Sieger System 57 Modbus Interface Module Kit RS422/485 (05701-A-0312) Honeywell

Sieger System 57 Modbus Interface Module Kit RS422/485 (05701-A-0312) Honeywell

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 in 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:Easily fitted to the Engineering Card.Compatible with 5701, 5704 and 5704F Control Cards.Simple field connections, via the DC Input Card terminal block, forwire up to 2.5mm² (14 AWG).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 set Alarm Levels for all channels in the rack.Supports RS485, RS422 and RS232 electrical standards.Data signals isolated from System 57 power supply. Asynchronous serial link configurable for baud rate, parity and stop bits.

Primary and secondary channel operation. Half duplex operation. Multi-drop capability. Easily configured using Engineering Interface Software.

The reader should be familiar with the following terms that are used throughout this instruction manual:

MODBUS: 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: 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 'multidrop' bi-directional operation over distances up to 1.2km (3900ft).

RS422: 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).

RS232: 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 Rate: 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).

Bit Rate: The speed at which bits are transmitted, usually measured in bits per second (bits/s).

Parity: A technique used to detect single bit errors in a transmitted data byte (character) in electronic code transmission.

Stop Bit: A method to indicate the end of a transmitted data byte (character) in electronic code transmission.

Full Duplex: Refers to a communication system capable of simultaneous two way independent transmission of data.

Half Duplex: Refers to a communication system capable of transmission of data in either direction, but not simultaneously.

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 a node which controls transmission of data in 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.

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.