Technical_reference - 第62页
Technical Service Manual 62 Revision Dat e: August 2004 PROBLEM W ITH T HE SIGNA L FROM T HE CONTROLLER T O I/O BOARD The c onvey or will not run because ther e is a problem with the signal from the c ontroller to the I/…
Technical Service Manual 61 Revision Date: August 2004
UNRELIABLE OUTPUT FROM DC DRIVE MODULE
The DC drive module may be causing one of the following:
1) (No Output) The conveyor will not run
2) (No Output) The conveyor stops running
3) (Intermittent Output) The conveyor speed is unstable
4) (Intermittent Output) The conveyor “jerks” (motion is not smooth)
POSSIBLE CAUSES
The DC drive module is an electronic assembly that receives a control signal from the controller on pins +SIG and -SIG
and AC voltage on L1 and L2. This produces DC voltage on pins A1 and A2 at a level sufficient to power the Conveyor
motor at various speeds.
HINT: Check the following items when troubleshooting a faulty DC drive circuit.
The most likely are listed first:
1) DC drive module.
2) Conveyor motor.
3) I/O relay.
4) E-STOP switches.
5) K37 & K38.
6) F50, F52 or F55 (This will cause complete system failure).
7) Controller.
8) Speed – (If the conveyor is set less than 8”/min, the conveyor will become unstable
(DC motor, NOT stepper motor)
In addition to the items listed above, check the signals from the oven controller to help determine why there is no signal
from the DC DRIVE MODULE. The signals in question are listed on the Control ladder print as follows:
Analog Out Common (A1 Board PX9-18) (-SIG drive V1)
Analog Out 1 (A1 Board PX9-17) (+SIG drive V1)
(A voltage level between 0v and +10v should be found when checking these two signals with a voltmeter. Place
the negative lead on Analog Out Common and the positive lead on Analog Out 1)
Check the switches, circuit breakers and relays, to be securely mounted and that the wires are connected correctly* and
tightly.
When checking the drive motor, refer to the section on motor troubleshooting if the fault is not obvious.
The final test will be to replace the DC Drive Module after all other possibilities have been eliminated.
* Use the oven schematics to verify correctly connected wires.
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Technical Service Manual 62 Revision Date: August 2004
PROBLEM WITH THE SIGNAL FROM THE CONTROLLER TO I/O BOARD
The conveyor will not run because there is a problem with the signal from the controller to the I/O board.
POSSIBLE CAUSES
Check the following in the order given for the source of the problem.
1 Check the Alarm Conditions displayed on the computer screen.
2 I/O relay board (Check for the led lit on A1-K12).
3 Connections from the controller to the I/O relay board A1
4 Controller board.
5 Encoder (check the signal levels)
NO SIGNAL TO DC DRIVE MODULE FROM THE I/O BOARD
The conveyor will not run because there is no signal from the I/O Board to the DC drive module.
POSSIBLE CAUSES
Check the following for a solution: the most likely is listed first;
1 An alarm condition.
2 The connections or cables from the I/O Board to the DC drive module.
3 The controller.
4 The software in the computer or controller.
See the Control ladder print for the circuit details.
THE CONVEYOR IS JAMMED
The conveyor is jammed. This is causing the conveyor either to not run or to stop running.
POSSIBLE CAUSES
If the conveyor is jammed, there is a mechanical reason for it. The most common reasons for conveyor jams are:
1 Lubrication problems on a chain or combo conveyor. If the chain is not lubricated at the appropriate
intervals, the conveyor may jam and stop.
2 Mechanical jam in the tunnel.
3 Misalignment of the sprockets or idlers.)
4 Conveyor clutch
5 Conveyor motor.
6 Excess belt or chain catching and hanging up on something under the oven.
* See the Preventive Maintenance Manual for recommended lubrication intervals.
CONVEYOR MOTOR DOES NOT OPERATE
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Technical Service Manual 63 Revision Date: August 2004
The conveyor motor has illustrated one of the following symptoms.
1) The conveyor will not run
2) The conveyor stops running
3) The conveyor speed is unstable
POSSIBLE CAUSES
Since the conveyor subsystem is an Electro-mechanical system, check the mechanical components before replacing
electrical parts. Ensure that the belt is not hung up below the oven, or that a board is not jammed somewhere on the
conveyor. After confirming that the mechanical elements of the conveyor are in operating order, start troubleshooting the
electrical components
The most likely are listed first:
1) Conveyor motor.
2) DC drive module.
3) I/O Interface board.
4) E-STOP switches.
5) Electrical enclosure interlock switches.
6) K37, K38.
7) F50, F52, F55 (When tripped, causes complete power loss to oven).
8) Controller signal).
9) Controller.).
CONVEYOR DRIVE CLUTCH NEEDS ADJUSTMENT
The conveyor drive clutch needs adjustment and this is causing one of the following symptoms.
1) The conveyor will not run
2) The conveyor stops running
3) The conveyor speed is unstable
4) The conveyor “jerks” (motion is not smooth)
POSSIBLE CAUSES
The conveyor clutch is mechanically connected to the end of the conveyor motor shaft and serves as protection for the
motor if there is a jam that actually stops the conveyor belt/chains from moving.
Exercise extreme caution when working near the conveyor drive system.
The clutch is set at the factory to slip at 35 + 5 foot pounds as measured with a linear scale. With time, the torque setting
may change. The adjustment mechanism is a large nut that presses against the clutch disc to create tension. To
increase the tension, turn the nut clockwise, the opposite will decrease tension. Use a linear scale and a hook on a chain
pin or a conveyor belt loop to pull until the conveyor stops moving. Read the measurement on the scale. The scale should
indicate 35 + 5 foot-pounds. If the tension cannot be adjusted between 30-40 foot pounds, the clutch may need to be
replaced. Other possible causes for improper clutch operation are:
1) Mechanical or lubrication problems with conveyor shafts.
2) Conveyor belt or chains catching and/or dragging
3) Conveyor sprockets slipping
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