MKS 1579A, Инструкция по эксплуатации

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1579A/579A Chapter 10: Maintenance
69
Troubleshooting
Symptoms Possible Cause Remedy
No output or overrange at zero
(after warm-up) Improper cable
Valve override function applied
(Mass flow controller)
Electronics malfunctioning
Check cable for type
Disconnect / disable valve
override
Return for service
Unit indicates a negative flow Unit installed in gas stream
backwards Reinstall unit in proper flow
direction
Controller does not track set
point. Improper zero adjustment
Improper grounding(s)
Zero meter output
Check all ground connections.
Check signals, if possible
directly at the unit’s connector
Controller does not function Electronics malfunctioning
Valve sticking, clogged,
contaminated, corroded.
Shutoff valve upstream or
downstream closed
No inlet pressure
Return for service
Check compatibility of the
process gas with materials
wetted (corrosion is typically
also visible inside the process
fittings)
Readjust the valve (return for
service)
Open shutoff valve first, then
apply again setpoint to the
unit.
Regulate inlet pressure
Oscillation Supply pressure unstable, e.g.
defective pressure regulator.
Supply pressure too high
PID parameters not optimized
Check manufacturers’
specifications
Reduce upstream pressure
Profibus version only:
Optimize parameters (support
kit DMC-SUPPORT-ANA
required
→
Chapter 2)
Excessive closed conductance Inadequate valve preload
Valve seat elastomer damaged
Readjust the valve (return for
service)
Check compatibility of process
gas with seat material
Replace or change valve seat
elastomer (return for service)
Unit does not achieve full flow Upstream pressure too low
Excessive valve preload
Valve seat disc damaged, e.g.
swollen
Increase upstream pressure
Readjust the valve
Check compatibility of process
gas with seat material
Replace or change valve seat
elastomer (return for service)
Table 2: Troubleshooting