Modbus device disconnected but can be read from read test

[khalil]

Hello Dear,
I have a disconnected Modbus device, but when I try to read from Read Test its give a value.
the error log gives: read failed: operation time out.
please see attached image

[Daniel]

Try increasing timeout, should help

[khalil]

Try increasing timeout, should help

Hello @ Daniel
unfortunately it didn't help.
could it be a grounding/wiring issue!
while all the Modbus devices shown in the previous attached image are in the same loop!

[Daniel]

Correct wiring is always important as this can create noise. Increase the pool interval for all devices, start from 60sec.

[khalil]

Hello dears 
If I have a profile but some addresses are not connected, then does these non mapped registers polled?

[admin]

Entries without mapped objects are not polled.

[khalil]

Entries without mapped objects are not polled.

thank you admin 
another question
how the SL,LM poll mapped registers one by one or as a group.
if it pulled one by one, is it possible to make a group poll to decrease the traffic?

---

please advice regarding these errors,
 two Modbus RTU devices keep connecting and disconnecting

[admin]

Profile can be modified to use a single block read by setting read_count / read_offset parameters.
See these threads:
https://forum.logicmachine.net/showthrea...9#pid30319
https://forum.logicmachine.net/showthrea...8#pid19268

As for connection issues you might need to add read_delay to the profile.

[khalil]

Many thanks admin 
Will try and see
Edit:
I added the read_delay to one profile and the device connection issue solved.
Should I add the read_delay to all devices, or only to those showing connection error?
Also, If you could describe how the read_delay work, and how it solve the connection issue?

[Daniel]

LM is just waiting before sending new read request. Some slaves do struggle to answer quick requests. If you have same devices then I would add this to all of them.

[khalil]

LM is just waiting before sending new read request. Some slaves do struggle to answer quick requests. If you have same devices then I would add this to all of them.

Thank you Daniel