Section 4 Maintenance & Troubleshooting
utes. In case of a controller model, adjust the setpoint to zero. Do not
connect the device to a gas source yet. Observe the output signal and,
if necessary, perform the zero adjustment procedure (See Section 3,
Zeroing Function.Zeroing). If the output signal does not zero properly,
please contact Brooks Instrument.
2. Connect the instrument to a source of the same gas used for it's origi-
nal calibration. Regulate the setpoint to 100% flow and adjust the inlet
and outlet pressures to calibration conditions. Verify that the output
signal reaches its full scale value and stabilizes at that value. Vary the
command voltage over the 1 to 100% range and verify that the output
signal follows the setpoint. If possible, connect a flow measurement
device to monitor the actual flow behavior and verify the accuracy of
the mass flow instrument. If the mass flow instrument performs as
described above, then it is functioning correctly and the problem may
lie elsewhere.
System Checks
The Brooks SLAMf Series Flowmeters and Controllers are generally used as
a component in gas handling systems, which can be complex in nature. It can
therefore be very difficult to isolate a malfunction in the system. An inaccurate
-
ly diagnosed malfunction can cause many hours of unnecessary downtime.
If possible, perform the following system checks before removing a suspect
Mass Flow Meter or Controller for bench troubleshooting or return to the fac-
tory, (especially if the system is new):
1. Verify a low resistance common connection and that the correct power
supply voltage and signals are present on the connector of the Smart
TMF.
2. Verify that the process gas connections have been made correctly, and
that they have been tested for leaks.
3. If the Mass Flow Controller appears to be functioning but cannot
achieve setpoint, verify that there is sufficient inlet pressure and pres
-
sure drop at the controller to provide the required flow.
Bench Troubleshooting
1. Establish a proper connection between the Brooks SLAMf Digital Se-
ries Mass Flow Meter or Controller (using Figure 4-1 as a reference).
Switch on the power and allow the instrument to warm-up for 45 min-
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