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Ambient air temperature sender

Matthew Herzig 3 months ago updated by Gustav Widén (System support) 2 months ago 3

I thought this would be easy to find but having no luck.  I have a request to read the outside ambient temperature on the MD4-7 and not having any luck finding anything to do this with.  If all else fails the standard ones I have used for hydraulic fluid might work in a pinch but unsure how accurate that would be.  If this is something anyone has any ideas on I would appreciate any feedback.

Any sensor that gets you a 0-5VDC input to read will work.

Not sure of any for ambient air specifically, but any RTD-based sensor should work.

You just have to configure the scaling to work with your sensor's datasheet.

TU4105 - Temperature transmitter - ifm for example

Thanks for the reply and the vendor link.  I am used to the GS version (been using it for 8 years in the hydraulic tanks of over 1000 tracked Carriers) that has the same range as that one and was told it may not work correctly as an air ambient sender.  All the customer wants is outside ambient on the display so even if it does not react quickly that is fine.  Any of the ones I have seen specifically for ambient look fragile anyways!  This will be hanging out on the external control box so will be exposed to the elements.

You can use any NTC-sensor with a suitable resistance connected between Vref+ and VIN.

The VIN-inputs has 38kOhm pulldown resistors, so you get the voltage divider for free.

Just select a resistance/characteristic of the NTC that provides a decent resolution in the temperature range you want to monitor (roughly 38kOhm in the middle of the temperature range) and make a calibration table to convert voltage to temperature.