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Modbus Monitor Mode
 Moderated by: slychiu
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 Posted: Thursday Mar 30th, 2017 04:51 pm
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Joined: Saturday Apr 29th, 2006
Location: Singapore
Posts: 4480

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Modbus Monitor mode is a great help when you are setting up the Modbus Interface.
This shows the Modbus communications in both Transmit and receive directions.
It works for Modbus Master and Modbus Slave modes

Lines beginning with > show Transmit data ie transmit from UCM/Modbus to Modbus
Line beginning with < show Receive data ie receive from Modbus to UCM/Modbus

This is esepcailly useful in TCP mode as the IP addresses and port must be entered correctly for master and slave in order for communications to be successful

The information is raw modbus data. Refer to the Modbus standard documentation for the meaning of the data.

Modbus TCP and Modbus RTU have slightly different message structure. The example below is for TCP

To turn on Modbus Monitor, click on the Modbus Monitor Tab. To leave the Modbus Monitor, select another tab.

UCM/Modbus as Modbus Master will continually poll the Modbus Slave to which it is connected according to the Modbus to Comfort Table. Each modbus address will be polled in turn - when the slave address replies, the next Modbus address is polled, until the end of the table when it starts again from the top of the table

Note that in Modbus Monitor in Master Mode, the polling rate is slightly slower about 300 ms in order to avoid overflowing the monitor buffer

UCM/Modbus in Slave Mode replies only to a Poll from the Modbus Master which is connected to the UCM/Modbus.

Last edited on Monday Apr 10th, 2017 04:31 pm by slychiu

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