Add Z-Axis to my machine

can someone point me to the literature or thread explaining how to use the INDEX on encoders/resolvers to come to an exact home position every time? I'd like to explore doing this.

yes but do we need to couple the process with some kind of limit switch? It can't just be the resolver or encoder doing everything because if the power is turned off to the MESA card than the unit looses count, right? So I figured you hit the limit switch getting really close to home and then use the index from that point or something?

I'm just asking for an explanation of the process so I can understand it and possibly try to replicate it.

OK Guys, I got my 7i48 card in the mail and I'd like to ask for some help in creating my custom BIT file(s). I know that Andy advised I don't use these due to loss in resolution but it turns out they're 2400 PPR so that's pretty good. Yes they do NOT have INDEX signals but I can buy better encoders if this works and then create new BIT files for the newer encoders later. Right now these cost me a whopping 17 dollars each so that's pretty bad-ass cool. Additionally I found a major problem with my couplers. My encoder couplers (www.amazon.com/gp/product/B078VRZMNG/ref...A1THAZDOWP300U&psc=1) were broken completely in half on both X and Y so I have temporarily goop-glued them together until my new ones arrive. This will let me experiment with the cheap encoders while I decide if I want to get the more expensive ones.

I have viewed the primer (wiki.linuxcnc.org/cgi-bin/wiki.pl?Editing_MESA_Bitfiles) on making BIT files but it's only helpful to a certain degree. Is there a better example on how to do this? Some questions I'm running into are: I have a 7i48 and 7i42 card so how do I express both cards in my BIT file? How do I know which .vhd file to use as my example? There's no key or cross-reference to decipher what these names of source .vhd files are? Am I missing a README somewhere that explains this?

Is there a way to view an existing (already created) BIT file? I'd like to look at the ones I have because maybe I could just modify them. SVRM6_48 are the ones I use but I think these are already modified from the existing one in the 7i43 download that I got tonight.

I am a programmer so this stuff is pretty familiar to me I'm just missing some examples or primers or information that I seem to need to get to the next step. Any help the group can give is most appreciated!

Hi Guys, with Peter's help tonight I was able to compile my BIT file but without a basis I can't get my .hal and .ini file built properly. I need a starting point ...something to allow me a basic understanding of the 2 files in question and build from there. I was trying to use PncConf but I think that requires the .xml file to be generated with my .BIT file and I wasn't sure how to create the .xml file or the .pin file. So with that I'm stuck trying to look at sample configurations but they are not setup exactly like what I have.

I have my 7i43-4-u card with a 7i48 encoder card and a 7i42TA card. All I'm trying to do is see that my x encoder is registering movement. Right now it's the only encoder I have hooked up to the 7i48 card. I'm not powering my servos or my machine on, just powering up the MESA cards. I have 1 green and 2 yellow lights on the 7i48 card so I think something is wrong.

Can someone help give me a starting point for my new configuration? Generating the .xml and .pin files would probably help me to use pncconf and maybe from that start I can build.

Ha... I cloned the one .xml file from SVST4_6 for my SVST6_6 ... not sure if it's right but it made something work because I'm getting my encoder to show position now! -woohoo.

I'm sure I have a long way to go still but I have accurate movements being read by my encoders. I even figured out my scale 12000. So that's cool.

Guys I have made a lot of progress but I'm stuck on my Y encoder. It looks basically identical to the other one on the oscilloscope when I move it forward and backwards, but it's not reading. If I swap the blocks X & Y on the 7i48 board then Y reads just fine from the X encoder so I know it's not a board issue. I tried a different block thinking perhaps I had a bad pin in the 8 block but that's not it. I'm stumped. Is there a way to tune or look at what the MESA board is seeing? I tried the 3 pins to change from TTL to RS-224 but it didn't make a difference. I have tried "SHOW HAL CONFIGURATION" and watched all of the encoder pins but absolution nothing. No change everything stays zero.

I need some ideas to try next. Like I said I could understand this not working if the O-Scope showed something odd but it looks almost identical to the X axis encoder. It behaves the same etc...

Hi Guys,

Thanks for the help the other day in wiring up my new encoders ...once I set them into TTL (single sided) mode and eliminated the shield wire everything worked properly. I think I can still couple the shield wire with the ground but it doesn't appear to be affecting accuracy of the units the way it is now with just A+, B+, 5+, 0v. I do not have an index in these units.

So last night I decided to try tuning my new system that now has encoders. I found that things were very different from when I had the resolvers and in many ways they seemed a lot better while tuning the P value. I was able to go all the way up into 400 with P. Everything else was zero. Then I went to center my error with FF1 and found that FF1 had absolutely no effect. I took it up and up and up with my finger cautiously on the F2 the entire time. You won't believe this but I took it up to 400 just to see at one point. No effect ever. So what gives? My encoder scale is 12,000 so that's about the only other thing that I can think of why this FF1 would have no effect. -Suggestions welcome!

It is probably a hal pin connection problem with the PID inputs.
Post your current hal file and we can probably point it out.