Modbus communication error

[dineshkumargowd]

Dear Mikhail,

I am trying to communicate with Modbus Data acquisition module whose address is 1, baud rate is 9600, parity = No, stop bit = 1. I have assigned holding registers in modbus template. When i am starting the communicator i am receiving the communication error. Kindly help in this regard.

Initially i was using another version of Rapidscada, i was able to read those registers with the old version. But i am unable to read them from the new version of 5.7.

Following is the communication log for your reference

2019-08-01 18:29:28 Communication session with the Device 61 “E830_DAQ”, type: ScadaCommCommon, address: 1
Request element group
Send (8): 01 03 00 01 00 08 15 CC
Receive (0/5):
Communication error!
Request element group
Send (8): 01 03 00 01 00 08 15 CC
Receive (0/5):
Communication error!
Request element group
Send (8): 01 03 00 01 00 08 15 CC
Receive (0/5):
Communication error!

[Mikhail]

Hello,

Working with Modbus devices was not changed in Rapid SCADA 5.7. From the log we can see that the device doesn’t respond. You should check serial connection.

[dineshkumargowd]

Dear Mikhail,

It worked Now.

Device was not responded, since i have assigned the Holding registers(one register – 02 bytes) as Unsigned(16) initially. Later on changing them all to Signed(16), it worked well.

Serial connection was good, since it worked with other Modbus Master software.

Thanks for your immediate response.

[Mikhail]

Thank you for the info.

[Author]

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