Re:Mesa 7i77 differencial encoder connection.

A confirmation needed that Mesa 7i77 provides 5v out as one among 8 pins for encoders while my drive don't show it's needed in it's schematic diagram. Because as I said I am connecting mesa encoder inputs with my drive as it provides encoder outputs. My drive schematic shows that it's needed to connect only 7 wires for encoders

while it shows a strange connection "ZOC" (Encoder Z signal opening output) ?

I am assuming that it doesn't require 5v as drive will provide the same. But what about ZOC ? I am confused what is this. Below is a linked schematic diagram.

filebin.ca/1UQcJ0K53d6/schematic.pdf

Yes only 7 wires are needed: A. /A, B, /B and Z, /Z (sometimes called I, /I) and ground
(the 5V is power to run a standard encoder but your encoder signals are powered
by the drive so this stays unconnected)

No idea what ZOC is and the schematic is only downloadable on windows
systems (it installs an .exe file so those working on Billys farm, beware)
pastebin.ca might be a better choice.

Thanks again PCW ! And thanks for heads up as well !

I have uploaded the file at filebin.ca and updated previous post as well.

filebin.ca/1UQcJ0K53d6/schematic.pdf

The ZOC pins appears to be a open collector version of Z (index) signal
not sure what its good for

hey peter

just a quick question on this same issue this thread is the closest thing to what I want to know.

I have the same setup as above. I am using my servo drive to output the encoder outputs to the mesa 7i76 spindle encoder card.

as far as I understand the drive powers the encoders and the mesa card doesn't need 5v connected.

so here are the questions:

1 do I need to use a signal ground at all if using differential encoder signals?


2 I am currently powering the 7i76 5v logic power from 5i25 is that going to be a problem if connecting encoders?

I will attach a screen shot of the encoder stuff in the manual.

here is the manual I am asking about. I have a build thread that may be a better place to ask and if so just let me know and I will ask there.

awesome! thanks andy

that is a very good piece of info to know

I just checked between the 24v io ground on the mesa card and the logic power ground and they are within 1.5 v

So I am good to go.

connecting up now.

regards

Andrew

Becksvill wrote:

hey peter

2 I am currently powering the 7i76 5v logic power from 5i25 is that going to be a problem if connecting encoders?

I will attach a screen shot of the encoder stuff in the manual.

How many encoders and what current do they consume? from the manual...

EXTERNAL 5V POWER
The 7I77s 5V power for the analog, RS-422, and encoder section has an
approximately 650 mA current drain. Installed encoders, RS-422 devices, and load on the
analog outputs can increase this to up to 2A. This is in excess of the host FPGA cards
current supply capacity. So when longer cables or high power drain encoders are used, or
PC 5V is toward the low side, external 5V power should be supplied to the 7I77s TB1
connector. Both the FPGA card and the 7I77 have power jumpers that must be correctly
set to match the 5V power source (see hardware configuration section)