System 57 Modbus Interface Module Kit Operating
Contents
1. RS232 is an electrical standard that uses multi core cable carrying signals to transfer digital data RS232 permits interconnection of two communicating devices for bi directional operation over distances up to 15m 49ft Baud is a unit of signalling speed equal to the number of discrete signal events per second Not necessarily the same as bits per second The speed at which bits are transmitted usually measured in bits per second bits s A technique used to detect single bit errors in a transmitted data byte character in electronic code transmission A method to indicate the end of a transmitted data byte character in electronic code transmission Refers to a communication system capable of simultaneous two way independent transmission of data Refers to a communication system capable of transmission of data in either direction but not simultaneously 8 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 1 INTRODUCTION Simplex Refers to a communication system capable of transmission of data in a single direction only Multi drop A single communication line which is shared by a number of devices or nodes Node An intelligent device present within a data communication system which is able to communicate Host The host system is a master device that controls the system operation Typically a host will be either a PLC DCS or SCADA Graphics package Master A master device is a2. time and or date a real time clock hardware fault will occur To clear this the Engineering Card software should be reset ora valid time and date set Backplane Protocol Command Ignored No Yes Yes No Reserved for Zellweger Analytics use only Not applicable to Engineering Cards This command should not be used without a full knowledge of the System 57 Backplane Communications Protocol The contents of the holding registers are formatted into a backplane request frame as follows Registers 41n10 to 41n10 L 1 Request Data Registers 41n09 Request Identifier Registers 41n02 amp 41n03 Registers 41n007 Encoded Slot amp Sub channel Slave Request Length L Address 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 8 SPECIFICATION 8 1 ENVIRONMENTAL Operating Temperature 5 C to 55 Storage Temperature 25 C to 55 Humidity 0 to 90 RH Non condensing 8 2 EMC RFI CONFORMITY EN50081 Part 1 and Part 2 EMC RFI Generic Emission EN50082 Part 1 and Part 2 EMC RFI Generic Immunity 8 3 SERIAL COMMUNICATION Format Asynchronous Serial Data Data Bits 8 Speed 19200 9600 4800 2400 baud Stop Bits 1 or 2 Parity Odd Even or None Mode Half Duplex 8 4 MODBUS PROTOCOL Mode RTU MODBUS Functions 02 03 04 06 and 16 8 5 RS485 422 INTERFACE MODULE Power Supply Powered from Engineering Card Power Consumption 1 5W maximum Weight 30g Fi
3. 04 Oct 99 MODBUS Interface Module 05701M5006 5 COMMISSIONING AND MAINTENANCE INSTRUCTIONS 5 3 FAULT FINDING The following table identifies common problems and suggests appropriate actions Description of Fault Suggested Action General Failure Check the correct orientation and location of MODBUS module on the Engineering Card Check the Enhanced Software EPROM is fitted correctly on the Engineering Card and that link LK1 is set accordingly Check the MODBUS module configuration using the Engineering Interface Software No Communication Check the wiring between the DC Input Card terminal block TB2 and the host computer system port Check the serial communication configuration parameters of the host computer system and the rack are the same Ensure that the bus is correctly terminated See Section 3 4 3 If this is the case remove the bus terminators and retry communication For RS485 systems add network bias resistors as indicated in Section 3 4 4 Communication data Check the data signal wiring is not routed errors near sources of electrical noise Check for ground loops etc Ensure that the bus is correctly terminated See Ssction 3 4 3 If this is the case remove the bus terminators and retry communication For RS485 systems add network bias resistors as indicated in Section 3 4 4 If possible use an oscilloscope to examine the signals on the highway and take appropriate corrective action No respon
4. 11035 11034 11033 7 4 FUNCTION 04 READ INPUT REGISTERS 7 4 4 General There are two types of input register for each channel namely analogue signal value and animation value Analogue signal values are not supported for Fire Control Cards The input registers are returned as 16 bit data words The maximum number of registers that can be read in one frame is 64 The input register designations and functions are shown in the following sections 7 4 2 Analogue Register The measured sensor signal value of each sub channel is allocated to registers 30001 to 30065 These are formatted as 16 bit signed integers with a range of values from 10000 to 10000 in units of 1 10 fsd eg 02F3 equals 75 5 fsd and FFAB equals 8 5 fsd These values are undefined for Fire Control Cards 44 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 7 MODBUS FUNCTION REFERENCE The analogue registers for each sub channel are allocated as follows Sub Sub Sub Sub Channel 1 Channel 2 Channel 3 Channel 4 Analogue Analogue Analogue Analogue Register Register Register Register 1 2 3 4 5 6 7 8 7 4 3 Animation Registers A group of animation values are allocated for registers 30065 to 30128 These are intended to be used by graphics packages for defining the colours of various screen objects based upon the status of a sub channel A 16 bit unsigned word format is used which is defined so that the highest pr
5. Control Control Card Card Read card type Read serial number Read user field 1 tag name on control cards Read user field 2 Read range text Read range unit text Read range full scale Read range zero scale Read present signal in 96 fsd Read sensor signal scaled Read measured signal mV for bridge or mA for current loop Read bridge current error response given if polling a 4 20mA loop sensor Read card status Read channel status applicable to 5704 only Read EEPROM data reserved for Zellweger Analytics use only The sub channel number register should be loaded with the EEPROM page number for this request One page comprises of 16 bytes of data Read lowest signal in fsd Read highest signal in fsd Read fire counter Read date and time at last fire Read A1 threshold Read A2 threshold Read threshold C5 WY If the result register is loaded with a non zero value the contents of the result string registers should be ignored 51 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 7 MODBUS FUNCTION REFERENCE Response Format A The result of a successful card type request is loaded into the result string register at address 40n07 The following values are defined all others should be ignored 1 5701 Single Channel Control Card 2 5704 Four Channel Catalytic Control
6. MODBUS Interface Module RS485 422 10 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 1 INTRODUCTION ZELLWEGER ANALYTICS 05701 A 0287 ISS 9 oO 8 8 aoe 8 a D o 000000000000 Figure 2 MODBUS Interface Module RS232 11 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 1 INTRODUCTION Front Access 8 or 16 Way Rack Engineering Card Mk II DC Input Card 222008 UODZZZUH 0 MODBUS Interface Module ay Rear Access 8 or 16 Way Rack Figure 3 MODBUS Overview 12 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 2 CONTROLS AND FACILITIES 2 1 INTRODUCTION The 5701 and 5704 control systems provide a complete solution for the operational and engineering requirements of a multi channel fire and gas detection system Each control card within the rack system provides sensor drive signal acquisition gas concentration display and comprehensive alarm facilities for one or more fire or gas sensors The MODBUS Interface facility extends the capability of the control system by providing an external computer system with monitoring and control functions for every gas sensor or fire detector connected to the rack The operation and alarm integrity of the System 57 is not affected by the MODBUS Interface The digital data link uses a bi directional 8
7. above termination easy see Figure 1 In general RS485 transmitter circuits are specified as being capable of driving a minimum load resistance of 60 ohms therefore no more than two terminator resistors should be connected in parallel onto any one bus RS422 transmitter circuits are specified as being capable of driving a minimum load resistance of 100 ohms therefore no more than one terminator resistor should be connected onto any bus 3 4 4 RS485 Network Biasing Resistors Note In most systems network biasing resistors are not required It is recommended that these resistors are only added as part of a troubleshooting procedure In a multi drop RS485 system there are brief periods when no transmitter is enabled and the network is allowed to float During these periods noise or erroneous data may be detected at the receiver preventing communication or causing communications errors The 24 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 3 INSTALLATION INSTRUCTIONS System 57 MODBUS facility uses both hardware and software means to protected against this condition and therefore network biasing is not normally required Other devices on the network may be susceptible in this state and as a preventative measure two Network Biasing Resistors can be added externally to the transceiver at the host end of the bus so that the network is biased by a few volts when all transmitters are disabled The normal network t
