Document # 31-0008
LM2_Manual_1.4.doc
34
5.2 Analog Inputs
The LM-2 has 4 analog inputs for external 0-5V sensors. Each input has a
corresponding positive lead (+) for the signal and a negative lead (–) for the ground
signal source. It is important to wire both of these leads to get accurate measurements.
5.2.1
Enable/Disable Analog Inputs
1. Press and hold the
Mode
button to go into the Configuration Menu Screen.
2. Select
Analog Inputs
and press the
Enter
button.
3. You will not have the option to Enable/Disable the Analog Inputs.
5.2.2
Wiring Analog Inputs
The LM-2’s inputs are differential. A differential input does not measure a signal relative
to electrical ground. Instead it measures the relative voltage between two signals. That
is, it does not measure the '+' signal in relationship to ground, but in relationship to the '-'
signal. It measures the 'difference' between them (hence the name differential input!)
Below you will find diagrams that should better illustrate the correct way to wire in
external sensors. Please note that the + lead is signal positive, NOT power.
