MKS MKSINST IE1000A, Инструкция по эксплуатации

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Chapter Four: Maintenance and Troubleshooting Troubleshooting
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MFC flow output matches
programmed setpoint but actual
independently measured gas flow
exceeds allowable accuracy error * Actual process gas does not match
current gas instance for MFC
* Low vapor pressure gas has
condensed in the upstream process
line
* Contaminated thermal flow sensor /
bypass combination
* Verify actual process gas in use matches
programmed gas instance in CONFIG mode
of diagnostic interface
* Verify ambient temperature exceeds
saturation temperature for the process gas at
measured supply pressure by at least 10
degrees
* Verify performance of another known good
MFC within same panel to validate standard.
If readings are acceptable with new MFC,
thermal flow sensor / bypass combination
may be contaminated.
Return MFC for repair service per
instructions above
MFC flow output matches
programmed setpoint at higher
flows but will not go to zero * Improper zero of MFC
* Inlet pressure too high
* Contamination / particles trapped
between valve plug and orifice
* Create known zero flow condition per SEMI
approved procedure and re-zero MFC to
remove offset
* Verify normal operating pressure differential
is within design specification listed in
Appendix A
* Provide valve CLOSE override command
and verify flow is within closed conductance
specification listed in Appendix A.
Return MFC for repair service per
instructions above
MFC transient response shows
large overshoot on changes in
setpoint OR respondes slowly to
changes in programmed setpoint * Actual process gas does not match
current gas instance for MFC
* Inlet pressure too high
* Inlet pressure too low
* Improper control parameters
* Verify actual process gas in use matches
programmed gas instance in CONFIG mode
of diagnostic interface
* Verify normal operating pressure differential
is within design specification listed in
Appendix A
* Verify normal operating pressure differential
is within design specification listed in
Appendix A
* Contact applications engineer for assistance
prior to returning unit for service and repair.