Hello
I have a few units of this device (https://store.ncd.io/product/industrial-iot-wireless-rtd-temperature-sensor/) 6 of them to be more precise. That where ordered as this id but came a different hardware. Like the picture bellow
I need to know why it registers 0ºc or 32F when the probe is at - 80ºc
What is wrong?
Some frames for help:
7e0019900013a2004261aca3fffec27f000403fce900271e0000000059
7e0019900013a2004261aca3fffec27f000403fcea00271e0000000058
Thanks in advance
Hi Cesar, sure, let me ask you: Is this issue occurring with only one of your RTD sensors?
Could you please check if the RTD cables are in good condition? In your picture, one of the cables appears slightly bent, and I want to rule out the possibility of it being broken internally.
Thank you.
The condition you see is how we got them from the factory. Its very strange this one does not have a “plug/socket” so we can change easily the PT100 resistor.
By the way, all of them where reporting ambient sensor, then when all where placed in different places of -80ºc they all stopped working.
And my 2 cents to the firmware team, when sensor is disconnected it should report something out of scale and not a real possible value.
Any info on the frame that informs us if the sensor is disconnected or not?
Hi @cesararaujo Yes, the sensor packet includes a fault status byte, which is located at the 8th byte of the data payload:
7e0019900013a2004261aca3fffec27f000403fce90027[1e]0000000059
7e0019900013a2004261aca3fffec27f000403fcea0027[1e]0000000058
We have updated our library to decode these status codes and display the specific error. These errors include:
Please note that this decoding applies to firmware version 6 and above. I am currently checking with our firmware team to see if these fault codes also apply to your current version (v3).
temperature: 0 and reserved byte is: 1E.What happens if you return the sensor to an ambient temperature location? Does it begin transmitting correctly again?
For testing purposes, could you try powering the sensor using only batteries, observe and share the behavior in both the ambient and -80C locations?
Thanks.
Hi @cesararaujo I’m checking the issue with our hardware team, let me ask you, what components are exposed to -80°C environment? is it just the PT Sensor probe or the white box as well?
Thank you.
Hi @Eduardo_Mtz
Just the PT100 and part of the cable are in the freezer, the box is safe outside at room temperature.
They are powered only with battery, no external power applied.
Asked to put them at room temp and they did work correctly.
From the log of our service we extracted this for one sensor. Were we can clearly see 32F and then suddenly weird things happening.
Remember that this was the firmware fixed where the encryption key was wrong, the msb and lsb where swapped.
2025-12-22 06:16:32 - 7e0019900013a200425247c3fffec27f000403fcc200271e00000000d4.
2025-12-22 06:17:31 - 7e0023900013a200425247c3fffec27f0004000000002701464c5955590f0000003c000681ae99.
2025-12-22 06:18:32 - 7e0019900013a200425247c3fffec27f000403fcc300271e00000000d3.
2025-12-22 06:19:32 - 7e0019900013a200425247c3fffec27f000403fcc400271e00000000d2.
2025-12-22 06:20:32 - 7e0019900013a200425247c3fffec27f000403fcc500271e00000000d1.
2025-12-22 06:21:32 - 7e0019900013a200425247c3fffec27f000403fcc600271e00000000d0.
2025-12-22 06:22:32 - 7e0019900013a200425247c3fffec27f000403fcc700271e00000000cf.
2025-12-22 06:23:32 - 7e0019900013a200425247c3fffec27f000403fcc800271e00000000ce.
2025-12-22 06:24:32 - 7e0019900013a200425247c3fffec27f000403fcc900271e00000000cd.
2025-12-22 06:25:32 - 7e0019900013a200425247c3fffec27f000403fcca00271e00000000cc.
2025-12-22 06:26:32 - 7e0019900013a200425247c3fffec27f000403fccb00271e00000000cb.
2025-12-22 06:27:32 - 7e0019900013a200425247c3fffec27f000403fccc00271e00000000ca.
2025-12-22 06:28:32 - 7e0019900013a200425247c3fffec27f000403fccd00271e00000000c9.
2025-12-22 06:29:32 - 7e0019900013a200425247c3fffec27f000403fcce00271e00000000c8.
2025-12-22 06:30:32 - 7e0019900013a200425247c3fffec27f000403fccf00271e00000000c7.
2025-12-22 06:31:32 - 7e0019900013a200425247c3fffec27f000403fcd000271e00000000c6.
