FP-RLY-420 4 www.natinst.com
Figures2a and 2b show examples of basic wiring connections.
Figure 2. Basic Field Connection (Two Channels Shown)
Relay Output Circuit
The outputs of the FP-RLY-420 consist of Form A
electromechanical relays. The power-up state is off (open) to
ensure safe installation. In the ON state, the N.O. and I.C. contacts
connect together to form a short circuit. Choose the impedance of
the loads so that the current switched by any one channel in the ON
state is no more than 3A.
In the ON state, there is an effective resistance of 100 mΩ between
the N.O. and I.C. terminals, which causes a voltage drop. For
example, if the current is 3 A, the voltage drop across the N.O.
andI.C. terminals is 0.3 V.
VC Vsup
–
+
N.O.
N.O.
I.C.
a. Total Current Less
Than 6 Amps
I.C.
COM
Vsup
N.O.
I.C.
COM Load
b. Total Current Greater
Than 6 Amps
Load
–
+
Load
N.O.
I.C. –
+
Load