8. computer systems It is essential that the same communication parameters are used on all nodes connected to any highway 4 2 HOST COMPUTER CONFIGURATION It is recommended that the host computer is configured to provide at least two retries in the event of a communication frame loss Refer to the documentation supplied with the host computer for details of its communication and MODBUS configuration 4 3 SYSTEM 57 CONFIGURATION 4 3 1 Introduction The System 57 MODBUS Interface facility is configured using the Engineering Interface Software EIS tool supplied as part of the Engineering Interface Kit Refer to the user manual supplied with the EIS for detailed instructions on using the software to change the configuration of a rack The following sections give a brief summary of the configuration options available for the MODBUS Interface Facility 4 3 2 MODBUS Interface Communication Parameters Several settings are available to configure a MODBUS node data communication link Typically communications use 9600 baud odd parity 8 data bits and 1 stop bit The number of data bits is fixed at 8 Other communication parameters are adjustable as follows a Mode Depending upon the electrical transmission standard being used select the required mode of operation for the communication link as follows i 5422 Data is transmitted on two separate twisted pair cables One pair carries data from the master to the slave device s the o
9. follows System 57 Interface Host Computer TB2 Abbr Name Direction Signal DB25 9 Pin Pin Pin Data Terminal Ready Receive Data Transmit Data Data Set Ready Signal Ground Some host computers will not transmit unless a valid input signal is present on its CTS Clear to Send input This is best achieved by linking the hosts RTS Request to Send and CTS connections The voltage between the signal grounds SGND of the two devices must not cause the common mode voltage rating of any device to be exceeded The signal ground of the System 57 interface is isolated from the System 57 ground to reduce earth loop current flow problems The cable screen should not be used as a data ground return and is best connected to the system ground at a single point only A comprehensive wiring example is shown Figure 14 31 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 3 INSTALLATION INSTRUCTIONS RS232 Host System 57 RS232 Mode SGND 5 4 o CTS TXD 3 RTS RXD 2 O DSR DTR DB9 SGND DSR CTS IBM PC 25 and 9 way D Type connectors Viewed into pins of RTS male connector DTE RXD TXD Figure 15 Common Personal Computer RS232 Connector Pinouts 32 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 4 CONFIGURING THE MODBUS FUNCTION 4 1 GENERAL The System 57 MODBUS Interface is highly configurable to allow compatibility with most host
10. identified as follows Mklhardware by the presence of only one 28 pin DIL IC socket on the card pcb b Mark II hardware by the presence of two 28 pin DIL IC sockets and a rectangular cutout near the centre of the card pcb See Figure 7 A summary of the MODBUS Interface installation procedure is shown below a Unpack and check the contents of the kit b Remove the Engineering Card from the rack c Install the Software Expansion EPROM Integrated Circuit d Install the RAM Expansion Integrated Circuit e Install the MODBUS Interface Module f Wire the DC Input Card terminal blocks to the host computer g Configure and Commission After installation is complete perform the commissioning procedures outlined in Section 5 The following sections provide a detailed explanation of the installation operations 3 2 UNPACKING On receipt carefully unpack the equipment observing any instructions printed on or contained in the packaging Check the contents for transit damage and ensure that the following items are present 18 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 3 INSTALLATION INSTRUCTIONS For the MODBUS Interface Module Kit RS485 422 a MODBUS Interface Module RS485 422 05701 A 0282 b Engineering Card Expansion Option EPROM integrated circuit 05701 A 0385 c RAM expansion integrated circuit type HN6264ALP d User Manual 05701 A 5006 For the MODBUS Interface Modul
11. limited by the cable capacitance and therefore the cable length should be kept as short as possible In dual highway configurations a separate twisted pair should be used for each highway however if required these may be contained within a single cable In order to ensure the correct operation and to meet European Standards for and EMC it is recommended that all field cables should be of the screened type with the cable screen connected at one end only If the screen is to be connected at the System 57 end use either the ground terminal of the DC Input Card the cabinet using a suitable metal cable gland or other suitable instrument earth point 3 4 3 RS485 422 Transmission Line Termination In RS485 or RS422 applications the two wire transmission lines must be properly terminated The simplest form of termination is typically with a 120 ohm resistor connected across the differential input as follows a In RS422 host systems a terminator resistance is only required at the receiver device located in the host and at the receiver device located in the System 57 node at the far end of the cable b n RS485 host systems a terminator resistance is required at the transceiver device located in the host and at the transceiver device located in the System 57 node at the far end of the cable For dual highway RS485 systems both highways should be terminated as described Jumper links are provided on the System 57 RS485 422 Module to make
12. node which controls transmission of data a communicating system by issuing requests to slave devices Slave A slave device will only transmit data onto the communication line in response to a request from a master device 1 3 CONSTRUCTION The System 57 MODBUS Interface is available pre installed in new systems or as a kit for retro fitting into existing systems Two kits are available one supporting the RS485 and RS422 electrical standards and the other the RS232 electrical standard Each kit consists of a A small pcb MODBUS interface module that plugs onto the Engineering Card J1 and J2 connectors b Two integrated circuits that plug into the expansion sockets provided on the Engineering Card Connections for the serial data interface are made via the six way expansion terminal block TB2 that is located on the DC Input Card An enhanced version of the Engineering Card software must be installed in order to provide the MODBUS Interface functions The new software which is fully compatible with the original Engineering Card software is provided as a plug in integrated circuit included in the kit 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 1 INTRODUCTION LK1 and LK2 fo ol Terminated Unterminated ZELLWEGER ANALYTICS 05701 A 0282 155 Termination Link Channel 2 Termination Link Channel 1 n n n n u u a m m ua pu g2on2uconocgcococ Figure 1
13. responses may be returned by the system 57 MODBUS interface 49 502 Issue 04 Oct 99 05701M5006 MODBUS Interface Module 7 MODBUS FUNCTION REFERENCE 01 02 03 06 ILLEGAL FUNCTION Only MODBUS functions 02 03 04 06 and 16 are supported This response is returned if any other requests are received ILLEGAL DATA ADDRESS The range of register addresses supported by each function are listed in the tables given above Any attempt to access a register outside of these ranges shall result in this error ILLEGAL DATA VALUE This exception is returned if the request has the incorrect length Also the maximum number of registers that can be requested by function 02 is 512 function 04 is 64 and functions 03 and 16 are 35 If these values are exceeded this exception response is returned SLAVE DEVICE BUSY Applies to functions 06 and 16 only Once a poll or command block s active register has been set it s contents must not be changed until the main program has carried out the request This exception is returned if any attempt is made to change an active poll or command block Note A function 06 or 16 that leaves the block unchanged will not generate this error 7 8 QUERY POLL DEFINITIONS The Engineering Card scans through the query poll blocks and carries out the following procedure when an active block is found a If the Slot number is between 1 and 16 the request is addressed to a contr
14. 5 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 2 CONTROLS AND FACILITIES 2 2 3 RS422 Operation A outline RS422 connection diagram is shown in Figure 5 RS422 Master TX Master Broadcast Highway System 57 Rx Slave Broadcast Highway Node 1 System 57 Tx Node2 Rx System 57 Node 3 Termination resistors fitted to host and last node only The System 57 RS485 422 module bus termination resistors are link selectable See Figure 1 and Section 3 4 3 System 57 Node 10 Figure 5 System Diagram for RS422 Connection When configured for RS422 mode transceiver Channel 1 is used for transmission from the System 57 RTU to the host computer and transceiver Channel 2 is used as a receiver for transmissions from the host computer to the System 57 RTU Depending upon the type of installation operation is possible over distances up to 1 2km 3900ft Although the EIA RS422 standard specifies only point to point applications the addressable operation of System 57 permits a modified broadcast mode topology that allows multi drop connection of up to 10 nodes Each System 57 node is held in a high impedance state until it receives an appropriately addressed request when it enables its transmitter for the duration of the response The terminal connections are TX A TX B Differential Transceiver Output from RTU RX A RX B Differential Receiver Input to RTU DGND Isolated Dat
