Phidgets Forums

Hey!

We've got a device with three RTDs and lately we've been getting a 'Saturation Detected' error with one of them. These are two wire and yes I've followed the two wire connection method as described on the TMP1200_0 user guide.

Phidget TemperatureSensor Error 4105: Saturation Detected.

I should note that this isn't a problem with specific boards/RTDs. We've got temperature controls for location A, B and C and it's always location C that has this problem. We've seen the same thing in other units so it's not specific to any one device.

The RTD boards are all connected to the same VINT Hub.

Has anyone else seen this come up with multiple RTDs? We never had this problem until we introduced a third RTD board into our devices.

Saturation errors typically indicate either a bad connection of the sensor in the terminal blocks, or the sensor is seeing measurements outside it's specified operating range. If you have double checked the connections and the expected measurements are within spec, is location C a particularly electrically noisy environment? What do you see if you use a multi-meter to measure RTD C?

I've noticed saturation mostly with bad connections as well and we've taken measures to make darn sure that they're solid. One of the reasons I don't think it's a bad connection is because we've never had issues with locations A/B. Temperature also doesn't seem to play a role as this problem has shown up at room temperature.

Location B is in very close proximity with location C. The sensors themselves aren't in a noisy environment though the cables do share routing with a number of other connections, including low voltage power. That being said the routing of locations B/C are shared and we've never seen an issue with location B. The RTD boards themselves are all located in the same area is well, stacked on top of one-another.

What's crazier is in one particular unit all locations were functioning just fine, then one day location C magically started exhibiting this issue that we've seen on other units.

My first thought about stuff like this is that it's a software issue, but I've set up some configuration that allows me to swap RTDs and VINT hub ports and the board/RTD from original position C always give me the same result no matter what I do. Worse is that the boards are buried in layers of manufacturing steps so to do something like measure them with a multi-meter I need to disassemble quite a bit of parts. C'est la vie.