Cirris 4200 - 24 Four-Wire Kelvin Testing

Four-Wire Kelvin Testing
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24. Four-Wire Kelvin Testing
To measure resistance, the tester sends a current through a wire and measures how much the voltage drops. It then
calculates the resistance using Ohm’s Law. Since voltage is measured through the xturing, any resistance caused by
xturing is included within that measurement. four-wire Kelvin testing eliminates the resistance of xturing and can
measure resistances down to .001 Ohm. The cost of this measurement accuracy is that twice as many test points are
required.
The four-wire measurement requires two correctly paired test points for every connection.
● One test point supplies current (referred to as “force”)
● The other senses voltage (referred to as “sense”)
For the purpose of four-wire testing using the 4200 Series, test points are considered either Type 1 (T1) or Type 2 (T2) points.
The tester uses T1 points as either force or sense; it uses T2 points as the compliment. Each four-wire pair from the tester
must have one of each point.
The following illustration shows a common way wires attached to the T1 and T2 test points could connect to the pins and
cavities in the mates-to-DUT connector.
On a 4200 Series tester, you can tell which type each test point is by probing the point while setting up a Learn.
1. From the Main Menu, press Create New.
2. From the Learn menu, press Edit Learn Settings, then press Components.
3. In the Components menu, press Learn Four-Wire and press OK. (Press OK again to return to the Learn menu.)
4. With only the xturing attached to the tester, press Learn Attached Device. A window will appear instructing you to
Attach Four Wire Fixture. When this window appears, touch the tip of the probe to a pin on your connector. You will
hear a tone and see a window specifying if the point is Type 1 or Type 2.
Note: Once the test program is Learned with four-wire included, the netlist will only show one test point of each four-wire
pair. It will count the rst test point it nds. This means If the points are wired in numerical order, the tester will count every
other point. (J1-001, J1-003, J1-005…) If you want the tester to list each test point in numerical order, you will need to
to tester
to tester
Device Under Test
Fixturing