0 Degree readings on RTD probe


We have two RTD probes in coolers, one with the original probe, one with a proper industrial replacement probe. Both seems to send 0 degree C readings intermittently. the sensor is transmitting. From what I could find is that this means the connection between the probe and the transmitter is lost? What explanation is there for this, we have seen this on three transmitters already.

there must be an error. the product datasheet has a list of errors.

what gateway are you using ?

node-red on edge computer
Screenshot 2024-01-11 103037

whats the value of the 8th byte. its a reserve byte.

0x20 — VBIAS Fault
0x10 — VBIAS Force- close
0x08 — VBIAS Force- open
0x04 — Over and under Voltage

@Bhaskar does this tell you what you need?

while reading the RTD value device is encountering overvoltage/undervoltage error.
@jacob @TravisE_NCD_Technica can we add a condition in the node red so that when the reserve byte is non zero it just outputs the error code and not the complete msg.

That sounds great. anything we can do to get more consistent readings from these probes?

I tested at room temp and didnt encounter this let me test at a low temp

It does not seems to happen with other probes. in fact when I moved that sensor to measure room temperature, it didn’t occur again. But it does occur with multiple RTD sensors we placed in coolers.

I am running one outside

no bad reading so far

I assume you have already checked and ruled out any issues with loose wire connections.

Hi Bhaskar,

I have. the problem actually reoccurred on that sensor, as you can see now the variations are quite large.

The only other thing that these sensors had in common is being externally powered. Is your denk model just battery powwred? Not sure if this could cause interference

mine is installed outside and powered by batteries.
can you try using batteries. dirty power can create issues.

These are placed though to retransmit signals from sensors further back from the main gateway. Eventually they would have to be powered. I may be able to set something up temporarily to test. Are you able to run yours on power to see if you notice any changes? We’ve determined that it wasn’t the temperature affecting the readings so it could be inside.