Omega Vehicle Security OMP-MODL - Manual (Page 51)

3... I NTERFACE M ODULES
U SING THE OMP-MODL 3-27
APPLICATION NOTES; DC Voltage Channels
Channel Isolation:
The negative terminal of MLIM-1 channels configured as DC
Voltage inputs are isolated from the OMP-MODL circuit ground by a
22Kohm resistor (see Figure 3... -12).
Common Mode Input Range Considerations:
To prevent saturation of the input amplifier stages and erroneous
readings, no voltages should be applied to any input terminals that
are greater than 4.0V above or below circuit ground. If the signal
being measured is not connected to the OMP-MODL circuit ground
(ie `isolated’ supplies are used), common mode input voltages up to
32 V can be accepted. Voltages above this level can be lethal and
should not be applied to the OMP-MODL. Supply isolation can be
achieved by allowing the OMP-MODL to run from its internal
batteries (rather than an external source).
Multiple Measurement Nodes on a Circuit:
When measuring different voltage points from a common circuit with
multiple channels (of one or more Interface Modules), measurement
errors from induced ground currents can exist. Single ended
measurements may be required. Consult the factory for application
assistance.
MLIM-1; DC C URRENT ( M A-LO) A PPLICATION
The MLIM-1 can accept DC Current within the ranges specified in Table 3... -3. To
utilize an MLIM-1 channel as a DC Current input, set that channel’s Configuration
Switch per Table 3... -4 as a mA-LO Channel.
As shown in Figure 3... -12, when mA-DC is selected with the hardware
Configuration Switches, a precision 100 ohm burden resistor is enabled. The input
signal is measured as a voltage across the shunt resistor.
TIP: For best accuracy and absolute resolution, utilize
the lowest range possible that will cover the input signal’s
dynamic range without over-ranging.
Signal Connection (all Current Ranges):
Interface Module channels configured as mA-LO inputs provide three
terminal strip connections per input; Positive lead, Negative lead, and
Shield.
Connect the mADC signal positive and negative leads to the correct pair of
terminals on the module terminal strip (Figure 3... -16).
Refer to Chapter 7; HyperNet Programming for steps to generate a
Terminal Strip Wiring printout for use in making field wiring connections.
Observe polarity or the output signal will be reversed.
mA-Lo Icon