Hach SC1500 User Manual page 17

Terminal Description
1 Relay 1, NC
2 Relay 1, common
3 Relay 1, NO
4 Relay 2, NC
5 Relay 2, common
6 Relay 2, NO
NC = normally closed; NO = normally open
3.2.4.2 Connect the analog outputs (optional)
Electrocution hazard. Always remove power to the instrument before making electrical
connections.
Table 4 Wiring information—relays
D A N G E R
Terminal Description
7 Relay 3, NC
8 Relay 3, common
9 Relay 3, NO
10 Relay 4, NC
11 Relay 4, common
12 Relay 4, NO
English 17