What is the maximum input frequency coming from quadrature encoder?

[jimmyjimmy2000]

Hi there,
I would like to know, what is the maximum frequency ,comming from quadrature encoder, which 6601 can measure without error. And could you provide me how 6601 measures encoder signal under x1,x2 and x4 mode. Can I use frequency converter to improve me position measurement with 6601? And if so, can you provide me how to do this in detail .Thanks.

[Filipe A.]

Hello;

Since the maximum timebase that can be used on the 6601 counter board is 20MHz, a good rule of thumb is to have the input pulse train to be masured not exceeding 20MHz/2. That will guarantee the counter to catch all pulse edges of the incoming pulse train.

Regarding your second question, the 6601/6602 Users Manual has a good description about the differences about modes x1, x2 and x4.

Hope this helps.
Filipe A.
Applications Engineer
National Instruments