11
(NO) contacts of the respective
relay. Unless specified otherwise,
SenTech Corporation recommends
the following relay connections for
building management systems:
1. BMS discrete input connected
through LOW, MAIN and/or
HIGH RELAYS, terminals 5
and 3.
Other External Connections
TB1 Outputs:
The IR-SNIF-1,2,3 is
designed to provide two standard 0-
10 volt analog outputs
or
two
optional 4-20 mA analog outputs
or
optional rs-485 interface for use with
ACC 070 SenTech COMM LINK PC
to Refrigerant Monitor Interface, or
ACC 065 SenTech Remote Control
Panel Interface. Refer to Figure 8
for a diagram of the terminal board.
Figure 8.
0–10 Volt Analog Outputs:
The IR-
SNIF-1,2,3 monitor provides two 0–
10 volt analog output proportional to
0–1000 ppm. Analog 1 provides a
signal proportional to the current
ppm level. Analog 2 provides a
signal proportional to the peak ppm
level measured. For applications
where the IR-SNIF-1,2,3 is installed
inside a mechanical room, the
analog 1 signal can be used to drive
an optional remote analog display at
the entrance to the room. This
signal could be used to provide an
analog input to building management
systems for remote monitoring of the
ppm level and for trending of levels.
This signal should NOT be used as a
replacement for discrete alarm relay
connections to a BMS. Analog
output connections are as follows:
1. Use twisted pair wire for
analog 1 connection, or four
conductor twisted wire for
both analog 1 and analog 2.
Typical low voltage solid
conductor wire is suitable for
this signal. Shielded cable is
preferred, but not always
required.
2. Route twisted pair wire into
the monitor and along the wire
harness from the back-plate
to the TB1 on the back-plate.
Secure
the
twisted
pair
periodically
to
the
wire
harness using tie wraps.
3. Connect the appropriate wires
to TB1-6, analog 1 plus, TB1-
7, analog 2 plus, and TB1-8,
reference ground.
4–20
mA
Optional
Analog
Outputs:
The
IR-SNIF-1,2,3
monitor provides optional 4–20 mA
analog outputs in place of the
standard 0-10 volt analog outputs.
To identify whether a monitor has 4-
20 mA analog output installed,
E
a
rt
h
G
ro
u
n
d
A
C
L
in
e
I
n
A
C
N
e
u
tr
a
l
In
1 2 3 4 5 6 7 8
A
n
a
lo
g
1
(
rs
4
8
5
T
X
)
A
n
a
lo
g
2
(
rs
4
8
5
G
N
D
)
A
n
a
lo
g
G
N
D
(
rs
4
8
5
R
X
)
Summary of Contents for IR-SNIF-1
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