Adam Equipment ACBplus Series, Руководство по обслуживанию

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@Adam Equipment Company 2005 20
increased. Typical load cells show 20-30mv of signal if the excitation voltage is
10volts and the load cell is fully loaded.
Most load cells used in scales are not as simple as this example. They have
additional resistance elements added to compensate for temperature variations and
to set the outputs to correct voltages. The circuit of a typical load cell is shown
below.
350
oh
m
35
0 o
hm
350
oh
m
35
0 o
hm
A
B
C
D
lo
w
o
hm
lo
w
o
hm
temperature
correction
temperature
correction
+E
-S
-E
+S
BALANCED BRIDGE
10 VOLT POWER
SUPPLY
Vout = O VOLTS,
BS AND -s
A method to check the basic function and integrity of a load cell can be done using
ohmmeter and voltmeter with up to a 10volt power supply.
Before the load cell is connected to the power supply use the ohmmeter to measure
the resistance between the wires. Typical resistance values are:
+E to -E 410 ohms ±30 ohms
+S to -S 350 ohms ± 2 ohms
+E to +S or any other combination similar approximately 270 ohms.
If the load cell has Sense connections in addition they are connected to the
excitation internal to the load cell.
Connect the load cell +E and -E to a power supply, typically 5 volts. Never use more
than 12 volts as it may damage the load cell.
Measure the voltage bS and -S.
With no load the voltage should be approximate 0mv ± 1mv.