Ohaus Corporation www.ohaus.com
9
Defender
™ Series Bases Service Manual
Figure 1-3. Route of electrical Load Cell input and output through Wheatstone Bridge circuit.
A Load Cell is a force sensor, which receives a voltage (excitation) from a regulated power source in the
Indicator, and sends back a low-voltage milli-volt (mV) relative to the force applied. The Load Cell signal is
read by the Indicator, which converts it to a numeric value and shows it visually. This output value increases
as weight is loaded to the Load Cell.
For example, a 500kg Load Cell with 2mV/V output and 5V excitation would have a change of 0.02mV per kg
change in the load, that is, 10mV/500=0.02mV per kg. At a load of 250kg the signal voltage would thus
increase by 5mV from the value measured at no load.
1.11
Load Cell Connection
Type1. For models i-D3K1S, i-D6K1S, i-D15K1R, i-D30K1R, i-D60K1L bases
FUNCTION
WIRE COLOR
+ Excitation
Blue
- Excitation
Black
+ Signal
White
- Signal
Red
+ Sense
Green
- Sense
Grey
Shield
Yellow
Tension
Tension
Compression
Compression
+Excitation
(Supply)
–
Excitation
(Supply)
INPUT(volts)
LOADCELL
2 mV/V
Strain
Gauges
4 strain gauges
connected as a
Wheatstone
Bridge
OUTPUT (milli volts)
+
Sig
–
Sig
