4-3
SLA7900 Series
Installation and Operation Manual
X-TMF-SLA7900-MFC-eng
Part Number: 541B022AAG
August, 2009
Section 4 Maintenance &
Troubleshooting
3.
Setpoint is below minimum. MFCs may have a settable low flow cutoff
for the setpoint command. If setpoint is below this value, then MFC will
not attempt to control.
4.
Clogged sensor tube. If the MFC sensor tube is clogged, the flow
signal will be very low or zero while the actual flow will be at the valve’s
maximum rate.
Flow signal matched setpoint but actual flow is not correct.
5.
Clogged restrictor. If the MFC restrictor becomes clogged, a much
larger portion of the flow stream will pass through the sensor rather
than going straight through the restrictor. The symptom of this
condition is a substantially reduced actual flow with a flow signal which
matches the setpoint.
Flow rate in excess of 100% at zero setpoint.
6.
Valve Override pin set to open. If valve override (VOR) pin is active,
the valve will be forced open or closed. Set this pin to its normal level
before setting a setpoint.
Flow/Flow signal ‘unstable’.
7.
Model SLA7950 Series MFC performance is tuned during calibration
at the conditions specified on the order. If the conditions in use (inlet
and outlet pressure, temperature, attitude, gas or mixture type) are
different or become different over time, the MFC may not perform as it
did when it left the factory.
DeviceNet Version Only
Failure of the flow rate or flow signal to achieve the setpoint.
8.
Specifically for a DevcieNet MFC, there may be problems associated
with the network communication link. One common problem is due to
data type mismatches of the Input\Output (I\O) Assemblies. For proper
communication over the DeviceNet network, the MFC must be set up
with the same I\O Assembly as the network master. Confirm these I\O
settings are correct. Note this information and all other detailed
DeviceNet information is available in the DeviceNet supplement
instruction manual, X-DeviceNet-MFC-eng,
Part Number 541B059AHG.
Questions
Analog Version
What is the purpose of the LED on top of the SLA7900 Series MFC?
The LED on top of the MFC should normally be lit GREEN. This signifies
the MFC is in proper working mode. If the LED is lit RED this signifies a
critical fault has occurred in the MFC. Please contact the factory for
instructions.
