J.R. Merritt Controls MPFC, Adjustment Instructions, Page: 2 / 4

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.
Stratford, CT
••••
1-800-333-JRMC
••••
www.jrmerritt.com
502
Pub. # 37.L7