Systemair RS-485

[Evens]

Hi,
 
I see that many already have integrated their Systemair ventilation system thru RS-485, I’m trying to do the same, but I’m having difficulties connecting. I’m using the RJ45 plug at the top of the ventilation unit connected to the first RS-485 port at the LM. I’m running RTU scan and can’t find anything. In the Modbus manual supplied by Systemair, the drawing shows that A = pin 5 and B = pin 4. I have tried this and switching A and B. Does anyone have an idea what I’m doing wrong?

Manual:
https://www.systemair.com/globalassets/d.../40903.pdf
 
BR Even Sundgot.

[admin]

Try using RTU read test. Scan might not work for some devices. Check that baud rate and parity settings are correct. When reading make sure you have valid register address. Some devices silently ignore reads to registers that are not present instead of replying with an error.

[Evens]

I have set ID to 1. Baud rate to 19200 and parity to Even an the panel of the Systemair. I have connected A to A on LM and B to B on LM.

I have tried to read several address from the manual but only got timeout.

I noticed something in the manual, it looks like the Ventilation system is Modbus Master, am i correct?
On page 4. Chapter 6. Position 4. Modbus Master. How can i read from a master?

[chriscroko]

The ventilation system is a modbus slave. In the manual the Master is an indication of were the line termination should be. And the master will be your LM.
Your unit is indicated by the RJ45 plugs, Position 2 on page 4.

The setup you have set, has this been setup the same way on the LM? I am reading a Flexit unit from my LM, and have set up Half-Duplex on it and the same parameters as set on the unit.

[Evens]

Hi,

Ok, thats good.  I have set the settings like in the attachment. I'm starting to wounder if the wiring is wrong somehow.

[chriscroko]

In the field for "port", add /dev/RS485

That works for mine. Unsure if this is different for each version.

[admin]

Maybe the port got damaged? Have you tried switching to RS485-2?

[Evens]

Hi,
I will try to switch to RS485-2.
Tried to add text to Port as suggested, but nothing changed.

BR Even Sundgot.

[admin]

For LMs with 2+ RS-485 ports the naming is /dev/RS485-1, /dev/RS485-2 etc.

[Daniel]

Correct port naming can be checked in System Config->Status->System status-> Serial ports

[Evens]

Hi,

I did some testing today, and connected directly to the motherboard of the HVAC. 
i ran a scan with no luck. but when i ran a RTU read test. i got an reply, but not the one i wanted.

Any idea? do i have the connection correct now?

BR Even Sundgot.

[Evens]

Hi,

Any idea anyone? 

BR Even Sundgot.

[admin]

See this thread on how to run modbus script with debug enabled and post the results: https://forum.logicmachine.net/showthrea...ug#pid8457