15. 5006 7 MODBUS FUNCTION REFERENCE 7 1 INTRODUCTION This section does not give any detail of the MODBUS protocol For this information refer to the MODICON MODBUS PROTOCOL REFERENCE GUIDE PI MBUS 300 Rev G The System 57 MODBUS Interface supports the following functions Function 02 Read Input Status Function 03 Read Holding Registers Function 04 Read Input Registers Function 06 Preset Single Holding Register e Function 16 Preset Multiple Holding Registers It should be noted that MODBUS broadcast commands are not supported and will be ignored The MODBUS register values defined in this manual have the addressing convention used by Modicon DCS SCADA or PLOs ie These correspond exactly to the poll configuration of such SCADA package as th Intellution s Midicon I O driver for their FIX MMI SCADA package Other systems however may use different addressing conventions To configure these an understanding of the Modicon register address to the 16 bit address transmitted in a MODBUS request must be known The first digit refers to the data type stored in the register and therefore defines the MODBUS function request that should be used when polling it This digit is ignored when calculating the register address transmitted in the MODBUS request 1xxxx Registers address starting with 1 refer to the input status and are read using function 2 3XXXX Registers address starting with 3 refer to the analogue inpu
16. 6 Preset Single Multiple Holding Registers respectively 46 7 6 Function Read Holding Registers 49 7 7 Exception Responses 49 7 8 Query Poll Definitions 50 7 9 Command Poll Definitions 54 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 CONTENTS 8 SPECIFICATION 56 8 1 Environmental 56 8 2 EMC RFI Conformity 56 8 3 Serial Communication 56 8 4 MODBUS Protocol 56 8 5 RS485 422 Interface Module 56 8 6 RS232 Module 57 FIGURES Figure Page 1 MODBUS Interface Module RS485 422 10 2 MODBUS Interface Module RS232 11 3 MODBUS Overview 12 4 System Diagram for RS485 Connection 15 5 System Diagram for RS422 Connection 16 6 System Diagram for RS232 Connection 17 7 SYSTEM 57 Engineering Card Mark 11 21 8 Front Access Connections for DC Input Card and MODBUS RS485 422 Option Module 22 9 Rear Access Connections for DC Input Card MODBUS 5485 422 Option Module 23 10 Wiring Example Showing Multi drop Dual Highway RS485 Connections Termination Resistors Host Nodes etc 27 Wiring Example Showing Multi drop RS422 Connections Termination Resistors Host Nodes etc 28 12 Front Access Connections for DC Input Card and MODBUS RS232 Option Module 29 13 Rear Access Connections for DC Input Card and MODBUS RS232 Option Module 30 14 Wiring Example Showing RS232 Connections 32 15 Common Personal Computer RS232 Connector Pinouts 32 502 Issue 04 Oct 99 MODBU
17. 701M5006 7 MODBUS FUNCTION REFERENCE Card Card No Data STEL LTEL RATE Type 1 Type 0 Fire Walk Earth Remote Silence Output Test Fault Fault Fault ok ek POM POM FWHM BOND FON BOND BO BON AONI 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 6 6 6 6 7 7 7 7 8 8 8 8 9 9 9 9 WOM BOM BORD BOND BON AON There are five spare status registers for each sub channel eg 10012 to 10016 are spare on slot 1 sub channel 1 At present these always return 0 when read but are reserved for future use 43 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 7 MODBUS FUNCTION REFERENCE 7 3 16 Engineering Card Status Registers The Engineering Card processes the status information from all active cards and sub channels in the rack and provides registers to reflect the master alarm status for the whole rack as follows Global Status Registers Master Master Master Master Master Master Master Master Fault Inhibit A1 A2 A3 STEL LTEL RATE 11032 11031 11030 11029 11028 11027 11026 11025 Global Status Registers Master Master Master Fire Silence O P Fault The Engineering Card status is also accessible by reading the following registers Engineering card status registers Unlock Attention RTC Power EEPROM Timer ROM RAM LED On Required Fail Fail Fail Fail Fail Fail 11040 11039 11038 11037 11036
18. Card 3 5704 Four Channel 4 20mA Control Card 4 5704F Four Channel Fire Control Card 128 Engineering Card Mark II fitted with enhanced software Response Format B The data loaded into the response string will be an ASCII text null 00 terminated character string Two characters are packed into each response string register in byte reversed order The following example shows how the text 10 00 mV would be packed into the result string registers Hi Lo Hi LofHi Lo Hi Lo Oo 0 Response Format Status requests return a card or channel current alarm fault state as a set of bits in the result string register at address 40n07 The result format differs for Gas and Fire Cards as shown in the following tables Notes 1 The read card status request 12 when used with a 5704 Four Channel Control Card returns the master alarm state for all active channels on the specified card The read channel status request 15 should be used with 5704 Four Channel Control Card to determine individual sub channel alarm states 2 For Fire Cards the output fault and output active bits returned by the read channel status request 15 contain information about the switched outputs This information is only valid for sub channels 1 and 2 and refers to switched outputs A and B respectively For sub channels 3 and 4 the information contained in these bits should be disregarded 52 502 Issue 04 Oct 99 MO
19. DBUS Interface Module 05701M5006 7 MODBUS FUNCTION REFERENCE Gas Card Response Format Read Card Status Read Channel Status Master RATE Channel RATE Alarm Master STEL Channel STEL Alarm Master LTEL Channel LTEL Alarm Master A3 Channel A3 Alarm Master A2 Channel A2 Alarm Master A1 Channel A1 Alarm Master Inhibit Channel Inhibit Master Fault Channel Fault Always Clear Always Clear Fire Card Response Format Read Card Status Read Channel Status Master Walk Test Walk Test Status Master Silence Not Used Remote Input Fault Output Fault Earth Leakage Fault Output Active Hardware Fault Channel Walk Test Master Fire Channel Fire Master Inhibit Channel Inhibit Master Input Output Fault Channel Input Fault Always Clear Always Clear NOOR f C1 Co OOo omo Response Format 16 bytes of EEPROM data are returned by this request These are loaded into the lower byte of the result string registers from address 40n07 to 40n23 The upper bytes of these registers are cleared Response Format E For the Gas Card the alarm threshold data is returned by the request at address 40n07 The value is stored as a 16 bit signed integer in units of 1 10 fsd eg 02F3 equals 1 10 fsd and FFAB equals 8 5 fsd For the Fire Card the sub channel fire counter value is returned by the request at address 40n07 The value is stored as a 16 bit unsigned integer 53 502 Issue 04 Oct 99 MODBUS In
20. ERS RESPECTIVELY 7 5 1 General These functions enable the host to change the contents of the holding registers starting at address 40001 Depending on the contents of these registers commands to inhibit calibrate normalise or query sensors can be carried out Two types of holding register block are available one for polling a control card and the other for sending commands to a control card All registers use 16 bit data words The maximum number of registers that can be set by function 16 is 35 Note Broadcast function 06 and 16 requests are not supported and will be ignored 46 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 7 MODBUS FUNCTION REFERENCE 7 5 2 Query Poll Blocks A query poll enables the host to obtain operational parameters and data eg sensor current signal levels alarm levels etc There are 10 independent query blocks available to the host The Engineering Card scans through each in turn and for those with the block active flag set instructs the specified sub channel for the information requested Any response is stored in the appropriate result string location The poll block registers start at 40001 as shown in the following table where n ranges from 0 to 9 to indicate the poll block number Block Slot Sub channel Query Result Result Active Address Address Type String 40n01 40n02 40n03 40n04 40n05 40n07 to 40n35 The register functions are defined below a Block A
21. OV Out PSU 1 10 24V In PSU 2 or 24V Out PSU 1 11 0OVIn PSU 1 12 24V In PSU 1 PSU 1 and PSU 2 and AUX 1 and AUX 2 must be compatible with parallel connection Data Ground is electrically isolated from ground and must be connected to the remote apparatus Figure 8 Front Access Connections for DC Input Card and MODBUS 5485 422 Option Module 22 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 3 INSTALLATION INSTRUCTIONS TB1 12 24V In PSU 1 11 0VIn PSU 1 10 24V In PSU 2 or 24V Out PSU 1 9 OV In PSU 2 or OV Out PSU 1 8 424VIn AUX 1 7 O0VIn AUX 1 6 24V In AUX 2 or 24V Out AUX 1 5 OV In AUX 2 or OV Out AUX 1 4 24V Out Fused 3 OV Out Fused 2 Ground 1 Ground TB2 6 Ground 5 DGND 4 CH2 A RX A Connections for MODBUS Interface 3 CH2 B RX B Module RS485 422 2 CH1 A TX A 1 CH1 B TX B PSU 1 and PSU 2 and AUX 1 and AUX 2 must be compatible with parallel connection Data Ground is electrically isolated from ground and must be connected to the remote apparatus Figure 9 Rear Access Connections for DC Input Card and MODBUS 5485 422 Option Module 23 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 3 INSTALLATION INSTRUCTIONS To achieve fast reliable data connections good quality screened twisted pair cable should be used The maximum achievable data rate is
