Modbus Register Map for Temp/Humidity Sensor

Hi there, this is my first post. As background, I’m an engineer working on a greenhouse project with a Modbus control system of our own design. We develop on the MacOS platform so we don’t have access to the controllers mentioned here or the .exe software downloads. We will use solely the Modbus capabilites of your sensors.

My first post is about further definition of the Modbus registers, over and above what is on this data sheet:

We have received the sensors and I think we have discovered some missing information and also a couple of errors. I post this as interest to the rest of the community, and perhaps Temco will confirm my findings.

Here we go:

  • Software version (register address 4) is perhaps two registers (4 and 5) for software version. This is supposition based on other devices, the documentation lists only register 4.

  • Register 7 is undocumented in the PDF but perhaps is product model, in my case, the duct sensor reports a value of 90. This can be useful in our code in determining what device we are talking to if confirmed.

  • Register 11 is undocumented in the PDF but for other sensors, this register is used for MODBUS_ADDRESS_PLUG_N_PLAY, unknown if this is the case for the duct sensor.

  • Register 15 is undocumented in the PDF but has been confirmed by us to be baud rate.

  • Register 16 is undocumented in the PDF but for other sensors, this register is MODBUS_UPDATE_STATUS. If so, this could be important for reverting to default config, etc. based on the description of what this register does in other products.

  • Register 18 sets the temperature range of the device. It would be good to get confirmation that all temperature-related registers are signed_int so that negative temperatures are correctly represented. The documentation in the PDF is not specific on this point.

  • Register 19 lists four possible values of 0, 1, 2, 3 but our sensor reports a value of 10. It would be good to get confirmation on the use of this register and the possible values.

  • Registers 21, 22, 23 are undocumented in the PDF, but these are most likely protocol setting, parity and stop bits. We will test this shortly but we assume this is the case. Any confirmation is appreciated.

  • Register 37 is listed in the PDF as a potentiometer R2 offset value, but we have discovered that this register tracks temperature in SI units (deg C). We assume this is an error in the PDF document.

  • Register 41 is dew point in SI units, the unit system is not mentioned in the PDF.

  • Register 42 is enthalpy in SI units, the unit system is not mentioned in the PDF.

  • Register 44 is absolute humidity in SI units, the unit system is not mentioned in the PDF.

  • Registers listed above, 37, 38, 39, 41, 42, 44, 45 all report a number 10x the actual value (to give you a decimal point). It might be good to include in the PDF that you divide by 10 to get the actual value.

  • Register 51 reports as a test switch to have the analog output values show up in registers 52, 53. We have tried to test this by setting register 51 to ‘1’. This seems to do nothing. Since it is documented in the PDF, we assume this is useful and would like information on how to use this function purely through Modbus.

  • There are many other registers that report values but are not documented. If there is more extensive developer documentation on all registers, usage, values and defaults, that would be useful.

I will say that this is our first exposure to Temco products and we find the build quality and functionality to be very good. We are very happy with selecting these products. It would be nice to have more robust developer documentation that does not rely upon Temco control systems or Windows software, but we have not found major impediments. This post is mainly for the benefit of the community and to get some confirmation of the issues described above from Temco.

Cheers, Ano

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I have to confess we have let the PDF documentation fall behind, we will get the team to update the documents. The main effort with the register list has shifted to keeping the database up to date, it can be opened in any general macintosh database program such as Filemaker, Knack or Access. You could use Virtualbox or Bootcamp to run an instance of T3000, after installation the file can be found here:

C:\Program Files (x86)\T3000\ResourceFile\RegistersListDB.mdb

The register viewer tool is handy for integrating since you can jump back and forth from the UI to the register list and see the values change as parameters are adjusted in the UI. Once you are familiar with all the settings and registers you can move on up to your particular environment.

Thanks for the quick reply Maurice. I will see if I can extract the database and use it as the main documentation source.

Cheers, Ano

And give VirtualBox a try, it will save you a lot of time to get started with that T3000 and the register viewer tool.

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