Hach sc100, User Manual

Page: 20 / 64

20
Installation
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
For Class 1, Division 2 Hazardous Location installations, refer to the Control
Drawing (
Figure 2 on page 10 ) for permanent connection requirements for the alarm
relays.
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 VAC, 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 connection to AC
MAINS circuits (i.e., voltages greater than 30V-RMS, 42.2V-PEAK or 60 V dc). Refer to
Figure 16 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 VDC Powered sc100
The 24 VDC sc100 controller contains three relays designed for connection to LOW
voltage circuits (i.e., voltages less than 30V-RMS, 42.2V-PEAK or 60 V dc). Refer to
Figure 16 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.