Jumo Modbus Addresses


I have a Jumo Logoscreen 500 cf and am trying to use your modbus driver to get the temperatures. Their documentation is attached - I’m after the values in analog channels 1 - 6 (0x0035, 37, 39, 3B, 3D and 3F). I’ve tried using the addresses as well as directly in the tag ([Device_Name]1.HR53 for 0x0035, [Device_Name]1.HR55 for 0x0037, etc.) and the numbers still don’t look right.

I’ve gone through your modbus addressing documentation and I’ll be honest that I don’t quite understand when to use BCD or some of the other options.

Thanks in advance for any help,

According to the docs the datatypes of the addresses you’re trying to read are floats, so you need to use [Device_Name]1.HRF53 when addressing them.

I had also tried that at one point and the value jumps around randomly - from 0 to numbers that have more commas than I can count.

Am I correct in that the hex values need to be converted to dec?

Yeah, I think you are supposed to be converting them. Go into the advanced properties on device settings and try enabling the ‘reverse word order’ setting. Then see if the values you get using HRF make sense.

Yes! It worked - thanks so much for the help and the quick reply!

No problem. You need to be aware that the ‘reverse byte order’ property affects all 32-bit values that the driver reads, not just floats. So you better hope they decided to use the wrong word order for any 32-bit integer values as well as floats (if they even provide any 32-bit integer values, anyway…)

Hi, I am running into a similar problem, I am trying to read values from a Jumo Dicon touch. The values that I am after are (0x122D,0x122F,0x123D and 0x123F), these are also float values, but I am not getting any data into Ignition. I am using the path: [Device_Name]1.HRF4653 for 0x122D.

Does the ‘.1’ before ‘HRF’ refer to the Channel? I am also trying to read from channel 1.

Thank you in advice for any hints!


In Modbus terms it’s the unit/slave ID. I don’t know if that translates to channel for your device.

Try enabling Zero-based Addressing and/or Reverse Word Order in the settings for this Modbus device in Ignition.

Thank you Kevin,

I checked the unit ID of the device and it seems to be correct as 1, I also tried enabling Zero-based Addressing and/or Reverse Word Order but in Ignition I still get ‘Bad_NotConnected: The variable should receive its value from another variable’.

Any ideas?

Use a 3rd party Modbus client to verify you can connect and get data.

If that works, use Wireshark to capture traffic of each software and we’ll compare the difference.

I finally solved it. I used a third party modbus client as Kevin suggested, it turns out that with this specific Jumo device the unit ID is set to 255, in the software I would see a different unit ID hence the confussion.

Thanks a lot Kevin!