Johnson Controls RA-3 Series Service And Data Information page 24

6 E
Function
Valve actuator without positioner
Terminal connection 1 + 2:
Terminal connection 1 + 3:
Valve actuator with positioner
With 0V (0 mA) on terminal E:
Direct action (DA):
Reverse action (RA):
Note:
Parallel operation of several valve actuators without built-in positioner is only possible using isolation relays!
Electronic positioner EPOS
Actuators for 0...10 V (20 mA) control are fitted with an electronic positioner EPOS. The EPOS is a company
made pcb.
Span, start point and action are adjustable.
Curve 1 Direct action (DW) Start point 0.5 V (1 mA) Span 9 V (18 mA)
Curve 2 Reverse action (UW) Start point 9.5 V (19 mA) Span 9 V (18 mA)
Curve 3 Reverse action (RA) Start point 4 V (8 mA) Span 3.5 V (7 mA)
Curve 4 Direct action (DA) Start point 5 V (10 mA) Span 4.5 V (9 mA)
0 %
50 %
[Stroke]
100 %
0
0
Models with auxiliary switches
The auxiliary switches S3 and S4 (B) or operated by cam disk. The cam disks can be set for any stroke
position using a special tool provided.
Models with position feedback
The feedback potentiometer (C) serves to indicate the position and can be adjusted on the shaft / friction
clutch with a screwdriver.
Not valid for models with positioner
If the actuator stem has been driven to the extended end position (terminals 1 and 2), then the nominal
resistance of the potentiometer can be measured between terminals 10 and 12.
Actuator stem is extended.
Actuator stem is retracted.
Actuator stem is extended.
Actuator stem is retracted.
2
3
1 2 3 4
2 4 6 8
Voltage/current on terminal E
"Y" output:
0 Volt (0 mA)
10 Volt (20 mA)
1
4
5 6 7 8
10 12 14 16
111 6041 050 E
9 10 V DC
18 20 mA