pci 6601 for decoding renishaw and new encoder

[jimmyinct3]

i have a pci 6601 and scb 68 that was recommend for decoding a renishaw encoder.

it works great for determing the position of the renishaw.

the renishaw encoder type is

rgh24x30a00a

http://www.renishaw.com/en/rgh24-linear-encoder-system--6444

i would like to try the pci 6601 on a similar encoder.

With this new encoder, im not seeing any output from the pci 6601. 

I can see the pulses on the oscilloscope so im alittle confused.

The pulses appear center around 2.5 volts and are around 1v in amplitude.

In the same manner as with the renishaw, B- goes to counter 0 aux, a- to 0 source, and grond to ground.

I believe the particular renishaw has a 1v peak to peak sinusoid pair (sin / cos).

The new servo has a build in encoder with one volt peak to peak sinsuoid centered at 2.5v.

Any ideas on why no counter number is showing?

Message Edited by jimmyinct3 on 11-14-2009 05:57 PM

[HeatherBaker]

If the signal is centered around 2.5V as mentioned, then it sounds like you will have difficulty meeting the TTL thresholds for hi/low. A TTL input signal is defined as "low" when between 0 V and 0.8 V with respect to the ground termina...  Scope both encoders and compare the signals that you are seeing on both.  What are the differences?