2025-12-22 06:32:32 - 7e0019900013a200425247c3fffec27f000403fcd100271e00000000c5.
2025-12-22 06:33:32 - 7e0019900013a200425247c3fffec27f000403fcd200271e00000000c4.
2025-12-22 06:34:32 - 7e0019900013a200425247c3fffec27f000403fcd300271e00000000c3.
2025-12-22 06:35:32 - 7e0019900013a200425247c3fffec27f000403fcd400271e00000000c2.
2025-12-22 06:36:32 - 7e0019900013a200425247c3fffec27f000403fcd500271e00000000c1.
2025-12-22 06:37:32 - 7e0019900013a200425247c3fffec27f000403fcd600271e00000000c0.
2025-12-22 06:38:32 - 7e0019900013a200425247c3fffec27f000403fcd7002700ffffc575a5.
2025-12-22 06:39:32 - 7e0019900013a200425247c3fffec27f000403fcd8002700ffffc57e9b.
2025-12-22 06:40:32 - 7e0019900013a200425247c3fffec27f000403fcd9002700ffffc59484.
2025-12-22 06:41:32 - 7e0019900013a200425247c3fffec27f000403fcda002700ffffc59483.
2025-12-22 06:42:32 - 7e0019900013a200425247c3fffec27f000403fcdb00271e00000000bb.
2025-12-22 06:43:32 - 7e0019900013a200425247c3fffec27f000403fcdc00271e00000000ba.
2025-12-22 06:44:32 - 7e0019900013a200425247c3fffec27f000403fcdd00271e00000000b9.
2025-12-22 06:45:32 - 7e0019900013a200425247c3fffec27f000403fcde00271e00000000b8.
2025-12-22 06:46:32 - 7e0019900013a200425247c3fffec27f000403fcdf00271e00000000b7.
2025-12-22 06:47:32 - 7e0019900013a200425247c3fffec27f000403fce000271e00000000b6.
2025-12-22 06:48:32 - 7e0019900013a200425247c3fffec27f000403fce100271e00000000b5.
2025-12-22 06:49:32 - 7e0019900013a200425247c3fffec27f000403fce200271e00000000b4.
2025-12-22 06:50:32 - 7e0019900013a200425247c3fffec27f000403fce300271e00000000b3.
2025-12-22 06:51:32 - 7e0019900013a200425247c3fffec27f000403fce400271e00000000b2.
2025-12-22 06:52:32 - 7e0019900013a200425247c3fffec27f000403fce500271e00000000b1.
2025-12-22 06:53:32 - 7e0019900013a200425247c3fffec27f000403fce600271e00000000b0.
2025-12-22 06:54:32 - 7e0019900013a200425247c3fffec27f000403fce700271e00000000af.
2025-12-22 06:55:32 - 7e0019900013a200425247c3fffec27f000403fce800271e00000000ae.
2025-12-22 06:56:32 - 7e0019900013a200425247c3fffec27f000403fce900271e00000000ad.
During this period its in a freezer and nobody made anything.
Hi @cesararaujo We’re reviewing the data you provided. To help us troubleshoot the issue, could you please double-check the current freezer temperature?
According to the records, the last valid recorded reading was -149.87°C. Since the lowest temperature supported by this device is -150°C, the sensor is nearing its operating limit. Could you please double-check the freezer’s physical temperature to confirm if it’s actually -80°C or lower (about -150C)?
The freezer is at -80º celcius or -112 fahrenheit.
Thanks
Can you give me a link to the protocol specification where the error of no sensor connected is detailed?
Thanks
Hi @cesararaujo Sure, for this device these are the fault status:
Reserved byte
1E --> RTD fault status (1-bit left shifted).
See Fault status responses below
Fault status responses:
0x00 -- Channel data valid
0x0F -- Channel data invalid
0x21 -- REFIN- > 0.85 x VBIAS Fault
0x11 -- REFIN- < 0.85 x VBIAS (FORCE- close) Fault
0x09 -- RTDIN- < 0.85 x VBIAS (FORCE- open) Fault
0x05 -- Over-voltage / under-voltage Fault (Any protected input voltage >VDD or <GND1)
We are currently investigating the root cause of the issue. Based on the data, it appears the RTD probe was exposed to a temperature below -150°C, which triggered the 0x0F error.
It is unlikely that this is a wiring or connection issue, as the sensors are measuring room temperatures accurately, as you confirmed. This suggests the hardware is functioning correctly, but the environment exceeded the sensor’s calibrated range.