Brooks Instrument 5850EM - Manual (Page 53)

4-3
Brooks ® Models 5964, 5850EM
Section 4 Maintenance Installation and Operation Manual
X-TMF-5964-5850EM-MFC-eng
Part Number: 541B121AHG
November, 2008
B. Bench Troubleshooting
In order to assist in troubleshooting it is highly recommended that the
controller be installed in a flow circuit as shown in Figure 3-13.
1. Properly connect the mass flow controller to a ±15 Vdc power supply or
a +15 to +28 Vdc in the case of a current I/O board. Connect a com-
mand voltage source and an output signal readout device (4-1/2 digit
voltmeter recommended) to Pins 2 and 3 on the Card Edge version, or
Pins 2 and 10 for the D-Connector version (Refer to Figure 2-2, 2-3, 2-4
or 2-6). Apply power, set the command voltage to zero and allow the
controller 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 adjust-
ment procedure (Section 3-6). 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 controller to a source of the gas on which it was originally
calibrated. Command 100% flow and adjust the inlet and outlet pres-
sures to the calibration conditions. Verify that the output signal reaches
and stabilizes at 5.000 Volts. Vary the command voltage over the
control range and verify that the output signal follows the command
input.
Apply +15 Volts to the valve override input, (Pin 9 for the Card Edge
version, Pin 12 for D-Connector version) and verify that the output
exceeds 5.000 Volts.
Apply -15 Volts to the valve override terminal and verify that the output
signal falls below 0.100 Volts for an elastomeric valve seat and below
400 Volts for a metal valve seat. If the controller is connected in series
with a suitable flow standard, observe the actual flow behavior and
verify the accuracy of the mass flow controller. If the mass flow control-
ler functions as described above, it is functioning properly and the
problem is most likely elsewhere. Table 4-1 lists possible malfunctions
which may be encountered during bench troubleshooting.
C. 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 expected results, the
sensor assembly is defective. Return to Brooks Instrument for sensor
replacement.
Note:Do not attempt to disassemble the sensor.
D. Cleaning Procedures
No routine external cleaning is required for Brooks thermal mass flow
controller. Should the Models 5964 or 5850EM Mass Flow Controller
require cleaning due to deposition, return the device to
Brooks Instrument for servicing by trained technicians.