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Modbus RTU plugin setup

Andrei Ghiran

Posted on 12.01.2018 09:05

Hello!

I am trying to setup the Modbus RTU to read data from two slaves over RS485. I have two RS485 to USB converters. I have the following example messages:

STBD
Request: 20 04 00 00 00 07 B7 79
Response: 20 04 0E 06 AA 00 0A 00 E3 00 00 00 00 00 00 00 00 87 3C
PORT
Request: 30 04 00 00 00 07 B5 E9
Response: 30 04 0E 06 AA 00 0A 00 E3 00 00 00 00 00 00 00 00 8A F9

Interpretation:
20/30 SLAVE ID
04 FUNCTION CODE
0E NUMBER OF BYTES: 7*INT16 = 14
06AA ACTUAL PITCH -1000 - 0 - 1000 = -100 - 0 - 100%
000A ACTUAL SHAFT RPM 0 - 1000 RPM
00E3 LEVER DEMAND -1000 - 0 - 1000 = -100 - 0 - 100%
0000 PITCH DEMAND -1000 - 0 - 1000 = -100 - 0 - 100%
0000 SPEED DEMAND 0 - 1000 = 0 - 100%
0000 LOAD CTRL ACTIVE 0/1 = FALSE / TRUE
0000 PITCH LIMIT 0 - 1000 = 0 - 100%
8AF9 CRC

Attached is my setup which unfortunately I cannot check in my office. A colleague of mine will use it in the field.
Does the setup looks ok? Does anyone knows what Electrimin, Electricmax, Physmin, Physmax and Index stands for? Do I have to make the request like in the example or Dewesoft will do it automatically? Thank you in advance.


Attached files:
Michael Kalmbach

Posted on 09.08.2019 13:57

Andrei, did you ever get this sorted out? I have similar questions.

Andrei Ghiran

Posted on 09.08.2019 14:03

@Michael Kalmbach I never managed to fix it in time. For the next application we switched to Modbus TCP/IP and my colleague managed to properly configure it.


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