Is there any way to change the modbus data format from float32 to sw. float32?

[chrislimk (Chris Lim)]

I’m using the modbus integration to pull sensor values from my EV charger, however i found that all the float values displayed were not accurate.
For example register 358 is showing a value of 1.69 instead of ~0.38

Bit of digging with a modbus scanner revealed that the value should be formatted in “32bit sw. float”
http://www.protoconvert.com/Portals/0/RadzioModbusMasterSim/RMMS-v0.1.6/ModbusMasterSim-v0.1.6.zip

ps: the value here is pulled during the trickle charge stage and hence below 1.

Configuration

modbus:
  - name: EVSE
    type: tcp
    host: 192.168.0.X
    port: 502

    sensors:
    - name: EV Charger - Current Charge Rate
      address: 358
      unit_of_measurement: kW
      slave: 255
      data_type: float
      scan_interval: 2
      precision: 2

[tom_l]

I’m no expert on Modbus but I think the registers are only 8 bits wide. So for a 32bit word you have to set the count option to 4. You may also have to configure the swap option.

[chrislimk (Chris Lim)]

Thanks for the tip! I tried to set it to count 4 and it gave an astronomical value, so i tried 2 and it seems to be correct at least for the values i can read off currently. I’d be able to tell if count 2 really did it the next time i charge my car in a few days.

Current values

[chrislimk (Chris Lim)]

Update: Count 2 did the trick without any swap required.

The model I have is the Schneider Evlink Smart Wallbox, for those looking to do the same.
Built a simple dashboard and some automations to alert when the charging has completed.

[poldim]

Hey Chris,

Did your charger have spelled out modbus connection terminals? I’ve got the one below and it doesn’t appear to have anything labeling those points.

[chrislimk (Chris Lim)]

Hey Poldim, I connected to modbus via TCP/IP from an RJ45 connector. Yours look very different from mine so I suppose you must have another model. Perhaps searching the product pages or contacting your service representative might help.

https://download.schneider-electric.com/files?p_enDocType=Instruction+sheet&p_File_Name=NNZ2678201-05.pdf&p_Doc_Ref=NNZ2678201

[jbanyer (Jay Banyer)]

@chrislimk are you able to share the modbus register address mapping for the Schneider EVlink Smart Wallbox? I’m trying to get mine working too. Thanks!

[chrislimk (Chris Lim)]

Let me get back to you as I am currently away on vacation.

Here’s a small snippet to get you started

##Charge Rate
- name: EV Charger - Current Charge Rate
address: 358
unit_of_measurement: kW
device_class: power
state_class: measurement
slave: 255
data_type: float32
scan_interval: 5
precision: 2

##Charge Time
- name: EV Charger - Charge Time
  address: 31
  unit_of_measurement: s
  slave: 255
  data_type: uint16
  scan_interval: 5

[jbanyer (Jay Banyer)]

Thanks for your reply. I’ve managed to work out most of the registers, see attached.

One important thing I’m missing is accumulated charge energy (Wh / kWh), either session or lifetime.

The modbus docs for the new EVlink Pro has both of those values documented, but the register maps are very different.