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CalAmp LMU-5541 Telematics Router Installation Guide

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Output 2: Standard Open Collector Relay Output

LMU-5541 Hardware & Installation Guide - PULS Wiki

Output 3: Standard Open Collector Relay Output

Output 4: Standard Open Collector Relay Output

Output 5: LED Driver Output 1

Output 6: LED Driver Output 2

iButton / 1 Bit Bus

iButton ID Support

1Wire bus with current boost for temperature sensors

4.7.1 Ignition and Inputs

The LMU-5541™ provides up to 7 High/low selectable inputs and one Ignition Sense input.. 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 seven 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

200K10k resistor) or Low (i.e. pulled to ground through a 100K10k resistor). The diagrams below show how to connect the inputs in both a high- and low-biased

configuration:

Sample Input Wiring

4.7.2 Open Collector Outputs

The LMU’s outputs are designed to drive external relays. These outputs provide a high-current, open-collector driver that can sink up to 200 mA each. These drivers

may be used to drive external relays that can then control vehicle functions such as door locks, fuel shut-off valves, sirens and lights. If additional current is required

to drive the relays, external circuitry can be added to source the current. This diagram is a typical use of an output to drive a relay.

https://puls.calamp.com/wiki/LMU-5541_Hardware_%26_Installation_Guide

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