MKS P9B, Инструкция по эксплуатации, Страница: 94 / 112

Chapter Eight: Troubleshooting Troubleshooting Chart
84
MFC shows 0 flow when
given setpoint (cont’d) MFC clogged sensor Run MFC diagnostics. Verify MFC
inlet pressure, check valve current
for open valve condition and check
for gas flow downstream of MFC. If
flow present, possible clogged
sensor
MFC control circuit failure Run MFC diagnostics. If error
results, contact MKS service center.
MFC shows output flow >
FS (overrange) MFC valve full open Check valve current for maximum
condition
Pressure drop across MFC is
greater than specification Measure upstream pressure &
downstream pressure. Compare to
specification.
Faulty valve control
circuit/calibration Run MFC diagnostics using Ethernet
GUI
Possible contamination in valve
assembly Cycle-purge MFC to clear suspected
contamination
MFC output signal does
not match setpoint Contamination Check for partial block orifice or
sensor. Cycle purge MFC to clear
contaminant
MFC valve full open Check valve current for maximum
condition
Inlet pressure too low Increase inlet pressure
Outlet pressure too high Decrease outlet pressure
Flow signal is not properly
grounded. Check for ground loops.
Control electronics failure,
sensor failure Run MFC diagnostics test
MFC output signal
oscillates Inlet pressure oscillates Check for faulty regulator
Inlet pressure too high Lower inlet pressure
MFC nameplate gas not same
as actual gas Check for programmed gas using
Ethernet GUI or digital interface.
Reprogram as necessary
Faulty control circuit Run MFC diagnostic test.