Know How

Two relays are connected to each connection point of the matrix – one for each pole of the high voltage. The tester can control each of these relays individually. This means that at each connection point you can choose from:

• the first pole of high voltage, or
• the second pole of high voltage
  .

In this way, it is specifically determined which pole should be at which connection point.

Test plan and test sequence

For the test, the setter creates a test plan. This consists of several test steps that are carried out one after the other during the test.

In each test step it is determined:

• which pole of the high voltage tester
• to which connection point is switched.

In this way, the connection points can be combined with each other as desired. It is possible to use each connection point against any other Test.

Flexible test combinations

In doing so, a test step not limited to just two connection points. In a single test step several connection points can also be connected to one pole at the same time and tested together as a group against another group.

The relay matrix thus enables a very flexible and freely configurable high voltage test, adapted to the respective device under test and test plan.

The relay matrix can also be easily designed for a four-wire measurement. For this purpose, two additional relays are required per connection point. A total of four relays are thus used per connection point. The higher effort arises because not only the test leads, but also the separate sense cables have to be switched during the four-wire measurement. This doubles the switching effort compared to two-wire measurement. The following picture shows an example of a relay matrix for four-wire measurement in a Resistance test.

Advantage of four-wire measurement

The great advantage of this measurement method lies in the automatic compensation of disturbing resistances. Line resistors, relay contact resistors and other contact resistors no longer influence the measurement result. This accurately captures the actual resistance of the test specimen. The result is a highly accurate and reproducible resistance measurement, regardless of the wiring or switching elements of the matrix.

In this way, a contact control (ladder break monitoring, contact monitoring) of the TEST VOLTAGE. Only if the device under test repatriated voltage is measured at the intended height, it is ensured that the TEST VOLTAGE actually correctly on the device under test . This feedback increases process reliability, especially in automated test sequences, as faulty contacts or interrupted connections are reliably detected.