Electromagnetic Interference?

[[email protected]]

I have a problem about a Cryo temperature monitor. The probe's
capability is to monitor -95C to -1C.
There are spikes of two probes for monitoring -20C deepfreezers, while
the temperature is stable indeed. Are there any Electromagnetic
Interferences?The cables are well earthed. How to resolve this problem?
Thank you very much!

 

[Jumpster Jiver]

I have a problem about a Cryo temperature monitor. The probe's
capability is to monitor -95C to -1C.
There are spikes of two probes for monitoring -20C deepfreezers, while
the temperature is stable indeed. Are there any Electromagnetic
Interferences?The cables are well earthed. How to resolve this problem?
Thank you very much!

Sounds like a temperature-sensitive or other type of loose connection
somewhere between the sensor tip and the monitor.
Does it change or occur more or less if you flex the wires or move them
around while monitoring?
Do you have another probe to compare it with?

 

[GregS]

Sounds like a temperature-sensitive or other type of loose connection
somewhere between the sensor tip and the monitor.
Does it change or occur more or less if you flex the wires or move them
around while monitoring?
Do you have another probe to compare it with?

I just made one of those, had to construct a copper constantine probe.
A new probe should be tried.

greg

 

[[email protected]]

Well, thanks Jumpster and greg. There are 4 probes and the other two is
to monitor -80C deepfreezers.
I have changed the four probes each other.Temperatures of -80C are very
stable whit whichever.
Yesterday I put the probes into aluminium tubes.Also I rechecked the
connections. Till now the spike doesn't occur. I will keep an eye on
it.Thanks again!

 

[**THE-RFI-EMI-GUY**]

Is anyone using a cellphone or Nextel near the equipment?

 

[[email protected]]

No. Sometimes the spikes occured in the midnight.

 

[Yong Chen]

Ohhhhhhh, The spikes occured again after I reinstalled the probe.
Maybe I must check the connection again.