COSA Xentaur Xentaur XDTL-HT - Manual (Page 23)

Modbus Communication
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Modbus Communication
The XTDL-HT™ can be monitored and controlled remotely via the standard Modbus communication
protocol. Every measurement and every menu field can be accessed via Modbus. Each field is assigned
to a unique Modbus register. See Appendix B for a complete list of Modbus registers supported by the
instrument. The instrument can be configured at the factory to support serial communication and/or
Ethernet communication.
The XTDL-HT™ supports the following Modbus commands:
Read Discrete Inputs
Read Coils
Write Single Coil
Write Multiple Coils
Read Input Register
Read Holding Registers
Write Single Register
Write Multiple Registers
Read/Write Multiple Registers
Mask Write Register
Report Slave ID
Read Device Identification
Refer to the COSA Xentaur Modbus Protocol User’s Guide for protocol details.
Modbus is a multi-node protocol. Each device on a Modbus network must have a unique address. Be
sure that no other device is using XTDL-HT™ address (default is 2). If there is a conflict, change the
address on the conflicting device or on the instrument.
Since Modbus is a master/slave protocol, it is important that the Modbus master waits for a response
before proceeding to the next command. The XTDL-HT™ can respond to most commands within
100msec but a 2 second wait time is recommended.