4 alarms and relays – Hach-Lange SC 100 User Manual
Page 21
Installation
Alarms and Relays
17
3.4
Alarms and Relays
DANGER
Explosion hazard. Do not connect or disconnect electrical components or circuits to the
equipment unless power has been switched off or the area is known to be non-hazardous.
DANGER
Exposure to some chemicals may degrade the sealing properties of materials used in the
following devices: Relays K1, K2, and K3. Periodic inspection of these devices is
recommended to check for degradation.
The controller is equipped with three unpowered relays rated 100–230 V AC, 50/60 Hz, 5 Amp
resistive maximum. See the sensor manual for relay setup details.
3.4.1 Connecting the Relays
DANGER
Relay loads must be resistive. User must externally limit current to the relays to 5 Amps by
use of a fuse or breaker.
DANGER
Power and relay terminals are designed for only single wire termination. Do not use more
than one wire in each terminal.
The relay connector accepts 18–12 AWG wire (as determined by load application). Wire gauge
less than 18 AWG is not recommended.
The Normally Open (NO) and Common (COM) relay contacts will be connected when an alarm or
other condition is active. The Normally Closed (NC) and Common relay contacts will be connected
when an alarm or other condition is inactive or when power is removed from the controller.
AC Line (100–230 V) Powered sc100’s
AC line powered sc100 controllers contain three relays designed for use with high voltage (greater
than 30 V-RMS, 42,2 V-PEAK or 60 V DC). Refer to
Figure 15
for connection information. The
relay wiring compartment is not designed for voltage connections below these levels. Relays must
not be powered from the same wiring used to power the controller.
24 V DC Powered sc100
The 24 V DC sc100 controller contains three relays designed for use with only low voltage (less
than 30 V-RMS, 42,2 V-PEAK or 60 V DC). Refer to
Figure 15
for connection information. The
wiring compartment is not designed for voltage connections above these levels. Relay must not be
powered from the same wiring used to power the controller.