Electronics FC - Manual (Page 7)

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12. TROUBLE-SHOOTING GUIDE
1. SYMPTOM: Unstable operation.
If display indicates flow rate variations of more than 5%, check for the following:
a) Air leaks - nozzle, hose, valve, etc.
b) Pressure regulator malfunction (may be pulsing).
c) Contaminated shot (dust, oil, water, and broken shot).
d) Blast hose restricted during nozzle movement.
To determine if instability is caused by the shot peening machine or by the controller, put the
servo switch (2-11) down in the off position. Turn on the machine and slowly increase the set-
point until the display reads the desired flow rate. Since the servo mode is off, the controller is
acting like a power supply to the MagnaValve with no flow rate feedback information. If the flow
rate is unstable, the cause originates in the machine. If the flow rate is stable with the servo off,
then the servo needs to be readjusted. Refer to Section VI Stability Adjustments.
2. SYMPTOM: Display reads high value and does not change.
a) Wiring defect in the cable to the MagnaValve pre-amps. Check voltages at Terminals #17
and #18 for proper connection to MagnaValve.
b) Be sure MagnaValve is installed right side up (see flow arrow).
c) Check to see if the lower portion of the MagnaValve is full of shot due to hose blockage etc.
3. SYMPTOM: Set point (front panel SETKNOB) does not control flow rate.
a) Green LED (1 - 7) "Local" should be on for local set point knob operation.
b) “Enable” signal must be present (Terminal #3). Also, the "Enable" LED must be
lighted
(1-2).
c) MagnaValves operate using a magnetic field and have no moving parts. High differential air
pressure in air peening applications or suction in wheel peening applications, may force shot
through the valve. This symptom is characterized by having shot flowing when valve is off
(red valve LED=off). For direct pressure air-peening systems, be sure air pressure in the
pressure pot is equal to boost air supply. This will eliminate the differential air pressure that
can force shot through the MagnaValve.
d) MagnaValve valve driver module may be defective. The output current setting is listed on the
valve driver module. Check the valve current with an ammeter in series with the wire lead
from the controller to the valve driver module. Contact factory for assistance.
4. SYMPTOM: No alarm relay contact output.
a) “Enable” must be on (1 - 2).
b) “Servo” switch must be on (up) (2 - 11).
c) “High” (1-5) or low (1-6) Alarm LED must be on (bright) for alarm relay contact to transfer.
d) Check ± alarm bandwidth; it may be too large.
e) Check wiring from the terminals:
f) “High” Alarm Relay Contact
g) “Common” Alarm Relay Contact
h) “Low” Alarm Relay Contact
i) “Alarm Reset” signal, (115VAC) should be absent from terminal #14.