Brooks Instrument 5850EM - Manual (Page 54)

4-4
Brooks ® Models 5964, 5850EM
Section 4 Maintenance Installation and Operation Manual
X-TMF-5964-5850EM-MFC-eng
Part Number: 541B121AHG
November, 2008
Table 4-1 Bench Troubleshooting
Trouble Possible Cause Check/Corrective Action
Actual flow overshoots setpoint by Anticipate potentiometer out of adjustment. Adjust anticipate potentiometer. Refer to Sections 3-5 & 3-8 .
more than 5% full scale.
Output stays at zero level regardless Clogged Sensor tube and restrictor and/or a Clean sensor. Refer to cleaning procedure, Section 4-2D.
of command and there is no flow clogged orifice.
through the controller.
Closed or clogged flow path up- or downstream or Open valve(s). Clean filter(s). Remove any foreign material from gas delivery system.
the controller.
Clogged Control Valve. Check TP3 with the command at 100%. If the voltage is more negative than -11V,
disassemble and repair the control valve. Refer to Sections 4-3 and 4-4.
Internal reference being used as the command Refer to Section 3-4.
source and the yellow jumper is in the wrong
position.
-15 volts applied to the valve override input Check valve override input. Refer to Section 2-6 for terminal assignments.
Defective printed circuit board. Replace printed circuit board. Refer to Section 4-3.
Valve voltage not returned, Pin L at common. Check jumper for external valve return. Refer to Section 3-4.
"Valve-off" pin grounded. Check "Valve-Off" input. Refer to Section 2-6 for terminal assignments.
Output signal stays at +6.8 Volts Valve stuck open or leaky. Clean and/or adjust control valve. Refer to cleaning procedure and/or Section 4-2D.
(26 mA for Current I/O Vers.) regard-
less of command and there is flow
+15 Volts applied to the valve override input. Check the valve override terminal. Refer to Section 2-6 for terminal assignments.
through the controller.
Defective printed circuit board. Replace printed circuit board. Refer to Section 4-3.
Command input floating. Connect command signal. Refer to Section 2-6 for terminal assignments.
Pin D connected to common. Remove Pin D from common.
Output signal follows set-point at Leaky control valve Disassemble and repair valve. Refer to Section 4-3.
higher commands but will not go to
zero.
Excessive resistance in valve voltage return line. Reduce wiring resistance or reconfigure controller for "External Valve Return." Refer
to Section 3-4.
Output signal follows set-point at Insufficient inlet pressure or pressure drop. Adjust pressures, inspect in-line filters and clear/replace as necessary.
lower commands but does not reach
full scale.
Partially clogged sensor Check calibration. Refer to Section 3-7.
Partially clogged valve. Disassemble and repair control valve. Refer to Section 4-3.
Valve out of adjustment. Adjust valve. Refer to Section 4-4.
Valve guide spring failure. Check valve spring.
Controller grossly out of calibration. Partially clogged sensor. Clean sensor. Refer to the cleaning procedure, Section 4-2D.
Flow is higher than desired.
Controller grossly out of calibration. Partially clogged restrictor. Replace restrictor. Refer to Section 4-3.
Flow is lower than desired.
Controller oscillates. Pressure drop or inlet pressure excessive. Adjust pressures.
Oversized orifice. Check orifice size. Refer to Section 4-6.
Valve out of adjustment. Adjust valve. Refer to Section 4-4.
Anticipate potentiometer out of adjustment. Adjust anticipate potentiometer. Refer to Section 3-8.
Faulty pressure regulator. Check regulator output.
Defective printed circuit board. Replace printed circuit board. Refer to Section 4-3.