J.R. Merritt Controls MPFC Guide
MPFC Adjustment Instructions
The threshold setting and full output setting are factory adjusted for your specific valve coil. Additional field
adjustments are recommended to tune each machine function to the desired operation.
CW rotation increases the output.
CCW rotation decreases the output.
Some interaction may occur between adjustments of the trim pots and some re-adjustment of the trim pots may be
required to achieve the optimum setting. The trim pots are 22 turn devices and will require several turns before an
appreciable change in response is observed.
Adjustment Priority.
1. Full Output Adjust Trim pot (MAX 1): With the handle fully deflected adjust the MAX 1 trim pot CW until the
desired speed is achieved. Caution: Do not over adjust. To insure that the full speed adjustment is not
saturated, back the handle off from full travel 5-10°, a change in performance should be observed. If no change
is noticed MAX 1 is saturated (over adjusted). Turn MAX 1 CCW 5 turns and re-check for a response change
just off the end of the travel again.
2. Threshold (THRES 1): Deflect handle slowly about 5° from off to adjust where the LED turns on then adjust the
THRES 1 trim pot CW to increase the start speed of the function you are controlling. To obtain a slower speed
at this position turn the THRES 1 trim pot CCW until the desired speed is observed. Re-check maximum speed
setting and re-adjust MAX 1 again if necessary to the desired maximum speed. A correctly adjusted controller
will start the function moving when the handle is initially deflected and reach full speed just at the end of travel.
Option Adjustments
3. Dual Full Output Adjust (MAX 2): An independent adjustment of the full output in each direction can be
achieved with this option. MAX 1 adjusts the output at full handle travel in ”A” direction. MAX 2 adjusts the
output at full handle travel in “B” direction. Follow the instructions for MAX 1 adjustment above when adjusting
MAX 1 for “A” and MAX 2 for “B” direction.
4. Hi-Lo Range Adjustment (HLRA): Two high-speed settings can be achieved when the handle is fully
deflected. Full proportionality is maintained between the threshold setting and either the low range or the high
range full output setting. The selection of each range is achieved by either connecting or disconnecting the
supply voltage to terminal J5 pin 2. When the supply voltage is applied to J5-2, the circuit selects the high
range setting. When power is removed from J5-2, the circuit defaults to the low range setting.
High Range Adjustment HI (MAX 1): Apply power to J5-2 and fully deflect the handle in the ‘A’ direction.
Begin adjustment by following Adjustment Priority (1) procedures and adjust MAX 1 trim pot, which is now your
high range trim pot. Whenever source power is connected to J5-2 maximum output will be achieved for this
function.
High Range Adjustment HI (MAX 2): Apply power to J5-2 and fully deflect the handle in the ‘B’ direction.
Begin adjustment by following Adjustment Priority (1) procedures and adjust MAX 2 trim pot, which is now your
high range trim pot. Whenever source power is connected to J5-2 maximum output will be achieved for this
function.
Low Range Adjustment LO (HI/LO): When the source voltage is disconnected from J5-2 by an external
contact or other means the circuit will default to low range. With J5-2 disconnected deflect the handle fully and
adjust the HI/LO trim pot to the desired low speed output. Again begin this adjustment by following the
procedures outlined in Adjustment Priority (1) for MAX 1 trim pot. With handle fully deflected re-connect the
source power to J5-2 and then disconnect it again. A noticeable change in full output speed should be
observed.
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1-800-333-JRMC
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www.jrmerritt.com
502
Pub.
# 3
7.L
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Reference MPFC Electronics Hook up and Wiring Instructions
for trim pot designation code and description.
MPFC Adjustment Instructions
5. Ramp (RAMP 1): The ramp option compensates for jerky handle movements by providing a smooth response.
Turning the trim pot Ramp 1 CW increases the ramp time and lessens the response time to handle movement.
CCW adjustment decreases the ramp time and increases the response time to handle movement. The
standard ramp time is adjustable from 0-2.5 seconds. 0 to 1, 2, 3, 4 or 5 seconds adjustment range is available
on request. Ramping occurs between the threshold setting and the full output setting. If the handle is returned
to off the function will ramp down to the threshold level and then stop.
6. Dual Threshold Adjust (THRES 2): An independent adjustment of the threshold output in each direction can
be achieved with this option. Follow THRES 1 threshold adjustment procedure and adjust THRES 2 pot to
adjust threshold in the reverse direction.
7. Dual Ramp (RAMP 2): An independent adjustment of the ramp time in each direction can be achieved with this
option. Allows the user to independently adjust the ramp time for each direction of a particular function. Follow
Ramp adjustment procedures and adjust Ramp 2 pot to adjust the ramp in the reverse direction.
