Chelz96

QJ71MT91 MODBUS TCP, read holding register

6 posts in this topic

Hello everyone, 
I have a problem, i want to read inverter holding register using modbus tcp.
I am using QJ71MT91 and ABB580 FENA-21.
QJ71MT91 successfully opened and no error was detected.
I want to read the address to 101 and so on.
in automatic communication parameter >> I have tried changing the target MODBUS Device Head from 0 to 102, and I got error code 7360.
do I also have to use the auto refresh setting?
I ask for guidance

PLC Q03UDECPU : 192.168.3.181
PLC QJ71MT91 : 192.168.3.121
INVERTER : 192.168.3.11 
i use gx works2

 

best regard
chelz96

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BASIC_PARAMETER_2.PNG.0b90121e8fa8e7d794

DEVICE_ASSIGNMENT_100.thumb.PNG.51a147afAUTO_COMMUNICATION_PARAMETER_0.thumb.PNG

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The Modbus device assignment parameters you do not need to change this is for when you're a slave station.

You should change the  head adres to 101 if that is the adres you need, But since you get an exception error when you do possibly on the next 20 addresses don't exist. (101-121)

Try reading just one device first by changing the accees points to 1. 

When this works you will need to use the auto refresh to refresh(copy) bfm 1000h ------ (where youre information is stored) to the PLC Devices you want to use

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I see, so the problem is maybe the next address doesn't exist, I'll try your suggestion

for the memory address of the head buffer, do I need to change it from 1000h to 0000h?

Is there a possibility if the address we received doesn't match the address in question?

Thanks for your advice and sorry for the late reply @Gambit

Edited by Chelz96

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9 hours ago, Chelz96 said:

for the memory address of the head buffer, do I need to change it from 1000h to 0000h?

Is there a possibility if the address we received doesn't match the address in question?

 

No don't change that it should remain 1000. When you read 7 registers and you do another read than you change it to 1007 or higher.

You might have an offset of 1 in the address depending if they start at 0 or 1.

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Sir @Gambit, Thanks for your advice and I'm sorry for the late reply

it has worked according to the address.
head buffer memory remains 1000 because as you said, if i change it, it will offset the address if i want to start at 0

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It's just the first adress that stores the value of the modbus Dev you are reading.
So this is what you will autorefresh to Mitsubishi Devices like D0

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