MRP4 / MRP5 / MRP6
P. 6 / 8
EM-4824 Rev.7
ADJUSTMENT PROCEDURE
Open the cover and adjust ZERO, SPAN, DZ (deadband),
DLY (re-starting timer) potentiometers and the direct/re
-
verse SW on the control PCB as shown in Figure 3.
Other adjustments which are paint locked are for factory
use only and should be changed only by qualified M-System
personnel. M-System is not liable for any malfunction or
inconvenience caused by unauthorized change of them by
the user.
■
DIRECT/REVERSE ACTION
The actuator action is factory set to “Reverse” (the output
stem, seen from the cover, turns counterclockwise, with an
input signal increase). For changing the setting, use the
DIP SW on the control PCB. Refer to Tables 2 and 3.
Remark 1: SW1-4 is not used.
Remark 2: With the direct action, the position output is
5 – 1V DC proportional to the input 0 – 100%.
Table 2. Switching Actions
ACTION
SW1-3 EXPLANATIONS
*
1
Direct
ON
Output stem turns CW with an
input increase.
Reverse
OFF
Output stem turns CCW with an
input increase.
Table 3. Operations at Abnormally Low Input
OPERATION
*
1
SW1-1 SW1-2
Stop
*
2
ON
Clockwise
OFF
OFF
Counterclockwise
ON
OFF
*1. Seen from the cover.
*2.
Whatever setting for SW1-1 is disregarded for Stop mode.
■
GENERAL
After installing the valve and actuator, go to adjustments in
order of zero, span, and sensitivity (deadband). If optional
limit switches are provided, adjust them at the last.
The following explanation applies to reverse action For di-
rect action, read the value in the brackets [ ].
Remark: Applying an over-torque to the adjustments may
destroy stoppers or other sections of them. Use a small-
sized screwdriver and be sure to stop turning as soon as
they hit the stoppers.
■
ADJUSTMENT PROCEDURE
A) Zero and Span
• Apply power supply voltage and 0% [100%] input. Turn
ZERO adjustment until the output stem reaches an ap
-
propriate fully-clockwise position.
• Apply 100% [0%] input. Turn SPAN adjustment until the
output stem reaches an appropriate fully-counterclock-
wise position.
• With 0% [100%] input again, check that the output stem
is at the appropriate angle. If the position is shifted, go
through the above procedure again.
Remark 1: There is only minimal effect of span adjustment
to zero point, thus the stem position shifts very little at the
extended side when the span potentiometer is turned.
B) Sensitivity (Deadband)
When the motor repeats small inverting movements with
-
out stopping still for small input changes, widen the dead-
band by turning the DZ adjustment clockwise.
C) Limit Switches (optional)
Loosen the screws and adjust positions of the dogs. See Fig
-
ure 8.
This adjustment cannot be done in an intermediate position
of the valve. Set it at the fully open or closed position.
Potentiometer
Limit Switches
Dog (full-opened position)
Screws
Dog (full-closed position)
Figure 8. Limit Switches
Rugghölzli 2
CH - 5453 Busslingen
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