Modbus rtu serial communications, Relay connections, Relay4 relay3 – Precision Digital PD6400 User Manual
Page 23: Relay2 relay1
Model PD6400 High Voltage & Current Meter
Instruction Manual
23
Modbus RTU Serial Communications
Serial communications connection is made to an RJ45 connector
labeled M-LINK on Figure 6. For interfacing to the P
RO
V
U
®
, use the
PDA1232 for RS-232, the PDA1485 for RS-485, or the PDA8008 for
USB. The same port is used for interfacing with all expansion modules
(e.g. external relays, digital I/O).
Use the PDA1200 meter copy cable for meter-to-meter interfacing for
cloning purposes (i.e. copying settings from one meter to other meters).
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
corresponding relay. The relays’ C terminals should not be confused
with the COM (common) terminal of the INPUT SIGNAL connector.
Figure 16. Relay Connections
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