Data Sheet for Product

Technical Instructions MVS661..N Series Modulating Refrigerant Valves
Document Number 155-404 for Ammonia (R717) and Safety Refrigerants
May 11, 2016
Page 4 Siemens Industry, Inc.
DIP Switch
Configurations
Table 3. DIP Switch Configurations.
Switch
Function
ON/OFF
Description
Positioning signal Y
ON
Current (mA)
OFF
Voltage (V)
1)
Positioning range Y and U
ON
2 to 10 Vdc, 4 to 20 mA
OFF
0 to 10 Vdc, 0 to 20 mA
1)
Position feedback U
ON
Current (mA)
OFF
Voltage (V)
1)
Nominal flow rate C
V
(k
vs
)
ON
63%
OFF
100%
1)
1)
Factory setting
C
V
(K
VS
) reduction
For C
V
(k
vs
) reduction (DIP switch 4 in
position ON), the stroke is limited to 63%
mechanical stroke. 63% of full stroke then
corresponds to an input/output signal of
10V.
If, in addition, the stroke is limited to
80%, for example, the minimum stroke is
0.63 × 0.8 = 0.50 of full stroke.
Minimum stroke setting
With a suction throttle valve, it is essential
that a minimum stroke limit be maintained
to ensure compressor cooling and
efficient oil return. This can be achieved
with a re-injection valve, a bypass line
across the valve, or a guaranteed
minimum opening of the valve. The
minimum stroke can be defined using the
controller and control signal Y, or it can
be set directly with potentiometer Rv.
The factory setting is zero (mechanical stop in counterclockwise direction, CCW). The
minimum stroke can be set by turning the potentiometer clockwise (CW) to a maximum
of 80% C
V
(k
vs
).
CAUTION:
Do not use potentiometer Rv to limit the stroke on expansion applications.
The valve must be able to fully close.