Issue
Fluctuating temperature readings where they jump up to +327 randomly.
Product Line
Andover Continuum
Environment
- Continuum controllers
- i2866-V
Cause
Readings like that are usually caused by wiring or power issues. There was also a Firmware fault that caused this in an old version of the i2866-V Firmware.
Resolution
Confirm the following wiring considerations:
- That your input and output cables shield is wired to Earth ground at one end of the run only (preferably the controller chassis).
- That your controllers power supply is earthed on the secondary side of the 24vac transformer to ensure a proper controller ground to Earth.
- Confirm that the power supply is not being shared with any field devices, especially field devices feeding inputs back into the controller.
One way to troubleshoot if it is a cabling or controller problem is to replace the sensor cable with a 10K ohm resistor. See Temperature inputs not reading the correct value for details.
Also, in i2866-V controllers with firmware versions less than v3.501049, temperature inputs could randomly go to +327 when Analog Outputs were changing value frequently. Uprev your controller. See TPA-BOST-09-0007.00 for details.
