Manual
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-DIN,
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8
-DIN &
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- DIN Controllers & Indicators - Product Manual
9 P6170, P8170 & P4170 VMD Controller – Model Group
These controllers are designed to control motorised valves using a three point stepping
Valve Motor Drive (VMD) control algorithm. The P6170
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16
–DIN VMD Controller (48 x
48mm), P8170
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–DIN VMD Controller (96 x 48mm) and P4170
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–DIN VMD Controller (96
x 96mm) offer similar functionality in three DIN sizes.
Open loop valve control Two process alarms
Valve position indication option Loop alarm
Auto/Manual Tuning RS485 Modbus communications option
Remote setpoint option PC configuration option
Special Wiring Considerations for Valve Motor Control
Valve Motor Drive (VMD) Controllers require two identical outputs to be assigned to position
the valve. One to Open and one to Close the valve. These outputs can be two relays, two
triacs, two SSR drivers or one dual relay. The relay contacts are rated at 240VAC (120V max
for direct Valve Motor control – see CAUTION below).
When using two relays (with SPDT change-over contacts), it is recommended to interlock the
relay wiring as shown. This prevents both motor windings from being driven at the same
time, even under fault conditions.
Open Valve Winding
Close Valve Winding
Valve Common
OPEN” RELAY
C
N/C
N/C
C
N/O
“CLOSE” RELAY
N/C
C
N/O
120VAC SUPPLY
2 x 120V = 240V
120V
N/O
“
Figure 38. Interlocking of Valve Relays
CAUTION:
The windings of a valve motor effectively form an Autotransformer. This causes a
voltage doubling effect when power is applied to either the Open or Close terminal,
causing twice the supplied voltage at the other terminal. For this reason, switching
devices directly connected to the valve motor, must only be used up to half of their
rated voltage. The maximum motor voltage when using the internal relays/triacs is
therefore 120V unless interposing relays are used. Interposing relays or other
devices used to control the valve must themselves be rated for twice the motor
supply voltage.
59305, Issue 6 – March 2006 P6170, P8170 & P4170 Model Group Page 63