Installation guide

LMU Users Guide
V1.0.6 December 10 2009
Copyright ©CalAmp DataCom Inc 2009
- 13 - CalAmp Proprietary & Confidential
4.2.1.1 Changing the Input Bias
For some LMU products, the input Bias can be controlled by S-Register 158 (or Parameter
1024, Index 38). Each bit of this register is assigned to a specific input. If the associated bit is
set, then the input is biased high, if the bit is cleared, then the input is biased low. The input
to bit mapping is as follows:
Bit
Input
S-Register Mask
0
Not Used
1
Input 1
2
2
Input 2
4
3
Input 3
8
4
Input 4
16
5
Input 5
32
6
Input 6
64
7
Input 7
128
For example, to bias inputs 1, 3, 5 and 7 high and bias 2, 4 and 6 low, you would use the
following 7 commands:
AT$APP PARAM 1024,38,2,2
AT$APP PARAM 1024,38,4,0
AT$APP PARAM 1024,38,8,8
AT$APP PARAM 1024,38,16,0
AT$APP PARAM 1024,38,32,32
AT$APP PARAM 1024,38,64,0
AT$APP PARAM 1024,38,128,128
Alternatively you could have used a single command of:
ATS158=170 (i.e. 128+32+8+2)
4.2.2 Motion Sensor Input
Some of the LMU products support an internal motion sensor as one of the discreet inputs.
In this case, the LMU detects motion when the input is in the High state. If the LMU does
not detect motion, then the input will be in the Low state. The sensitivity of the motion
sensor input is controlled by S-Registers 175 and 176.
4.2.3 Power State Input
Some of the LMU products can detect if they are using external power or if they are using
their internal back-up battery. If they are using external power, this input will be in the Low
state. If they have switched to the internal battery, then the input will register in the High
state.
4.2.4 Battery Voltage Critical Input
The LMU-1100 and LMU-1200 have a built in low battery threshold of 3500mV, which is
tied to a discreet input. If the battery level is above the threshold, then the input is in the
Low state. If the battery level is below the threshold, the input will be in the High state.