22. Operating Instructions Honeywell Sieger System 57 Modbus Interface Module Kit RS422 485 05701 A 0312 Modbus Interface Module Kit RS232 05701 A 0313 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 Helping to make a safer world Ensure that you read and understand these instructions BEFORE operating the equipment Please pay particular attention to the Safety Warnings WARNINGS The items of equipment covered by this manual are Not designed or certified for use in hazardous areas Designed for indoor use only Not to be exposed to rain or moisture CAUTIONS Use only approved parts and accessories with the System 57 Control System To maintain safety standards regular maintenance calibration and operation of the System 57 Control System by qualified personnel is essential IMPORTANT NOTICES Zellweger Analytics Limited can take no responsibility for installation and or use of its equipment if this is not done in accordance with the appropriate issue and or amendment of the manual The user of this manual should ensure that it is appropriate in all details to the exact equipment to be installed and or operated If in doubt the user should contact Zellweger Analytics Limited for advice Zellweger Analytics Limited reserve the right to change or revise the information supplied in this document without notice and without obligation to notify any person or organisation of such revision or cha
23. S Interface Module 05701M5006 1 INTRODUCTION 1 1 PRINCIPAL FEATURES The System 57 MODBUS Interface provides a facility for digital communication between the System 57 Control System and an external computer system MODBUS is a well supported digital data communication protocol which provides a set of standard commands by which system data can be communicated Two different interface modules are available to support the most widely used electrical interface standards thereby ensuring compatibility with most external systems Using the MODBUS Interface it is possible to read configuration alarm status and other information from any channel the rack and to perform calibration and other procedures The MODBUS Interface is commonly used to connect the System 57 Control System to plant control systems to provide central monitoring of system status often with graphical display The principal features of the MODBUS Interface are e Easily fitted to the Engineering Card e Compatible with 5701 5704 and 5704F Control Cards e Simple field connections via the DC Input Card terminal block for wire up to 2 5mm 14 AWG e Operates as a MODBUS RTU Supports functions 02 03 04 06 and 16 of the MODBUS protocol Provides sensor gas readings and alarm status for Fault Inhibit A1 A2 A3 FIRE STEL LTEL and Rate alarms from all channels in the rack Supports commands to Inhibit Reset Normalise zero Calibrate span and s
24. SR Data Set Ready SGND Signal Ground Transmit Data Ground Ground Ground OV Out Fused 24V Out Fused OV In AUX 2 or OV Out AUX 1 24V In AUX 2 or 24V Out AUX 1 OV In AUX 1 24V In AUX 1 OV In PSU 2 or OV Out PSU 1 24V In PSU 2 or 24V Out PSU 1 OV In PSU 1 24V In PSU 1 PSU 1 and PSU 2 and AUX 1 and AUX 2 must be compatible with parallel connection Data Ground is electrically isolated from ground and must be connected to the remote apparatus Figure 12 Front Access Connections for the DC Input Card and MODBUS RS232 Option Module 29 502 Issue 04 Oct 99 05701M5006 MODBUS Interface Module 3 INSTALLATION INSTRUCTIONS N O A A DN O gt a OD TB1 24V In PSU 1 OV In PSU 1 24V In PSU 2 or 24V Out PSU 1 OV In PSU 2 or OV Out PSU 1 24V In AUX 1 OV In AUX 1 24V In AUX 2 or 24V Out AUX 1 OV In AUX 2 or OV Out AUX 1 24V Out Fused OV Out Fused Ground Ground TB2 Ground SGND Signal Ground DSR TXD RXD Connections for MODBUS Interface Module RS232 Data Set Ready Transmit Data Receive Data DTR Data Terminal Ready PSU 1 and PSU 2 and AUX 1 and AUX 2 must be compatible with parallel connection Data Ground is electrically isolated from ground and must be connected to the remote apparatus Figure 13 Rear Access Connections for DC Input Card a
25. Test status of each sub channel 7 3 11 Earth Fault 5704F Only This bit reflects the earth leakage status of the control card An earth leakage fault will set the earth fault bits for all the sub channels on the control card 7 3 12 Remote Fault 5704F Only This bit reflects the fault status of the remote input on the control card A remote input fault will set all the remote fault bits for all the sub channels on the control card 7 3 13Silence 5704F Only This bit reflects the silence condition of the control card A card silence condition will set all the silence bits for all the sub channels on the control card 7 3 14 Output Fault 5704F Only This bit reflects the fault status of each switched output on the control card The fault status of output A will appear in the status bits of sub channel 1 The fault status of output B will appear in the status bits of sub channel 2 The Output Fault staus bits of sub channels 3 and 4 do not contain valid data and should be ignored 7 3 15 Register Allocation Table The status information relating to Gas Control Cards is different to that for Fire Control Cards however the same set of status registers is used In the following table where a register holds alternative information the Fire Control Card detail is shown in brackets The MODBUS Function 02 status registers for System 57 are allocated as follows 42 502 Issue 04 Oct 99 MODBUS Interface Module 05
26. The Engineering Card scans through each in turn and for those with the block active flag set instructs the specified sub channel to perform the function requested The command block registers start at address 41n01 as shown in the following table where n ranges from 0 to 9 to indicate the poll block number Block Slot Sub channel Command Command Result Backplane Active Address Address Type Data Protocol Command Data 41n01 41n02 41n03 41n04 41n05 41 06 41n07to 41135 The register functions are defined below a Block Active Indicates the Engineering card should use the parameters loaded in the block to poll the control card given by the Slot and Sub channel address fields A slot address of 32 generates a global command to all cards and sub channels in the rack As for query poll blocks an active command block cannot be changed until the Engineering Card has dealt with the request b Command Type The command poll function value see Section 7 9 for a list of System 57 command poll types Command Data Data applicable to the request eg for calibration commands this value represents the span gas concentration d Result When acommand is completed the block active register is cleared and this byte set to indicate success or failure as follows i A zero value indicates success ii A value of one indicates the command is not permitted via the MODBUS interface iii Other non zero values indic
27. a Ground 16 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 2 CONTROLS AND FACILITIES 2 3 MODBUS INTERFACE MODULE RS232 A outline RS232 connection diagram is shown in Figure 6 Tx Master Transmit Data System 57 Slave Rx Master Receive Data Figure 6 System Diagram for 5232 Connection The RS232 Interface Module has transmit and receive data lines and two handshaking lines The interface conforms to the RS232 standard giving 12V output drive Depending upon the type of installation operation is possible over distances up to 15m 49ft To protect the host computer against damage due to earth loops the interface signals are isolated from the System 57 power supply OV and Ground The terminal connections are designated as follows RXD Receive Data input to RTU TXD Transmit Data output from RTU DSR Data Set Ready input to RTU DTR Data Terminal Ready output from RTU SGND Isolated Signal Ground 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 3 INSTALLATION INSTRUCTIONS WARNING The Engineering Card and Upgrade Kit are susceptible to damage by static electricity and therefore the appropriate precautions should be taken 3 1 INTRODUCTION There are two versions of the Engineering Card The MODBUS Interface Kit can only be fitted to the Mk 2 Engineering Card With the Engineering Card removed from the rack the type of Engineering Card can be visually
28. ate failure and correspond to the error codes as defined in the System 57 Control Card User Manual for the type of card in the specified slot 48 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 7 MODBUS FUNCTION REFERENCE e Backplane Protocol Command Data If a BACKPLANE PROTOCOL request is loaded as a command type the data in these registers is used to format the command relayed to the control card CAUTION This request is reserved for Zellweger Analytics use only incorrect use may cause erroneous system operation 41n07 41n08 41n09 41n10 to 41n35 Where Length Indicates the number of data bytes The valid range is 0 to 21 Request Request identifier as defined in the Backplane Communications Protocol Data Request data as defined in the Backplane Communications Protocol The backplane communications protocol uses a byte format Therefore only the lower byte of the above registers shall be used when relaying the request to the backplane If the upper byte is non zero an invalid request error shall result 7 6 FUNCTION 03 READ HOLDING REGISTERS This function enables the host to read back the contents of the holding registers The maximum number of registers that can be read in one frame is 35 The holding register values are defined in Section 7 5 7 7 EXCEPTION RESPONSES The MODBUS exception response is detailed in the Modicon MODBUS manual Any one of the following exception
