Pg 3.15
7) After the cut is completed HDN input should light, HDN output should go out, the HUP
output should light and the head should mo
ve up. When the head reaches it's up limit, HUP input
should come on, RHD output off and the cycle repeats with the next length being clamped on by
the shuttle, front vise opening and the length being brought forward to home position.
As mentioned, beside each input and output terminal there is a bank of red LEDs. Each light
corresponds to its input or output. An input LED will light when it's specific input signal is being received
at the PLC and output LED's will light when the PLC commands specific outputs. If an output LED is on
but the output does not happen, check for voltage at the specific output wire. If voltage is not present
then either the output relay is faulty/stuck or the output (3 amp) fuse has blown. (See fuse information
below) If a fuse is blown, a shorted directional valve coil (good coil should measure 30 to 40 ohms),
shorted noise suppresser at the coil, or shorted wiring could be the cause. If the fuse is good and no
output voltage condition still exists, with the output light on, then the relay is defective. If this is the case
the PLC will have to be returned to the manufacturer for repair. (Contact HYD-MECH SAWS).
FUSES: The PLC has five glass fuses in line with it.
Fuse 'F1' is a 2 amp instant blow fuse which feeds power to the input side of the PLC
through input terminal 'L'.
Fuses 'F2' to 'F5' 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:
F2 is wired to terminal 'COM 1' supplying Outputs - Y0, Y1, Y2, Y3
F3 to terminal 'COM 2' supplying Outputs - Y4, Y5, Y6, Y7
F4 to terminal 'COM 3' supplying Outputs - Y10, Y11, Y12, Y14
F5 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 page 3.17 - Status lights) - 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.
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