Modbus rtu serial communications, Relay connections, Relay4 relay3 – Precision Digital PD6300 User Manual
Page 24: Relay2 relay1, Figure 11: relay connections
Model PD6300 Pulse Input Rate/Totalizer
Instruction Manual
24
Modbus RTU Serial Communications
Serial communications connection is made to an RJ45 connector labeled
M-LINK on Figure 6. Use the PDA1232 for RS-232 interfacing or the
PDA1485 for RS-422/485 interfacing. The same port is used for interfac-
ing 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 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 11: Relay Connections