S
Hi Guys,
I'm new to the world of Modbus, and I'm trying to get things working in my house. This is my setup:
- Schneider electric Homelynk (RTU master)
- HVAC systsem, 2-wire + GND RTU, ID-1
- Heatpump, 2-wire RTU, ID-8
I'm running at 19200 baud and I have successfully been running my HVAC together with the maste for a couple of months. It polls correctly and no error messages at all!
Since last week, I have tried to connect my heat pump to the bus, using daisy-chain.
But when I connect the HP, I start to get all kinds of trouble.
I can poll both HP and HVAC and get values. But the communication is very sluggish, and many of my commands to the HVAC gets lost and my error log practically spits out these errors with every or another poll;
- Invalid CRC
- Operation times out
- Response not from requested slave
Even if I haven't mapped or polling the HP, i get the above errors when polling the HVAC as long as the HP interface is connected.
If I disconnect the HVAC from the bus, but let the master still poll the HVAC, and the HP interface is connected without mapping, I still get CRC errors.
In my opinion the HP interface responds to requests that are meant for another RTU device. But according to the manufacturer there is no problem with the interface, and it should only listen to ID-8 and ignore the rest, and 2 other of his customers are running this very interface without issues. (I don't know their setup)
The cable I'm using is a KNX bus-cable, TP cable. The total length is about 30 meters approximately.
I'm new to the world of Modbus, and I'm trying to get things working in my house. This is my setup:
- Schneider electric Homelynk (RTU master)
- HVAC systsem, 2-wire + GND RTU, ID-1
- Heatpump, 2-wire RTU, ID-8
I'm running at 19200 baud and I have successfully been running my HVAC together with the maste for a couple of months. It polls correctly and no error messages at all!
Since last week, I have tried to connect my heat pump to the bus, using daisy-chain.
But when I connect the HP, I start to get all kinds of trouble.
I can poll both HP and HVAC and get values. But the communication is very sluggish, and many of my commands to the HVAC gets lost and my error log practically spits out these errors with every or another poll;
- Invalid CRC
- Operation times out
- Response not from requested slave
Even if I haven't mapped or polling the HP, i get the above errors when polling the HVAC as long as the HP interface is connected.
If I disconnect the HVAC from the bus, but let the master still poll the HVAC, and the HP interface is connected without mapping, I still get CRC errors.
In my opinion the HP interface responds to requests that are meant for another RTU device. But according to the manufacturer there is no problem with the interface, and it should only listen to ID-8 and ignore the rest, and 2 other of his customers are running this very interface without issues. (I don't know their setup)
The cable I'm using is a KNX bus-cable, TP cable. The total length is about 30 meters approximately.