Relay connections, Relay4 relay3, Relay2 relay1 – Precision Digital PD6310 User Manual
Page 27: Switching inductive loads, Figure 14: relay connections, Use capacitors rated for 250 vac
Model PD6210 & PD6310 Batch Controllers
Instruction Manual
27
The same port is used for interfacing with all expansion modules (e.g.
external relays, digital I/O).
Use the PDA1200 controller copy cable for meter-to-meter interfacing for
cloning purposes (i.e. copying settings from one controller to other con-
trollers).
Relay Connections
Relay connections are made to two six-terminal connectors labeled
RELAY1 – RELAY4 on Figure 6. Each relay’s C terminal is common only
to the normally open (NO) and normally closed (NC) contacts of the cor-
responding relay. The relays’ C terminals should not be confused with
the COM (common) terminal of the INPUT SIGNAL connector.
C
NO
NO
NC
NC
C
RELAY4
RELAY3
4
3
6
5
2
1
C
NO
NO
NC
NC
C
RELAY2
RELAY1
4
3
6
5
2
1
Figure 14: Relay Connections
Switching Inductive Loads
The use of suppressors (snubbers) is strongly recommended when
switching inductive loads to prevent disrupting the microprocessor’s op-
eration. The suppressors also prolong the life of the relay contacts. Sup-
pression can be obtained with resistor-capacitor (RC) networks assem-
bled by the user or purchased as complete assemblies. Refer to the fol-
lowing circuits for RC network assembly and installation:
C
R
C
R
Figure 15: AC and DC Loads Protection
Choose R and C as follows:
R: 0.5 to 1
for each volt across the contacts
C: 0.5 to 1 µF for each amp through closed contacts
Notes:
1. Use capacitors rated for 250 VAC.