Blodgett MT3870, Service And Repair Manual

Page: 45 / 69

CALIBRATION AND ADJUSTMENT
4-8
OPEN LOOP SYSTEM - TWIN BELT
To enter the calibration mode:
1. Press the ON/OFF key until OFF is displayed.
2. Press CLEAR FRONT BELT, FRONT BELT,
FRONT BELT, PROG/ENTER to enter the AcĆ
cess mode. The display flashes ACCESS .
3. The display reads ACTIVE BELT-? . Press front
belt for Front Belt Calibration
4. The display reads FRONT-INIT-F .
Belt speed calibration:
1. The display reads BELT SIZE-?. Enter the
length of the conveyor belt for your model. See
TABLE 5. Press the PROG/ENTER key.
2. The display reads STEP-1. The controller is in
Step 1 of the calibration procedure: maximum
belt speed. The motor control is automatically
set to its maximum output. Place an object on
the belt and note the time from entrance to exit.
NOTE: Be certain to measure either the leadĆ
ing edge in and out or the trailing edge
in and out. Do not use the leading edge
in and the trailing edge out.
A.) The display reads STEP-1TIME-?. Enter
the time measured in STEP-1. Min: 0
Max: 59:59 (min:sec). Press the PROG/
ENTER key.
B.) The display reads STEP-1DIST-?. Enter
the belt length for your model. See
TABLE 4. Press the PROG/ENTER key.
3. The display reads STEP-2. The controller is in
Step 2 of the calibration procedure: minimum
belt speed. The motor control is automatically
set to its minimum output.
The belt will travel very slowly during this part
of the calibration procedure. To minimize the
time spent on STEP-2, measure off 10" on the
conveyor support. Place an object on the belt
and note the travel time for the 10" measured
distance.
A.) The display reads
STEP-2 TIME-?. Enter
the measured travel time for STEP-2. Min:
0 Max: 59:59 (min:sec). Press the PROG/
ENTER key.
B.) The display reads STEP-2 DIST-?. Enter
10". Press the PROG/ENTER key.
4. The display reads MIN-TM ENTRY? (the fastĆ
est belt speed). Limits of this value are deterĆ
mined by the Step-1 and Step-2 calibration
values. See TABLE 5 for correct entry for this
model. Press the PROG/ENTER key.
5. The display reads MAX-TM ENTRY? ( slowest
belt speed). Limits of this value are determined
by the Step 1 and Step 2 calibration values.
Use 1600 (16 min). Press the PROG/ENTER
key.
6. The display flashes DONE and SAVE.
Repeat the procedure for the rear belt by pressing,
CLEAR, REAR BELT, REAR BELT, REAR BELT,
PROG/ENTER .
NOTE: During these adjustments, pressing the
clear button will abort all entries and reĆ
quire reprogramming of belt time mode.
When exiting the Belt Speed Calibration
Mode, enter a time. Otherwise the time deĆ
faults to zero and the oven will not heat, and
the belt will not move.
Oven
Type
Belt Length/
Distance
Minimum
Oven Entry
Oven
Type
Belt Length/
Distance
Minimum
Oven Entry
MT1828 28 330 (3 min, 30 sec) MT3270 70 330 (3 min, 30 sec)
MT2136 36 200 (2 min) MT3855 55 330 (3 min, 30 sec)
MT3240 40 300 (3 min, 00 sec) MT3870 70 330 (3 min, 30 sec)
MT3255 55 300 (3 min, 00 sec)
TABLE 5