Sierra FLAT-TRAKTM 780S - Manual (Page 22)

Chapter 2 Installation Series 780S Instruction Manual
2-10 IM-78S-B
Alarm Output Wiring
Two alarm outputs (Low Alarm and High Alarm) are included on the
flow meter terminal block. The alarm outputs use optical relays that are
normally-open single-pole relays with one common connection.
There are two connection options for alarm outputs–the first with a sepa-
rate power supply (isolated) and the second using the flow meter power
supply (non-isolated). Use the first option with a separate power supply
if a specific voltage is needed for the alarm output. Use the second (non-
isolated) configuration if the voltage at the flow meter’s power supply is
an acceptable driver voltage for the load connected. (Take into account
that the current used by your alarm loads have to come from the flow
meter’s power supply.) In either case, the voltage of the alarm output is
the same as the voltage supplied to the circuit.
To use an external power supply for an isolated alarm output, con-
nect as shown in Figure 2-15 or Figure 2-17. To use the internally
powered, non-isolated alarm output connect as shown in Figure 2-16
or Figure 2-18. For a window alarm connect both outputs together.
ALRM COM
Load Load
LO ALARM (–)
HI ALARM (–)
AC or DC
power supply 1 2
15
16
NEMA 4X Enclosures
Figure 2-15. Isolated Alarm Output Connections
NEMA 4X Enclosures
ALRM COM
Load Load
LO ALARM (–)
HI ALARM (–)
COMMON
AUX DC PWR OUT
1 2
15
16
Figure 2-16. Non-Isolated Alarm Connections