Brooks Instrument 5861E - Manual (Page 23)

4-3
Model 5861E
Section 4 Maintenance Installation and Operation Manual
X-TMF-5861E-MFM-eng
Part Number: 541B107AAG
November, 2008
A. System Checks
The Model 5861E is generally used as a component in gas handling
systems which can be quite complex. This can make the task of isolating a
malfunction in the system a difficult one. An incorrectly diagnosed
malfunction can cause many hours of unnecessary downtime. If possible,
make the following system checks before removing a suspected defective
mass flow controller for bench troubleshooting or return, especially if the
system is new:
1. Verify a low resistance common connection and that the correct power
supply voltage and signals are reaching and leaving the meter. The
Break-out Board (refer to Table 5-2) listed in section 5 , will make this
job much easier.
2. Verify that the process gas connections have been correctly terminated
and leak checked.
N
Bench Troubleshooting
1. Properly connect the mass flow controller to a ±15 Vdc power supply,
and connect an output signal readout device (4-1/2 digit voltmeter
recommended) to (Pins 2 and 10 D-connector) (Refer to Figure 2-2).
Apply power, and allow the flowmeter to warm up for 45 minutes. Do
not connect to a gas source at this time. Observe the output signal
and, if necessary perform the zero adjustment procedure (Section 3-3).
If the output signal will not zero properly, refer to the sensor
troubleshooting section and check the sensor. If the sensor is
electrically functional, the printed circuit board is defective and will
require replacement.
2. Connect the flowmeter to a source of the gas on which it was originally
calibrated. Increase the flow until 100% indication (5.00Vdc) is
achieved. Vary the flow rate over the 2 to 100% range and verify that
the output signal follows the flow rate. If possible, connect a flow
measurement device in series with the mass flowmeter to observe the
actual flow behavior and verify the accurcy of the mass flometer. If the
mass flowmeter functions as described above, it is functioning properly
and the problem may lie elsewhere.
Table 4-1 lists possible malfunctions which may be encountered during
bench troubleshooting.
Sensor Troubleshooting
If it is believed the sensor coils are either open or shorted, troubleshoot
using Table 4-2. If any of the steps do not produce the expected results the