I've got an industrial controller that takes an N-type thermocouple and scales its range (0-1300°C) to a 0-10V DC output signal. (For reference, the module is this: https://www.status.co.uk/product/signal-conditioner-temperature/)
The 0-10V signal has 200Hz noise coupled to the output. I would like to remove the noise.
I've tried using a low pass filter but it does absolutely nothing. The values of components used for the low pass filter are R = 787 ohms and C = 1uF giving me (roughly) a 200Hz cut-off frequency.
The 0-10V signal is fed directly into a op amp in a unity buffer configuration (the op amp is an Analog Devices ADTL084ARUZ.) The signal is then passed into an acquisition system which is sampling the signal 10,000 times a second.
There are no other noise issues on any of the other analogue input signals for this system and I've changed the acquisition for an equivalent system so I know there are no issues with the acquisition itself.
The signal travels from the signal conditioning module to the acquisition via a screened 2 core cable over a distance of about 3 metres.
What can I do to remove the noise?
I appreciate I could make the capacitor bigger therefore making the reactance lower and creating a quicker path to ground for the coupled noise signal. I suppose I could change the filter for an LC filter or a band pass filter as well.
Additionally, what is the best type of capacitor to remove these types of noise issues? I'm currently using a ceramic capacitor but I've also tried MLCC and electrolytic just to see if they would have a different effect but they also did nothing.