29. atus bits for each sub channel The maximum number of status bits read in one frame is 512 The status bit designations and functions are as follows 7 3 2 Card Type 1 Card Type 0 These two bits denote the type of control card as follows Card Type 1 Card Type 2 Control Card 0 0 5701 Single Channel Control Card 0 1 5704 Four Channel Control Card 1 1 5704F Four Channel Fire Control Card 40 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 7 MODBUS FUNCTION REFERENCE 7 3 3 No Data This bit can be used to determine the presence of an active card or sub channel During program initialisation this bit is set and all other status bits are cleared This bit is cleared only when data is received for the associated slot sub channel If no card is fitted in a slot this bit will always be set for all sub channels In a slot in which a 5701 card is fitted sub channels 2 3 and 4 will always have this bit set A 5704 gas card only transmits data for sub channels that are enabled therefore this bit is always set for the 5704 sub channels that are disabled A 5704F Fire Card always transmits data for all sub channels therefore this bit is cleared for all fire card sub channels even those that are disabled Once cleared this bit cannot be reset except by resetting the Engineering Card software 7 3 4 Fault This bit reflects the fault status of each sub channel There are three types of fault that affect this b
30. bit asynchronous serial connection that is configurable for baud rate parity and stop bits Two different modules are available one supports both RS485 and RS422 electrical interface standards and the other supports the RS232 electrical interface standard Depending upon the module type system configuration and the capability of the host computer various communication options are available as follows Interface Transmission Dual Highway Multi drop Mode Option Option Half Duplex Yes 31 Nodes Half Duplex Yes e Nodes Half Duplex The dual highway option provides a secondary or backup data link for increased communication integrity Multi drop configurations allow a single communication line to be shared by a number of devices reducing the number of communication ports required at the host computer RS232 provides the lowest cost solution for connecting a single System 57 rack to a host computer RS485 provides the best solution for multi drop connection of more than one System 57 rack to a host computer and also gives the option of a secondary highway RS422 is useful to provide multi drop connection where the host computer software does not have the facility for transceiver direction control transmit receive high impedance that is required with RS485 connections 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 2 CONTROLS AND FACILITIES In all cases the System 57 operates as a MODBUS Remote Termi
31. ctive Indicates the Engineering card should use the parameters loaded in the block to poll the control card given by the Slot and Sub channel address fields Once set the block cannot be changed until this flag is cleared by the Engineering Card when it has completed the request A SLAVE DEVICE BUSY exception may be returned see Section 7 7 if an attempt is made to change an active poll block b Query Type The query poll function value See Section 7 8 for a list of System 57 query poll types Result When a query is completed the block active register is cleared and this byte is set as follows to indicate success or failure as follows i A zero value indicates success ii A value of one indicates the command is not permitted via the MODBUS interface iii Other non zero values indicate failure and correspond to the error codes as defined in the System 57 Control Card User Manual for the type of card in the specified slot d Result string These locations hold any data returned in response to the query The data format of the result string depends upon the query type Refer to Section 7 8 for more details 47 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 7 MODBUS FUNCTION REFERENCE 7 5 3 Command Poll Blocks A command poll enables the host to control the operation of a channel eg inhibit reset calibrate etc There are 10 independent command blocks available to the host
32. dant highway The host system must be able to support this feature for redundant operation 34 502 Issue 04 Oct 99 05701M5006 MODBUS Interface Module 4 CONFIGURING THE MODBUS FUNCTION 4 3 3 MODBUS Interface Address The System 57 MODBUS facility operates as an RTU Remote Terminal Unit which provides for communication in the slave mode only A master device is required to control all communications within the system For RTU operation a unique addresses must be specified for each rack connected to the system to ensure unambiguous communication between the multiple nodes a Modbus Primary Address This specifies the required address between 1 and 247 for the main communication channel of the rack Each rack connected into the communication system must have a different address setting Modbus Secondary Address This feature only available when using the half duplex RS485 method of communication with the secondary bus enabled specifies the required address between 1 and 247 for the auxiliary communication channel Each rack connected into the communication system must have a different address setting however it is recommended that the secondary address is the same as the primary address Setting the address above 247 will disable the secondary highway 35 MANO0502 PM6 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 5 COMMISSIONING AND MAINTENANCE INSTRUCTIONS IMPORTANT For completely new Sy
33. e Kit RS232 a MODBUS Interface Module RS232 05701 A 0287 b Engineering Card Expansion Option EPROM integrated circuit 05701 A 0385 c RAM expansion integrated circuit type HN6264ALP d User Manual 05701 A 5006 3 3 INSTALLING THE MODBUS INTERFACE KIT Except for Step 6 which applies to the RS485 422 Module only the following installation procedure applies to both versions of the MODBUS Interface Kit 1 Isolate the SYSTEM 57 Rack from all power sources 2 Unscrew the two front panel screws that retain the Engineering Card and using the extraction tool supplied with the system pull the Engineering Card from the rack WARNING The Upgrade EPROM can be permanently damaged by incorrect insertion 3 Insert the Software Upgrade EPROM integrated circuit 05701 A 0385 into the socket IC2 on the Engineering Card ensuring that pin 1 of the IC is aligned correctly with pin 1 of the socket and that all pins are properly inserted into the socket Note If an IC is already fitted to socket IC2 this should be removed and discarded 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 3 INSTALLATION INSTRUCTIONS WARNING The RAM chip can be permanently damaged by incorrect insertion 4 Insert the RAM expansion integrated circuit HN6264ALP into the socket IC12 on the Engineering Card ensuring that pin 1 of the IC is aligned correctly with pin 1 of the socket and that all pins are p
34. ection A should be connected to all device receiver inputs A using one half of a twisted wire pair and the host transmitter output connection B should be connected to all device receiver inputs B using the other half of the twisted wire pair The host receiver input connection A should be connected to all device transmitter outputs A using one half of a twisted wire pair and the host receiver input connection B should be connected to all device transmitter outputs B using the other half of the twisted wire pair Ideally the A and B connections should be looped through each device If a spur is necessary the spur length should be kept at a minimum of typically less than 1m 3ft The data ground return connection DGND of all devices must also be connected together The voltage between the data grounds of the various devices must not cause the common mode voltage rating of any device on the bus to be exceeded The data ground of each System 57 interface is isolated from the System 57 ground to reduce earth loop current flow problems The cable screen should not be used as a data ground return and in systems spread over a wide area the cable screen is best connected to system ground at a single point only A comprehensive wiring example is shown in Figure 11 26 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 3 INSTALLATION INSTRUCTIONS R Primary TL Highway Secondary Highway CH1 B Termi
35. egative Going Input Threshold 0 6V minimum Input Hysteresis 500mv typical Common mode voltage 15V minimum to 15V maximum Protection Thermal shutdown Isolation 50V relative to system OV 58 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 59 Kebon P RODUC T Thank you for reading this data sheet For pricing or for further information please contact us at our UK Office using the details below UK Office Keison Products P O Box 2124 Chelmsford Essex CM1 3UP England Tel 44 0 1245 600560 Fax 44 0 1245 808399 Email sales keison co uk Please note Product designs and specifications are subject to change without notice The user is responsible for determining the suitability of this product
