siemens Building Technologies Ltd. CM2N8023E / 01.1999 Siemens Building Technologies 8/8 Landis & Staefa Division