Jazz PT15 - problem with PT1000

[Pedro]

Hi all,

I've been using a Jazz PT15 with 3 PT1000 sensors connected (measuring hot water at a boiler room) very well. I recently installed another PT15 in another room but this time the measurements are very unstable: temp shows correctly (40ºC for example) but jumps every few seconds to 36ºC or 45ºC...a huge gap! I tried the "high" filter, but inputs keep fluctuating a lot. I tested the sensors with another application and they are ok. PLC is grounded.

The only issue is that sensors cables run very near other 220V cables May those cables produce noise to the sensors? (I have done that before without any trouble, though).

Am I forgetting something / doing something wrong regarding PLC connections?

Any help will be highly appreciated!!

thanks in advance

Pedro

[Emil]

Hi Pedro,

definitelly the high power cables along with sensor ones emit noise and can be the reason for the problem. But before continuing and taking special care, can you make a simple test - connect the sensor with shortest posible cable direct to the controller and keep it in the air. Is the signal stable now?

Another one possible cause for the problem - where the sensors are located? Are the boilers grounded by themselves? Is thhe ground point the same as the one of the controller?