36. eld Terminals 2 5mm 14 AWG located on DC Input Card Cable Type Screened twisted pair with separate drain wire recommended 56 502 Issue 04 Oct 99 05701M5006 MODBUS Interface Module 8 SPECIFICATION Inputs Outputs Operating Modes Multi drop Capability Transceiver Specification Maximum Cable Length Maximum Data Rate Common Mode Voltage Input Sensitivity Input Hysteresis Output Drive Output Load Protection Isolation 8 6 RS232 MODULE Power Supply Power Consumption Weight Field Terminals Cable Type Inputs Outputs 5 Two RS485 transceivers Channel 1 Channel 2 Single RS485 Highway Dual RS485 Highway Primary and Secondary RS422 Highway 31 nodes maximum RS485 or 10 nodes maximum RS422 1200m 3900ft 19 2k baud 7V minimum to 12V maximum 200mV 20 typical 1 5V minimum fully loaded 54 ohms minimum Thermal shutdown 5OV relative to system OV Powered from Engineering Card 0 75W maximum 30g 2 5mm 14 AWG located on DC Input Card Screened multi core wire recom mended Two data RXD TXD and two handshake DTR DSR 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 8 SPECIFICATION Input Output Specification Maximum cable length 15m 49ft Maximum Data Rate 9600 bits per second Output Voltage 5V minimum Positive Going Input Threshold 3 0V maximum N
37. ermination resistors must still be kept in circuit The following diagram illustrates a typical biasing network 45V Bias Note 470 Resistor Where access to the host interface hardware is limited it RS485 BUS has been found that a single System 57 120 ohm bias resistor connected between the System 57 terminals TB2 pin 2 and TB2 pin 5 has been effective Host System Termination Resistor Bias Resistor DGND 3 4 5 RS485 422 Signalling Sense or Signal Polarity The EIA standard for RS422 and RS485 description of the polarity of the signalling lines states The signalling sense of the voltages appearing across the interconnection cable are defined as follows a The A terminal of the generator shall be negative with respect to the B terminal for a binary 1 MARK or OFF state b The A terminal of the generator shall be positive with respect to the B terminal for a binary 0 SPACE or ON state Not all manufacturers use the same convention for the polarity of differential data lines The System 57 RS485 422 Interface Module is labelled 1A 1B and 2A 2B for the primary and secondary transceivers in RS485 mode and A and B for the transmitter and A or B for the receiver in RS422 mode Other common signal notation is Alternative Notation A A Y High B B Z Low 25 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 3 INSTALLATION INSTRUCTIONS If the host de
38. et Alarm Levels for all channels in the rack Supports RS485 RS422 and RS232 electrical standards e Data signals isolated from System 57 power supply e Asynchronous serial link configurable for baud rate parity and stop bits Primary and secondary channel operation e Half duplex operation e Multi drop capability e Easily configured using Engineering Interface Software 502 Issue 04 Oct 99 05701M5006 MODBUS Interface Module 1 INTRODUCTION 1 2 COMMONLY USED TERMS The reader should be familiar with the following terms that are used throughout this instruction manual MODBUS RS485 RS422 RS232 Baud Rate Bit Rate Parity Stop Bit Full Duplex Half Duplex Modbus is a digital data communication protocol which provides a widely used set of standard commands by which system data can be communicated to an external device RS485 is an electrical standard that uses a twisted pair cable carrying differential signals to transfer digital data RS485 permits up to 32 transceiver nodes to be connected onto a single twisted pair highway for multi drop bi directional operation over distances up to 1 2km 3900ft RS422 is an electrical standard that uses a twisted pair cable carrying differential signals to transfer digital data RS422 permits a single driver and up to 10 receiver nodes to be connected onto the highway for operation over distances up to 1 2km 3900ft
39. ford Road Nuffield Estate POOLE Dorset BH17 ORZ United Kingdom Tel 44 0 1202 676161 Fax 44 0 1202 678011 email markcom zellweger analytics co uk email suggest the following corrections changes be made to Section Marked up copies attached as appropriate Yes No Please inform me of the outcome of this change Yes No For Marketing Communications Zellweger Analytics Limited Actioned By Response 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 CONTENTS Section Page GLOSSARY 3 1 INTRODUCTION 7 1 1 Principal Features 7 1 2 Commonly Used Terms 8 1 3 Construction 9 2 CONTROLS AND FACILITIES 13 2 1 Introduction 13 2 2 MODBUS Interface Module RS485 422 14 2 3 MODBUS Interface Module RS232 17 3 INSTALLATION INSTRUCTIONS 18 3 1 Introduction 18 3 2 Unpacking 18 3 3 Installing the MODBUS Interface Kit 19 3 4 Field Connections for RS485 422 Interface 21 3 5 Field Connections for RS232 Interface 29 4 CONFIGURING THE MODBUS FUNCTION 33 4 1 General 33 4 2 Host Computer Configuration 33 4 3 System 57 Configuration 33 5 COMMISSIONING AND MAINTENANCE INSTRUCTION 36 5 1 Start Up Procedure 36 5 2 Maintenance 36 5 3 Fault Finding 37 6 OPERATING INSTRUCTIONS 38 7 MODBUS FUNCTION REFERENCE 39 7 1 Introduction 39 7 2 Card Slot Number and Sub channel Designation 40 7 3 Function 02 Read Input Status 40 7 4 Function 04 Read Input Registers 44 7 5 Functions 6 and 1
40. iority event has the highest value The same set of animation registers is used for Gas Control Cards and Fire Control Cards however the values convey different information The data value for each register can be one of the following Condition Sub channel operating normally Sub channel Operating normally RATE alarm active Remote fault active LTEL alarm active Earth fault active STEL alarm active Fire alarm active A1 alarm active Fault active input fault or card fault A2 alarm active Output fault active A3 alarm active Card silence condition Fault active Walk test condition Inhibit active Inhibit active 45 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 7 MODBUS FUNCTION REFERENCE Normalising This status information is only available indirectly No data However it can be assumed that if a normalising available command is received from the host computer Calibrating the sub channel is then in the normalising state This also applies to the calibration command Note This status data is lost if the Engineering card software is reset 11 No data available for this sub channel The animation registers for each sub channel are allocated as follows Sub channel Sub channel Sub channel Sub channel 1 2 Animation Animation Animation Animation Register Register Register Register ONO 7 5 FUNCTIONS 06 AND 16 PRESET SINGLE MULTIPLE HOLDING REGIST
41. it a Acontrol card hardware fault This will set all the fault bits for the active sub channels on the faulty control card All other flags for the sub channel except the Inhibit flag and the Card Type bits will be cleared b Achannel sensor fault This will set the appropriate sub channel fault bit Provided the sub channel is not inhibited the sub channel Alarm flags will be cleared c Removal of a control card This will set all fault bits for active sub channels in the slot All other flags for the sub channel except the Inhibit and the Card Type bits will be cleared 7 3 5 Inhibit This bit reflects the inhibit status of each sub channel When set the Fault and Alarm sub channel flags are cleared Note If an inhibited control card is removed this bit remains set and therefore no fault will be indicated 7 3 6 A1 A2 A3 Gas Card Only These bits reflect the corresponding A1 A2 and A3 level alarm conditions of each sub channel 7 3 7 STEL LTEL Gas Card Only These bits reflect the corresponding STEL and LTEL time weighted alarm conditions of each sub channel 41 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 7 MODBUS FUNCTION REFERENCE 7 3 8 Rate 5701 Gas Card Only This bit reflects the Rate alarm condition of each sub channel 7 3 9 Fire 5704F Only This bit reflects the Fire alarm condition of each sub channel 7 3 10 Walk Test 5704F Only This bit reflects the Walk
42. level in For 5701 the sub channel register must 1 1096 fsd always be set to one Reset Channel Alarms Ignored Applies only to multi channel cards 54 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 7 MODBUS FUNCTION REFERENCE Command Description Command Applicable to to Global Type Data Command Gas Fire Possible Control Control Card Card Write EEPROM Page address Reserved for Zellweger Analytics use only Only applies to the Engineering Card 16 bytes of EEPROM data should be loaded into the lower byte of the command block registers at address 41n07 to 41n023 The upper bytes must be zero or an error response will result 24 Soft Re boot Card Ignored Yes Yes Yes No The sub channel register should be set to one 40 Accept Card Alarms Ignored No No Yes Yes The sub channel register should be set to one 41 Silence Card Alarms Ignored No No Yes Yes The sub channel register should be set to one Set A1 Threshold Alarm thres No Yes No No For 570 the sub channel hold as a Set A2 Threshold register must always be one signed word in 1 1096 fsd Set A3 Threshold Set Real Time Clock Ignored Yes No No No Five bytes of time data are required These parameters should be loaded into the command block register lower bytes with the high byte clear as follows 41n07 Year 41n08 Month 41n09 Date 41n10 Hour 41n11 Minute If an attempt is made to load the RTC with an invalid
