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Calibrating the DMA
Note:
The red and yellow switches are factory set outside of
the 0 to 90˚ operating range. Do not change these adjust-
ment dials until calibration is complete.
DO NOT
use these
switches in lieu of the calibration.
To Adjust Minimum Position
1. Apply a 4 mA DC input signal.
2. Turn the
Y min
(Zero) potentiometer (adjusting
range 0 to 100 % of stroke) to position the actua-
tor at the desired minimum position. Turning
Y min
(Zero) CCW drives the minimum position towards
0˚.
To Adjust Maximum Position
1. Apply 20 mA DC input signal.
2. Turn the
Y max
(Span) potentiometer (adjusting
range 25 to 100 % of stroke) to position the actua-
tor at the desired maximum position. Turning
Y max
(Span) CCW drives the setpoint towards 0˚.
Note:
Y min
(
Zero) must be no more than 75 % of
Y max
(Span) (reference: 90˚ = 100%). E.g. if the maximum position
is set at 85˚, the minimum position can be set at 64˚ maxi-
mum. (85˚ * 0.75 = 64˚).
Switch Adjustment
:
Note: Use the scale under the Red ST1 switch to field set
the switches.The DMA incorperates two limit switches that
limit the crank shaft from exceeding a set point if the zero
or span potentiometer fails. The DMA also has an
SPDT auxilary switch. All switches can be adjusted
anywhere over the 90˚stroke.
ST1 Limit Switch (Red)
:
This switch limits the mini-
mum position at 0˚ or more. Set the switch at approx.
1˚ LESS than the Y Min. setpoint. The small set
screw on the side of the red dial can be used for fine
tuning adjustment.
ST2 Limit Switch (Yellow)
:
This switch limits the maxi-
mum position at 90˚ or less. Set the switch at ap-
prox. 1˚ MORE than the Y Max. setpoint. The small
set screw on the side of the yellow dial can be used
for fine tuning adjustment.
MV Auxiliary-Switch (Yellow):
Set the switch to trip at
the desired setpoint using the scale under the Red
ST1 switch. When the motor is at 0˚, the NC contact 4
and 3 opens, and the NO contact 4 and 2 closes.
DMA ACTUATOR CALIBRATION AND ADJUSTMENTS
ACCESSORIES
Description
NEMA 4 metal enclosure
Order No.
240-456