Issue
The Universal Input real-time values on a MNL-800 (or Microzone II) are fluctuating unrealistically. They rise, peak, drop, valley and then start over again very quickly. It is similar to an AC wave pattern.
It is happening with all the inputs no matter their configuration.
Product Line
TAC IA SeriesEnvironment
- MNL-800
- Microzone II (Network 8000)
Cause
When an actuator is interfaced with a MNL-800 (or MicroZone II), and the UI cable shields are connected to earth ground (the SHLD terminal), the shield has a common mode AC potential that couples to the UI input. Only a very small signal (UI shield to signal common) is needed to result in objectionable UI signal fluctuation.
Resolution
Connect all drain shields on UI inputs to UI common (C terminal).
Read additional solutions and a more descriptive cause in Technical Bulletin 01-36.