43. nal Unit RTU acting as a slave device node and transmitting data onto the communication line only in response to a request from a master device The host computer system typically a PLC DCS or SCADA graphics package acts as the master device controlling the communication system operation The subset of MODBUS functions supported by the System 57 RTU are 02 03 04 06 and 16 The MODBUS broadcast commands are not supported and will be ignored however global commands are available to reset all cards in the rack simultaneously For a detailed description of the available commands and data formats refer to the System 57 MODBUS Function Reference given in Section 7 2 2 MODBUS INTERFACE MODULE RS485 422 2 2 4 General The RS485 422 Interface Module has two differential 5V transceivers designated channel 1 and channel 2 Each transceiver channel can be resistively terminated by setting LK1 and LK2 respectively see Figure 1 and Section 3 4 3 The interface signals are isolated from the System 57 power supply OV and Ground to protect the host computer against damage due to earth loops 2 2 2 RS485 Operation An outline RS485 connection diagram is shown in Figure 4 When configured for the RS485 mode transceiver Channel 1 is used in dual highway systems for the primary highway or the only highway in single highway systems Transceiver Channel 2 is used only in dual highway systems where it functions as the secondary highway Depending up
44. nation CH1 A resistors fitted on host and last CH2 B node only See EEE Section 3 4 3 RS485 Host System 57 RS485 Mode pean L gom System 57 RS485 Mode UP TO 31 Nodes Last Node Highways Terminated Figure 10 Wiring Example Showing Multi drop Dual Highway RS485 Connections Termination Resistors Host Nodes etc 27 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 3 INSTALLATION INSTRUCTIONS Termination resistors fitted on host and last node receiver only See Section 3 4 3 System 57 RS422 Mode System 57 RS422 Mode UP TO 16 Nodes Last Node Receiver Terminated Figure 11 Wiring Example Showing Multi drop RS422 Connections Termination Resistors Host Nodes etc 28 502 Issue 04 Oct 99 05701M5006 MODBUS Interface Module 3 INSTALLATION INSTRUCTIONS 3 5 FIELD CONNECTIONS FOR RS232 INTERFACE 3 5 1 General The field connections to the MODBUS Interface Module are made via the auxiliary terminal block TB2 on the DC Input Card The terminal block is a two part type to aid the connection of field cables without removing the DC Input Card The DC Input card terminal connections are shown in Figures 12 and 13 o a A N TB1 gt OON OQ 12 TB2 DTR RXD Data Terminal Ready Receive Data Connections for MODBUS Interface Module RS232 TXD D
45. nd MODBUS RS232 Option Module 3 5 2 RS232 Cabling The field terminals of the DC Input Card accept single or multi stranded wire up to 2 5mm 14AWG Cables should be routed carefully to avoid physical and environmental hazards such as mechanical stress and high temperatures To achieve fast reliable data connections good quality multi core screened cable should be used The maximum permitted cable length as defined by the RS232 standard is 15m 49ft 30 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 3 INSTALLATION INSTRUCTIONS In order to ensure the correct operation and to meet European Standards for and it is recommended that all field cables should be of the screened type with the cable screen connected at one end only At the System 57 end use either the ground terminal of the DC Input Card the cabinet using a suitable metal cable gland or other suitable instrument earth point 3 5 3 RS232 Connections The System 57 interface pinout connections follows the naming convention for data terminal equipment DTE and therefore usually requires a null modem type cable connection to the host computer Often the host computer will be an IBM Compatible personal computer system These are usually fitted with either a 25 way DB25 or 9 way DB9 male D type connector as illustrated in Figure 15 The System 57 signals corresponding host computer signal and DB type connector pins are as
46. nge If further details are required which do not appear in this manual contact Zellweger Analytics Limited or one of their agents 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 GLOSSARY Al Lower or Pre warning Alarm Level A2 Second Pre warning Alarm Level A3 Upper or Main Warning Level LED Light Emitting Diode LTEL Long Term Exposure Limit 8 hours TWA value HFI Radio Frequency Interference RH Relative Humidity STEL Short Term Exposure Limit 10 minutes TWA value Time Weighted Average j Refer to the appropriate National Standards Authority for details In the UK this detail is in the Guidance Note EH 40 89 from the Health and Safety Executive on Occupational Exposure Limits 1989 HELP US TO HELP YOU Every effort has been made to ensure the accuracy in the contents of our documents however Zellweger Analytics Limited can assume no responsibility for any errors or omissions in our documents or their consequences Zellweger Analytics Limited would greatly appreciate being informed of any errors or omissions that may be found in our documents To this end we include the following form for you to photocopy complete and return to us so that we may take the appropriate action 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 HELP US TO HELP YOU Marketing Communications From Zellweger Analytics Limited Hatch Pond House Address 4 Stins
47. ol card and the request type is validated in the same way as for the Engineering Card The slot number sub channel and request type registers are then used to format an internal communications request that is then sent to the applicable control card If successful the response data from the control card is formatted according to the request type and loaded into the result string registers The result register is then set to zero If an error response is obtained the failure value is loaded into the result register Finally the block active register is cleared If the Slot number is 17 the request is addressed to the Engineering Card and the request type is then validated Valid requests for the Engineering Card are listed below When completed the result string registers are loaded with the applicable data and the result 50 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 7 MODBUS FUNCTION REFERENCE register loaded with zero to indicate success Otherwise an invalid request value 67 is loaded into the result register Finally the block active register is cleared Ifthe slot number is greater than 17 an error value is loaded into the result register and the block active cleared The following table lists the query polls available whether they are applicable to the Engineering Card and or the Fire and Gas Control Cards and the format of the response Description Applicable to Response Gas Fire Format
48. on the type of installation operation is possible over distances up to 1 2km 3900ft In the multi drop mode up to 32 nodes including the host can be connected The terminal connections are CH1 A CH1 B Differential Transceiver Channel 1 Primary CH2 A CH2 B Differential Transceiver Channel 2 Secondary DGND Isolated Data Ground In a dual highway system the MODBUS uses at any one time only one of the two available highways either the primary or the secondary The interface automatically switches between highways when a communication failure is detected 14 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 2 CONTROLS AND FACILITIES RS485 Master Rx Tx Primary Highway Rx Tx Optional Secondary Highway lt Termination resistors fitted to host and last node only The System 57 RS485 module bus termination resistors are link selectable J See Figure 1 and Section 3 4 3 4 System 57 Node 32 Figure 4 System Diagram for RS485 Connection The highway switching process is controlled as follows a The inactive highway is continuously monitored for data communication b If data communication is detected on the inactive highway the inactive highway is assumed to be fully serviceable C If valid data communication ceases on the active highway and the inactive highway is perceived to be serviceable the MODBUS interface switches between channels 1
49. roperly inserted into the socket 5 Using small pliers or an electrical screwdriver gently remove the Engineering Card shorting link LK1 and replace to short pins 1 and 2 See Figure 7 6 This step applies to the RS485 422 module only For correct operation especially at high baud rates RS485 and RS422 highways should be resistively terminated In RS422 host systems a terminator resistance is only required at the receiver device located in the host and at the receiver device located in the System 57 node at the far end of the cable In RS485 host systems a terminator resistance is required at the transceiver device located in the host and at the transceiver device located in the System 57 node at the far end of the cable For dual highway RS485 systems both highways should be terminated as described above By default the RS485 422 module transceivers are unterminated If a resistive termination is required use small pliers or an electrical screwdriver to gently remove the shorting links LK2 Channel 1 or LK1 Channel 2 on the RS485 422 Module from pins 1 and 2 and replace to short pins 2 and 3 See Figure 1 and Section 3 4 3 7 Insert the MODBUS Interface Module into the socket headers J1 and J2 on the Engineering Card ensuring that pin 1 of the module pin headers is correctly aligned with pin 1 of the Engineering Card socket headers 8 Re insert the Engineering Card into the rack tighten the two front panel screw
