FEC200 VZ and VBR Tests
VZ and VBR are synonyms. You can use them interchangeably.
This test is pretty straightforward. The simple example below is typical of the way it is usually used.
- TESTn VZ 10MA >9.5V <10.25V
Nevertheless there are a few things you should know. For example:
VZ stores its reading in a variable LASTVZ each time it is called. It also sets FIRSTVZ the first time it is called in any sequence. This allows some other tests, such IR and DRIFT to lookup these values. This is the test that is most critical relative to accuracy, particularly for low voltage zeners. For this reason we have provided a means for you to "tweak" the 16.383V or the optional 24.574V scale to get performance even better than our specified long term accuracy.
By editing the CUSTOM.TXT file you can set "constants" that will be added to readings on this scale to compensate for zero offset and multiplied by the reading to correct the scale factor.
After CUSTOM.TXT is edited, MAXX must be restarted for these changes to be put in effect. Of course, this is only a concern if you have done the editing within MAXX using the DOS command.
It is very common to use conditional jumps with VZ tests so that you can jump over other related tests for a given voltage if the part doesn't fall within that voltage range.