Model 2000-SCAN Scanner Card User's Manual
Section 3: Operation
2000-SCAN-900-01 Rev. A / April 2018
3-15
Current shunt locations
The following figure shows the locations for the user-installable current shunts.
Figure 23: Current shunt locations
Recommended current shunt values
Hole spacing on the circuit board is intended for 1/4 W resistors. The resistance value depends on
the current you are measuring; a 1 kΩ resistor should be optimum for many applications. A 1 kΩ
resistor will allow you to switch currents up to 15 mA without exceeding the power rating of the
resistor.
For larger currents, decrease the shunt value. Conversely, the shunt value can be increased for
smaller currents.
Do not exceed the maximum card signal levels:
DC signals: 110 VDC, 1 A switched, 30 VA maximum
AC signals: 125 VAC
RMS
or 175 VAC
PEAK
, 1 A switched, 62.5 VA maximum
Current measurement math
The current through each shunt resistor can be calculated as follows:
Where:
•
I = current being determined
•
V = voltage measured by the multimeter
•
R = shunt resistance value
Instead of manually calculating current, set up a DMM6500 mx + b math function. Here, m = 1/R and
b = 0.
Refer to the
Model DMM6500 Reference Manual
for details on using math functions.