2
2 To 10 Vdc Or 0 To 10 Vdc Stand Alone Thermostat
( Power To The Thermostat Is Supplied By The R851V )
0 To 135
Ω
Stand Alone Thermostat
2 To 10 Vdc Or 0 To 10 Vdc From D.D.C.
Building Automation System
4 To 20 mA From D.D.C.
Building Automation System
24 VAC POWER & RELAY OUTPUT WIRING
The wiring diagrams are for the R851V-8 models with 8 outputs. The wiring for the R851V-4 is the same except that the unit only
has 4 outputs.
Terminals
Screw terminal & connector #1
Common
Screw terminal & connector #2
24 Vac
Screw terminal & connector #3
Control Signal input
•
It is not necessary to ground any leg of the transformer to earth with the controller card.
•
The controller uses internally a half wave rectifier bridge. On 0 to 10 Vdc control signal, the reference of the control signal is the
Common of the power supply of the SCR controller card.
•
Use a Class 1 ( properly fused ) or Class 2, CSA or UL recognized transformer.
4 STAGE APPLICATION
R851V-4
R851V-4 Control Switch
Number of
stage
Switch #3
Switch #4
1
Off
Off
2
On
Off
3
Off
On
4
On
On
Common
24 Vac
0 to 10 Vdc
output
2 Vdc = 0% capacity
10 Vdc = 100% capacity
1
2
3
1
1
2
3
ON
4
I N P U T
R
W
B
0 Ohms = 0% capacity
135 Ohms = 100% capacity
1
2
3
1
1
2
3
ON
4
I N P U T
-
+
2 Vdc = 0% capacity
10 Vdc = 100% capacity
1
2
3
1
1
2
3
ON
4
I N P U T
4 mA = 0% capacity
20 mA = 100% capacity
-
+
1
2
3
1
1
2
3
ON
4
I N P U T
1
2
3
1
2
3
ON
4
O N T R O L
1
2
3
ON
4
I N P U T C
200
