Pg 45 S22A / S23A mits 2001
FUSES
The PLC has five glass fuses in line with it.
Fuse '4FU' is a 2 amp instant blow fuse which feeds power to the input side of the
PLC
through input terminal 'L'.
Fuses '5FU1' to '5FU4' are 3 amp time delay fuses which each supply power to a specific bank of output relays
through that bank of relay's 'COM' terminal:
5FU1 is wired to terminal 'COM 1' supplying Outputs - Y0, Y1, Y2, Y3
5FU2 to terminal 'COM 2' supplying Outputs - Y4, Y5, Y6, Y7
5FU3 to terminal 'COM 3' supplying Outputs - Y10, Y11, Y12, Y13
5FU4 to terminal 'COM 4' supplying Outputs - Y14, Y15, Y16, Y17
PROBLEM # 4
No Display
POSSIBLE CAUSES;
i) No power to the PLC.
ii) PLC unit failure.
iii) Faulty connection of cable between PLC & Interface
DIAGNOSIS;
i) Check POWER LED (see next page - Inputs & Outputs) - to be on when the PLC is switched on.
If the light is on, PLC may have failed. Check for proper connection of cable at PLC & at interface. If
connection is secure replace. If light is not on - check the (2 amp) PLC fuse.
If the fuse is OK, check power to it.
PROBLEM # 5
No Blade Speed Display.
POSSIBLE CAUSES;
i) Fault at proximity sensor - bad sensor, misadjusted sensor (gap should be approx. 0.015")
- contamination on the end of the sensor
ii) Fault at the PLC - bad connection of sensor wiring
- faulty PLC input
DIAGNOSIS;
i) Check for LED light on the sensor - light on indicates prox. sensor power connections are correct and
sensor is activated. Problem could be with the sensor, signal wire to the PLC or with the PLC. With blade
running, proximity LED should pulse. Likewise, the PLC input LED (X2) should be pulsing. If both LED's are
pulsing with the blade running, the PLC is the problem. If the sensor LED is pulsing but the input (X2) LED is
not; there is a problem between the sensor and the PLC input (X2) terminal.
- If the LED on the sensor is not on, the problem is with the sensor wiring or the sensor is at fault.
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