Frequently Asked Questions

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General Questions Questions Related to Specific Gage Products Can't Find an Answer?

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Questions Related to Specific Gage Products

Q. We would like to have a 4 channel, 20 MSPS acquisition system using two CompuScope 220 Cards. The system must trigger on any one of the four channels, as the error pulse can arrive on any of these channels. Is it possible?

A. There are two solutions to doing such triggering on a CS220 multi-card system :

• Use FOUR CS220 cards in a Master / Slave mode.

Each board will be in the single channel mode. The trigger from the 4 CS220 boards is wire-ORed in a multi-card system (this is standard on the CS220 multi-card), so whenever any one of the four boards is triggered, the whole system is triggered.

Standard GageScope Multi-Card software will work with the system. This solves your customer's problem.

• Use TWO CS220 cards in a Master / Slave mode.

CS220 allows you to trigger in an (A OR B) mode. This will only work if the inputs are usually higher than the trigger level.

This means this will only work if the pulses are negative-going pulses. In the case of positive going pulses, this method of triggering will not work.

The reason for this is that the (A OR B) is performed by tying together the open collector outputs of two comparators. If any of the comparators has a LOW output (i.e. the input signal is smaller than the trigger level), no transitions occur upon another input crossing the trigger level and hence no trigger event is detected.

If you can guarantee that the pulses will be negative-going, this method will work and standard GageScope Multi-Card software will work with this system.

If, on the other hand, your customer can guarantee that his pulses will always be positive-going, we can modify the CS220 hardware to accommodate this and provide a system which will trigger on any of the four positive going pulses.

We built just such a system for the Space subdivision of Honeywell Corporation in the United States. The cost of this modification is US$400 per board.

The standard GageScope Multi-Card software will work with this modified system. The only exception will be that the trigger slope will be inverted: i.e. when you set positive slope a negative slope triggers the system and vice-versa.

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