34
M2A Transmitter Operator’s Manual
8. Use the following recommendations to determine how to wire the M2A:
•
If Modbus connections will not be used and only the PWR/SIG connections will be used, use a two or
three conductor shielded cable or two or three wires in conduit for connections to the power/signal
terminal strip depending on whether or not the signal (S) terminal is used. The S terminal has a 4 - 20
mA output, but if you do not need to monitor this signal and do not connect to the S terminal to access
this signal, the M2A will still function completely.
•
If the PWR/SIG connections and one or more relays are used, route the connections to the M2A in
conduit. Use shielded cable in the conduit for the PWR/SIG connections and unshielded cable or
individual wires for the relay connections. Make sure any wire or cable used for relay wiring is
appropriately rated for the power that it will carry.
NOTE:
If shielded cable is used for the PWR/SIG connections, leave the cable shield’s drain wire insulated
and disconnected at the M2A. You will connect the opposite end of the cable’s drain wire at the
controller or device.
•
If the M2A will be wired into a Modbus network, see “Chapter 8: RS-485 Modbus Output” on page 61.
See Figure 30 below for field wiring connections to the M2A.
Figure 30: Wiring the M2A to a Controller and Alarm Devices
9. Re-install the control PCB (and ribbon cable if necessary). Be sure the ribbon cable is routed down below
the control PCB so it will not be damaged by the cover when it is screwed back on.
10. Secure the junction box cover to the junction box.
Table 9: Wire Size for PWR/SIG Connections
Max Distance to Controller
w/18 Gauge Wire
Max Distance to Controller
w/16 Gauge Wire
Max Distance to Controller
w/14 Gauge Wire
2,500 ft.
5,000 ft.
8,000 ft.
Alarm Device
Power
Fail Alarm
Device
Alarm 1
Alarm Device
Typical Alarm
Wiring Shown
See
Modbus
Wiring
RKI Controller
Terminals
(24 VDC) +
4 - 20 mA In (S)
(24 VDC) -
-
S
+
A
B
C
RS
4
8
5
PW
R
/S
IG
R
W
G
B
LE
L
See
Detector
Wiring
C
NC
N
O
AL
AR
M 1
C
NC
N
O
AL
AR
M
2
C
N
C
N
O
FA
IL
Alarm 2
Alarm Device
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