1.3.2 Behind The Front Panel
The internal functionality of the AT3600 tester is summarized in the following figure:
You do not need to know how each block functions in order to use the tester. The following explanation is included for readers who wish to know more.
These are the spring-loaded ATE pins that can be seen on the top surface of the tester.
Each node is made up of two contacts - a ‘power’ pin, and a ‘sense’ pin - forming a Kelvin pair.
Relay Switching Matrix
The purpose of the relay-switching matrix is to connect the selected test source and measurement circuits to the particular nodes required in the test.
The matrix is a crucial component in the performance of the AT Series tester. It is made up of very advanced, high speed, high voltage reed relays, capable both of holding off the 7000V test voltages used in Hi Pot tests, and of accurately switching the very small voltages and currents encountered in other tests. (Lower voltage rating relays are used on the AT1600).
The switching of the relays is carefully controlled by the processors so that there is no arcing across the contacts. This means that the life of the relays can be guaranteed to last for many millions of switching operations.
The AT Series Testers are based on a two-processor design:
A standard microprocessor which acts as controller, and also drives the relay matrix, the keyboard and display, and the various interfaces.
A fast digital signal processor that controls the test sources and performs the measurements.
There are six different test sources within the AT3600.
The processors select which one is to be connected to the relay matrix, as each test is executed.
The AT3600 tester contains a variety of circuits, capable of performing all the following measurements:
- Voltages from less than 1mV to greater than 7000V,
- Currents from nano-amps to amps,
- DC and harmonic analysis,
- RMS, mean-sense, wattage and VA analysis,
- Transient capture,
Again, the processors select which is appropriate for each test as it is executed.
Keyboard & Display
The front-panel of the tester contains an LCD graphics panel display, three LED’s, and a membrane type alpha-numeric keyboard.
To give the greatest versatility and ease of use, the front panel ergonomics are based around four ‘soft-keys’, which are situated to the right of the display. During operation, the display provides titles for these keys, allowing them to change with the context, so that the operator is presented with only the key choices that are relevant at that point in time.
These include the Remote, Bar Code, Auxiliary and Server Ports located on the rear panel, and the User Port that is at the rear of the top surface.