50. s and go to the Section 3 4 20 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 3 INSTALLATION INSTRUCTIONS LK1 0g F 00000 7206 panaan Insert IC2 EPROM Insert IC12 RAM When inserting the MODBUS notch downwards notch downwards Interface Module ensure the correct alignment and orientation Figure 7 SYSTEM 57 Engineering Card Mark II 3 4 FIELD CONNECTIONS FOR RS485 422 INTERFACE 3 4 1 Connections The field connections to the MODBUS Interface Module are made via the auxiliary terminal block TB2 on the DC Input Card The terminal block is a two part type to aid the connection of field cables without removing the DC Input Card The DC Input card terminal connections are shown in Figures 8 and 9 3 4 2 RS485 422 Cabling The field terminals of the DC Input Card accept single or multi stranded wire up to 2 5mm 14 AWG Cables should be routed carefully to avoid physical and environmental hazards such as mechanical stress and high temperatures 21 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 3 INSTALLATION INSTRUCTIONS 1 CH1 B TX B 2 1 MODBUS Interface 4 CH2 A RX A Module RS485 422 5 DGND 6 Ground TB1 1 Ground 2 Ground 3 OV Out Fused 4 24V Out Fused 5 OV In AUX 2 or OV Out AUX 1 6 24V In AUX 2 or 24V Out AUX 1 7 AUX 1 8 24VIn AUX 1 9 OV In PSU 2 or
51. se from rack Check the address parameter used in requests issued by the host computer system matches the address allocated to the slave node In multi drop systems check that all nodes have a unique address 37 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 6 OPERATING INSTRUCTIONS The most common use for the MODBUS Interface Facility is to connect the gas detection system to a plant control system to provide central monitoring of the system status often with graphical displays Whilst the MODBUS protocol and communications system is well established and fully defined there are no standard MODBUS function formats defined for the communications of data from a gas system The host computer system will therefore require programming in order to interpret the signal and status data made available by the System 57 Control System Full details of the MODBUS function subset supported by the System 57 Control System are given in Section 7 Itis recommended that the host computer system should at a minimum be programmed to use Function 02 to collect alarm and status data from all channels of the System 57 Control System Function 06 or 16 must also be implemented if a facility to reset alarms is required Once properly configured and operating correctly the MODBUS Facility requires no further attention and therefore has no user controls 38 502 Issue 04 Oct 99 MODBUS Interface Module 05701M
52. stem 57 installations that have not previously been tested the commissioning procedure outlined in the Control System User Manual must be performed fully before attempting to commission the MODBUS Interface Facility 5 1 START UP PROCEDURE A detailed check of the system wiring should be carried out prior to this start up procedure Start up the system as follows 1 Ensure that the system power supply is off 2 Reconnect the power supply to the rack and verify that both Engineering Card front panel LED s flash for a short period after which the green POWER ON indicator illuminates continuously 3 After the power on inhibit time period ensure that the gas detection system is operating normally 4 Switch on the host computer system and initiate the MODBUS master operation 5 Using the alarm test mode of any one of the control cards in the rack simulate an alarm condition Refer to the Engineer s alarm relay test procedure in the Control System User Manual for more details 6 Check that the host computer observes the alarm and takes the appropriate action 7 Repeat steps 5 and 6 to simulate additional alarms encompassing all levels that are being monitored 8 Clear the simulated alarm s set up in Step 5 5 2 MAINTENANCE The MODBUS Interface Facility should be tested at regular intervals as outlined in the maintenance procedure given in the Control System User Manual 36 502 Issue
53. terface Module 05701M5006 7 MODBUS FUNCTION REFERENCE Response Format F Five bytes of time data are returned by this request these are loaded into the lower byte of the result string from address 49n07 to 40n11 as follows 40n07 Year 40n08 Month 40n09 Day 40n10 Hour 40n11 Minute The upper bytes of these registers are cleared 7 9 COMMAND POLL DEFINITIONS Command poll blocks are treated similarly to query poll blocks The following table lists the command polls available whether they are applicable to the Engineering Card and or the Fire and Gas control cards and if the command can be used globally Global commands are issued by setting the command poll block slot address register to 32 Description Command Global Data Command Eng Gas Fire Possible Card Control Control EI Card Card Inhibit Enable Card Zero Enables card The sub channel register should be set to one because this command is addressed to a card and not an Non zero individual channel Inhibits card Reset Card Alarms Ignored The sub channel register should be set to one Inhibit Enable Channel Zero Enables channel Applies only to multi channel cards Non zero Inhibits channel Normalise Command Ignored For 5701 the sub channel register must always be set to one Calibrate Command Reference gas level in For 5701 the sub channel register must always be set 1 1096 fsd to one New Sensor Calibration Reference gas
54. ther carries data from the slave device s to the master Up to 10 racks can be connected in multi drop mode onto the highway 33 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 4 CONFIGURING THE MODBUS FUNCTION i 5485 Data is transmitted on a single twisted pair cable either from the master to the slave device s or from a slave device to the master Up to 31 racks can be connected in multi drop mode onto the highway iii RS232 Data is transmitted on separate cables One carries data from the master to the slave device the other carries data from the slave device to the master Only one rack can be connected in this mode b Baud Rate Select the required speed for communication of the data This speed should be set to correspond to the baud rate of the host system Note The maximum recommended baud rate for RS232 is 9600 C Stop Bits Select the required number of stop bits in each data byte This should be set to correspond to the number of stop bits set for the host system d Parity Enable Enable or disable parity checking of the transmitted and received data This should be set to correspond to the parity checking set on the host system e Parity When parity checking is enabled odd or event parity checking can be used f Secondary Bus Fitted This feature only available when using the half duplex RS485 method of communication enables operation of a secondary or redun
55. ts and are read using function 4 4XXXX Registers address starting with 4 refer to the holding registers and are read using function 3 These registers can be written singly using function 6 or as a group using function 16 The xxxx refers to the 16 bit address transmitted in the poll plus 1 39 502 Issue 04 Oct 99 MODBUS Interface Module 05701M5006 7 MODBUS FUNCTION REFERENCE Examples Modicon Transmitted Function Description Address Address Slot 1 Subchannel 1 RATE alarm status input Slot 6 Subchannel 2 analogue value Poll block 1 subchannel register 7 2 CARD SLOT NUMBER AND SUB CHANNEL DESIGNATION Depending upon the rack width the System 57 racks can accommodate up to 8 or sixteen control cards For communication purposes each card slot has a unique slot address The slot addresses are numbered 1 2 3 8 or 1 2 3 16 from left to right across the rack The Engineering Card slot always has address 17 irrespective of the rack width To support both single and multi channel control cards the slot address is used together with a sub channel number For 5701 Single Channel Control Cards the sub channel number must always be set to 1 for 5704 5704F Four Channel Control Cards the sub channels are numbered from 1 to 4 to correspond with the cards four sensor inputs 7 3 FUNCTION 02 READ INPUT STATUS 7 3 1 General This function reads the channel status bits There are eleven st
56. vice is not labelled or the polarity is not evident some experimentation may be necessary The interface hardware can not be damaged by reversing the polarity 3 4 6 RS485 Connections The System 57 interface supports up to 32 nodes connected to a single RS485 highway A secondary or backup highway is also available if required All A connections within a highway should be connected together using one half of a twisted wire pair and all B connections within the same highway should be connected together using the other half of the twisted wire pair Ideally the A and B connections should be looped through each device If a spur is necessary the spur length should be kept to a minimum at typically less than 1m 3ft The data ground return connection DGND of all devices must also be connected together The voltage between the data grounds of the various devices must not cause the common mode voltage rating of any device on the bus to be exceeded The data ground of each System 57 interface is isolated from the System 57 ground to reduce earth loop current flow problems The cable screen should not be used as a data ground return and in Systems spread over a wide area the cable screen is best connected to system ground at a single point only A comprehensive wiring example is shown in Figure 10 3 4 7 RS422 Connections The System 57 RS422 Interface supports up to 10 nodes connected to a single RS422 highway The host transmitter output conn
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