LMU-4200™ Hardware and Installation Guide
V1.0.9
November 13, 2010
Copyright ©CalAmp DataCom Inc 2010
- 21 -
CalAmp Proprietary & Confidential
2.4.1
Ignition and Inputs
The LMU-4200™ provides up to 4 inputs on its own and up to 7 with the ioPOD. These
inputs are protected from typical vehicle transients and can be directly connected to most
vehicle level logical inputs from 4 volts up to the vehicle power input level (typically 12
VDC). Their input impedance is approximately 10k
. One of these inputs is dedicated to
sensing the vehicle’s ignition status to provide for flexible power management. The other
two inputs may be used to sense vehicle inputs such as cooling unit operation, a hidden
driver “Panic” switch, taxi on-duty/off-duty meter status or many others.
The ignition input is pulled to ground through the 10k resistance, where the other inputs can
be configured to be normally High (i.e. pulled to +12v through a 10k resistor) or Low (i.e.
pulled to ground through a 10k resistor). The diagrams below show how to connect the
inputs in both a high- and low-biased configuration:
