Hi

I´m new to Modscan and i´m trying to get my pc to cummunicate with a Danfoss ECL 310 comfort panel but can´t get it to work. Im using a USB to RS485.

I think i have set the ECL 310 correct up, here are the settings. and the wirings should be correct.






Modscan settings are:
Baud rate: 38400
Word Length: 8
Parity: Even
Stop Bits: 1
Protocolo selections: Standard RTU
Device ID: 1

I have tried to pull the modbus address via Modscan but can´t get it to respond.
The PNU for "Modbus address" is 38, that should be a decimal value of 56, and i put 57 as an address in modscan (have also tried 55,56)



Any idea what im doing wrong?

 

Check your wiring. There is no agreed upon standard for the polarity of terminals labeled "A" and "B". You may need to swap your + and - wires. Also make sure you have a 3rd wire for signal reference connected between your USB to RS-485 adapter and the ECL's "S. Gnd" terminal.

What error message are you receiving in ModScan? If it's a timeout, then the problem is either your wiring or the baud rate/parity/stop bits/device ID (a.k.a. Modbus address) settings. If it's a different error, then you have successful communications, you're just probably asking for the wrong register or using a function that is not supported by the device.

 

I get the timeout error. I will go and try your suggestions and see if it helps, I have also not connceted the 3rd wire, will also do that.

I will report back the results

 

1. Are you on the right virtual COM port for the USB/485 converter? Check Windows' Device Manager > Ports and select the right COM port in Modscan's Comm setup.

2. What is a PNU?

are you sure 38 is hexadecimal?

 

Yes im sure I have select the right com port.

PNU stands for parameter number, no Im not sure it's hexa decimal, cant find anything about it in the manual, but I will try both

 

Apparently PNU stands for Parameter NUmber according to the communication manual I was able to find (https://www.manualslib.com/manual/1575268/Danfoss-Ecl-Comfort-210.html?page=25#manual).

From what I can tell, it seems the PNU's are in decimal and may be 0-based. So to read PNU 38 in ModScan, you would need to enter 39 in the Address field (since ModScan uses 1-based addressing).

 

Your PC is connecting to only one ECL 310, correct? Otherwise you'd likely have a conflicting default Slave node ID addresses.

 

Your PC is connecting to only one ECL 310, correct? Otherwise you'd likely have a conflicting default Slave node ID addresses.

Yes it only one ECL, i will try all of your suggestions when I get back to work tommorow.

 

1. ECL 310 Modbus Manual here:

https://assets.danfoss.com/documents/latest/206108/AQ074886472234en-010602.pdf

2. Any reason you're running Modbus RTU over 485 instead of using Modbus/TCP over Ethernet?

3. biasing
The 310 has internal termination and polarization/biasing. Their implementation is classic, see networks in Fig 4-2 on page 8 pdf.

Section 6.3 (page 14 pdf) claims biasing is necessary for 485 network, even though the biasing/polarization optino is by default, disabled. Very nice feature, but most 485 buses manage to run with short cabling, a Master and single slave, without biasing applied. It looks like biasing has to be implemented with the ECL software?

4. section 7.5 Communication Example

Important: PNU are one-based, with example of conversion to a hex address: PNU -1 = 0x whatever

So use the PNU number directly in Modscan for a register address, because Modscan uses one-based.

5. example network and PNUs, pg 49 pdf.
I'm not sure what the mode and status tell you, but they're apparently the variables of interest.

 

Wrong baud rate will cause a Time-out.
Presumably you have the ECL software? You should probably check and confirm the baud rate at PNU 38.

from the manual:
6.2 RS-485 Baud rate
The baud rate for the RS-485 bus can be changed by writing 9 (for baud rate 9600), 19 (for baud rate 19200) or 38 (for baud rate 38400, this is default) to PNU 39 via Modbus. Attempts to write any other values are rejected.

All devices on a network must have the same baud rate.
The ECL menu for changing the baud rate was not included until ECL software version 1.30 so for previous versions it could only be changed through communication.

 

1. ECL 310 Modbus Manual here:

https://assets.danfoss.com/documents/latest/206108/AQ074886472234en-010602.pdf

2. Any reason you're running Modbus RTU over 485 instead of using Modbus/TCP over Ethernet?

3. biasing
The 310 has internal termination and polarization/biasing. Their implementation is classic, see networks in Fig 4-2 on page 8 pdf.

Section 6.3 (page 14 pdf) claims biasing is necessary for 485 network, even though the biasing/polarization optino is by default, disabled. Very nice feature, but most 485 buses manage to run with short cabling, a Master and single slave, without biasing applied. It looks like biasing has to be implemented with the ECL software?

4. section 7.5 Communication Example

Important: PNU are one-based, with example of conversion to a hex address: PNU -1 = 0x whatever

So use the PNU number directly in Modscan for a register address, because Modscan uses one-based.

5. example network and PNUs, pg 49 pdf.
I'm not sure what the mode and status tell you, but they're apparently the variables of interest.

Not there is not any reason I´m using Modbus RTU over 485 instead of using Modbus/TCP over Ethernet, I´m just trying to get better knowledge how everything works.

I tried to flip over the A - B connection and wire the ground, and now it´s communication with Modscan

 

Wrong baud rate will cause a Time-out.
Presumably you have the ECL software? You should probably check and confirm the baud rate at PNU 38.

from the manual:
6.2 RS-485 Baud rate
The baud rate for the RS-485 bus can be changed by writing 9 (for baud rate 9600), 19 (for baud rate 19200) or 38 (for baud rate 38400, this is default) to PNU 39 via Modbus. Attempts to write any other values are rejected.

All devices on a network must have the same baud rate.
The ECL menu for changing the baud rate was not included until ECL software version 1.30 so for previous versions it could only be changed through communication.

I tried to flip over the A - B connection and wire the ground, and now it´s communication with Modscan.
The Baude rate is set to 38400