Mapped modbus objects value issue

[gdimaria]

I have noticed the following problem in more than one system:

for example, we have a modbus HVAC device with temperature registers mapped to physical knx addresses in LM. 

In the same system there is a KNX touch panel which should display the temperatures in real time. This doesn't happen. 

The temperatures reach the LM, but not the touch. 

To display them from the touch I had to create an event script that reads the value and writes it to the bus, then you can see the temperatures on the touch panel. 

Obviously it doesn't seem like the best solution to me, especially in the case of dozens and dozens of register values to be retransmitted.

   


I also tried checking the "write on bus" option, but nothing happens.

[Daniel]

This option has nothing to do with writing to bus of registers, this refers only to device status object.
Go to register mappings and check it there. Log the object to see if values do arrive.
Why your pooling interval is empty?

[afbezerra]

Hello,

I Have the same problem.

I have the modbus equipment well registered and without errors. The modbus variables are mapped and updated. In the object log, only few variables have decoded values! Why?

This are a big problem to my project, because can´t atualize the values in SCADA.

I appreciate all the help.

[admin]

Most of your object log entries are group reads which don't have a value.

In one of the screenshots a device is marked in red meaning that there's a communication issue. Check Error log in the Modbus tab for more details. Usually communication errors are fixed when GND is connected between LM and all other Modbus devices.

[afbezerra]

I don't know if I explained the problem well. My LM is acting as an interface between several modbus devices and the Scada KNX. I created profiles for the various equipment and mapped the variables to KNX addresses. The values are read correctly by the LM.

In the sense of writing (KNX-> Modbus equipment), it works well. My difficulty is in updating the values of the objects (variables). In the log image I sent, it shows many read attempts, which have no response, despite the objects having value.

- In SCDA KNX I configured the periodic reading of these KNX addresses
- In LM, the different devices have a "Pool Interval" of 5s configured.
- In LM I also configured the variables with a "Pool Interval"

And yet, variables in SCADA KNX are only updated when the value changes.

What am I doing wrong?

Help please!

[admin]

And yet, variables in SCADA KNX are only updated when the value changes.

Can you explain why is this a problem? What is the point in sending the same value that has not changed? It just generates unnecessary bus load.

In the log image I sent, it shows many read attempts, which have no response, despite the objects having value.

LM won't respond to group read requests by default. It can be done via a script: https://forum.logicmachine.net/showthread.php?tid=5691

You don't need to enable poll interval for LM internal objects. This feature is used to poll other KNX device values.

Did you enable Write to bus for each mapped object in Modbus (not the device status object)?

[afbezerra]

I have made a scrit to read the objects, and now, it´s working Well!!!
Yes, I enable Write to each mapped object.
Thanks