Hach sc1000 - Manual (Page 30)

28
Installation
3.6.1 Relay card connections
DANGER
Electrocution hazard. Relays must either be wired as low or high voltage.
DANGER
Fire hazard: Relay loads must be resistive. User must externally limit current to the
relays to 5 Amps by use of a fuse or breaker.
The relay connector accepts 18–12 AWG wire (as determined by load application). Wire
gauge less than 18 AWG is not recommended.
If the instrument is equipped with the relay card option, the instrument will include 4
relays, each with one change over contact. In this configuration, steps 3, 4 and 6 in
To
make a relay card connection are not applicable.
The relays can switch maximum 250 VAC, 5A. Each relay can be configured for different
applications.
Figure 18 Expansion card ports
1 Relay card 6 mA output or input wiring information
2 Relay wiring information 7 mA output or input card
3 Field-bus or mA output or input card 8 mA output or input wiring information
4 Field-bus or mA output or input card wiring information 9 Main high voltage barrier
5 mA output or input card 10 Relay voltage barrier