MPFC Electronics Trouble Shooting Instructions
PROBLEM PROBABLE CAUSE ITEM TO CHECK
1.1 No power to the
controller.
1.1.1 LED’s will not light
1.1.2 Check fuse
1.1.3 Check for supply voltage with VM at (+) and (–) terminals.
Fig. A
1.1.4 Check for disconnected plugs and connectors at
controller.
1.2 Defective on/off switch
on controller.
1.2.1 With VM check supply from (-) terminal to (x) terminal.
Deflect handle, voltage should be present. If not, replace
contact. Fig. B
1.3 Controller output shorted
to ground. LED’s will not
light.
1.3.1 Locate shorted coil or wire and replace or repair wire.
1.3.2 Replace fuse if applicable.
1.3.3 If voltage is present at the (x) terminal and LED’s fail to
light replace the circuit board.
1.3.4 Note: If you have more than one identical electronic
amplifier in the system, re-connect one in place of the
other to confirm your diagnosis at this time.
1.4 Open circuit between
controller and coil.
1.4.1 ‘A’ or ‘B’ LED will light, but no change in brilliancy is
noticed when handle is deflected in both directions.
1.4.2 Re-connecting of an adjacent identical controller to this
function, if available.
1.4.3 If function is still inoperative, look for the broken wire,
open coil or loose connection at valve or controller.
1. Function
inoperative when
controller is
operated.
1.5 Trim pots out of
adjustment.
1.5.1 Refer to MPFC Adjustment Instructions.
1.5.2 Turn all trim pots CCW 10-15 turns. You should hear a
click. Then follow MPFC Adjustment Instructions.
2. Function Jerks on
turn on.
2.1 Threshold trim pot
adjustment too high.
2.1.1 Turn threshold trim pot CCW several turns. Refer to
MPFC Adjustment Instructions.
S
trat
f
ord, CT
•
••
•
1-800-333-JRMC
•
••
•
www.jrmerritt.com
502
Pub.
# 3
7.L7
MPFC Electronics Trouble Shooting Instructions
PROBLEM PROBABLE CAUSE ITEM TO CHECK
3. Function speed
shows small
proportional change
over handle range.
3.1 Trim pots out of
adjustment.
3.1.1 Full output trim pots (MAX or HI/LO) possibly saturated
(set too high). Fully deflect handle and then back off 10
degrees. Change in function output should be noted. If
not, turn trim pot CCW several turns and observe.
Refer to MPFC Adjustment Instructions.
4. High-Low range
option will not
transfer between
Low and High
settings.
4.1 No power at terminal J5
pin 2
4.1.1 Check for source voltage at terminal J5-2 in the high
range mode. Check that the voltage is no longer
present when in low range mode. If no voltage is
present check wiring and integrity of switching device
responsible for controlling this function.
4.1.2 Check if HI/LO and MAX trim pots are adjusted
properly. See MPFC Adjustment Instructions for HLRA.
5. Ramp ineffective or
function response is
too slow.
5.1 Trim pot out of
adjustment.
5.1.1 Turn Ramp trim pot CW to slow down the output rate of
change (increases ramp time and reduces the functions
response time to handle movement).
5.1.2 Turn Ramp trim pot CCW to speed up the output rate of
change (reduces ramp time and increases the functions
response time to handle movement).
6.1 D11 Blinks 6.1.1 D11 Blinks for eight seconds during power-up. The
board runs a self-diagnostic routine. Output is
inoperative during this time
6.2 D12 Blinks 6.2.1 D12 blinks during normal operation. Board should work
properly.
6.3 D14 Blinks once 6.3.1 Command pot was not centered at startup. Center
controller handle and restart power.
6.4 D14 Blinks twice 6.4.1 Broken pot wire. Turn power off and check all wiring for
open connections.
6.5 D14 Blinks 3 times 6.5.1 Forward threshold greater than high range. Increase
MAX. 1 adjustment or reduce Thres.1 pot adjustment
6.6 D14 Blinks 4 times 6.6.1 Reverse threshold greater than high range. Increase
MAX. 2 pot adjustment or reduce Thres.2 pot
adjustment
6.7 D14 Blinks 5 times 6.7.1 Forward threshold greater than low range. Increase
HI/LO pot adjustment or reduce Thres.1 pot adjustment
6. Diagnostic LED’s
lighting
6.8 D14 Blinks 6 times 6.8.1 Reverse threshold greater than low range. Increase
HI/LO pot adjustment or reduce Thres.2 pot adjustment
S
trat
f
ord, CT
•
••
•
1-800-333-JRMC
•
••
•
www.jrmerritt.com
502
Pub.
# 3
7.L
8
