RS485 command recognition code fuel sensor

[rvoosterhout]

Hello,

We are using our Loxone system in our data center and now I want to connect a generator fuel sensor to our RS485 extension. The sensor transfers 3 parameters based on characters (ASCII code). I would like to know how to set up the CRC to get the value of N.


Kind regards,

Rick van Oosterhout

[Tico]

Hi Rick. Welcome to the Forum. I'm not sure if I understand the situation completely. I assume the screenshot is from some interface connected to the RS485 bus. Can you provide a screenshot of the Loxone RS485 Monitor when connected to the same bus (and preferably at the same time and values as a screenshot of the interface above)? Just use Checksum as None initially.

Comparing the two data streams will enable a means to develop the Command Recognition in Loxone.

[rvoosterhout]

Hi Tico,

I currently don't have the fuel sensor yet. I wanted to know if it was going to work with Loxones rs485 extension prior to buying the sensor.

[Tico]

I can't answer that without details on the fuel sensor: brand, model, web-link, installation manual...anything?

Generally the RS485 Extension is fairly versatile for reading most RS485 data streams. In the absence of any specifications for the data stream, you can anticipate a challenging learning curve to interpret the data. That's where a comparison of a screenshot like you posted is above is essential to compare with what Loxone reads.

[rvoosterhout]

It's a Dut-E 485 Fuel level sensor (https://e-shop.jv-technoton.com/product/dut-e-485/).
This is the only information in the manual from what I can find regarding the data transfer:

ASCII text protocol (American Standard Code for Information Interchange) is used for automatic data transfer by DUT-E 232/485 digital fuel level sensors, according to TIA/EIA 232-F and ANSI/TIA-485-A standards.
The data transfer interval is set within the range 1…255 s (1 s by default) using Service DUT-E software (see figure H.1).
ASCII text protocol is a code for interpretation of decimal digits, Latin and national alphabets, punctuation characters and command characters. The protocol allows to convert numerical values (names) needing description into simple letter characters. 1) According to ASCII text protocol, DUT-E 232/485 sensor transfers the following three parameters in the form of characters (ASCII code) at set intervals (see figure H.2): F – value of the current of the sensor measuring generator frequency, Hz; t – value of the sensor temperature, °C; N – current sensor readings in units preset using the service software (conventional units/mm/liters/%) (see figure H.1).

So it looks like it's sending a line of text every second on the bus. Attached is the manual. Page 114 talks about data transfer.

Kind regards,

Rick

[Tico]

I can't see any reason why it won't work with Loxone. The manual you linked to has a YouTube video that goes through the installation on Page 116. There's a lot of calibration steps to set up the meter. Are you going to purchase the SK-DUT-E Service Adapter? The Service Adapter appears to be a simple RS232/485 to USB adaptor with Windows software. It's not very clear whether the factory default state of the meter sends the ASCII text. To change that setting, the Service Adapter is required and appears very expensive at €248.60!

The Windows software can be downloaded here -

https://jv-technoton.com/software-firmware/?utm_source=offline&utm_medium=manual&utm_campaign =dut-e_eng

Download and install the software (change the language to English), load the Default profile and you will see that the 'Automatic transmission mode' is set to off. Which suggests the Service Adaptor might be needed for the initial setup. It would be worth emailing them to find out what the 'Automatic transmission mode' is set to in the factory default state.