Omega Vehicle Security OMP-MODL - Manual (Page 48)

3... I NTERFACE M ODULES
U SING T HE OMP-MODL 3-24
Commonly, this fuse is blown during installation of 4-
20mA current channels where the power supply powering
the 4-20mA transmitter is accidently shorted directly
across the logger input channel. To avoid this
inconvenience, always check wiring prior to powering up
system power supplies.
MLIM-1; T
HERMOCOUPLE
A
PPLICATION
Thermocouple Connection:
To utilize an MLIM-1 channel as a thermocouple input, configure that
channel’s Interface Module Configuration Switch per Table 3... -4. Channels
configured as thermocouple inputs utilize three terminal strip connections
per input; Positive lead, Negative lead, and Shield.
Connect the thermocouple positive and negative (red in USA) leads to the
correct pair of terminals on the module terminal strip. Refer to Chapter 7 for
steps to generate a Terminal Strip Wiring printout for use in making field
wiring connections.
Polarity is critical.
Shielded thermocouple wire is recommended in electrically noisy
environments for optimum signal protection. If shielded wire is used, a
ground wire should be run from the MLAD-1 module Chassis Ground
(terminal strip connection #16) to an earth ground connection to conduct
away noise picked up by the thermocouple shield (Figure 2-8). Only one
ground wire is required as all of the Shield terminal strip connections are
interconnected within the logger and routed to the MLAD-1 Chassis Ground
terminal.
NOTE: Do not ground the shield wire at the sensor end away from the OMP-
MODL.
Thermo-
couple Icon
1 2 3 4 5 6
Terminal Strip
Thermocouple
Shield
Hi
Lo (Red)
ML055
Figure 3... -14: Thermocouple (and optional Shield) terminal strip connection