Micromod MOD: 30ML and Modcell Maintenance for 2001N, 2002N, and 1800R - Manual (Page 141)

Grounding and Wiring
Guidelines for MOD 30ML
To avoid associated diagnostic
errors and shutdowns
Symptoms:
Faceplate communication error, faceplate FAILURE error, analog input diagnostic errors, instrument
shutdowns occurring on a regular or intermittent basis.
Applies to:
MOD 30ML
Explanation:
The MOD 30ML controllers require good signal and power grounding for proper operation. A very large
percentage of the field problems reported are due to poor grounding and wiring practices. This is
especially true when the MOD 30ML is installed as an upgrade to pneumatic instrumentation, where no
grounding was required, or to the old MOD 30 series instrumentation, which had different grounding
requirements than current technology.
Improper grounding can cause noise or static discharges on the analog inputs and power lines. This can
show up as faceplate communication failures, analog input failures, and instrument shutdown errors.
Solution:
It is important to check all signal and power grounding and wiring, following the recommendations
provided below.
Power Safety / Protective Ground
• The green ground lug on the MOD30ML is where the power safety or protective ground is to be
connected.
• No other connections are to be made to this lug.
Topic: MOD 30ML/Modcell Technote: TNML1001-1
MicroMod Automation, Inc. Rev. 3, Feb-2005
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