Need Semi-Slim Scale Recommendation

[3Dogs]

So TTL is more plug/play then?

I guess it depends on what type of input your DRO is expecting.
If the display expects TTL (logic level) inputs, then you will need a differential receiver chip to convert RS-422 to TTL. If your display expects RS-422, then you can connect it directly. I don’t have any experience with this project myself, so I’m not sure what signals the display expects.

 

[3Dogs]

This adapter will take both RS-422 and TTL inputs:

DRO Adapter for Glass and Magnetic Scales V2

 

[ycroosh]

I guess it depends on what type of input your DRO is expecting.
If the display expects TTL (logic level) inputs, then you will need a differential receiver chip to convert RS-422 to TTL. If your display expects RS-422, then you can connect it directly. I don’t have any experience with this project myself, so I’m not sure what signals the display expects.

Most RS-422 decoder chips can handle TTL input (also called single ended). You simply leave A'/B' inputs blank. To use a differential (RS-422) scale with TTL input, you leave A'/B' unconnected. In practice, RS-422 matters when you have extremely long cable runs and very high data speeds (in Megahertz range). This is very uncommon in a DRO setup. You'd need to drive a sub-micron scale at multiple meter per second, and run the cables from the garage to the neighbors living room.
In the olden day, some scales needed differential signal, since they were passing analog sine/cosine pair to the display for interpolation, and any noise would kill accuracy. 5V quadrature signal running in a shielded cable, wrapped in metal shroud, is pretty close to bullet proof in a shop.
In short, RS-422 vs. TTL is a non-issue.

Hope this helps.

Regards
Yuriy

 

[RaisedByWolves]

Awesome, Thanks guys!

 

[dabear3428]

Most RS-422 decoder chips can handle TTL input (also called single ended). You simply leave A'/B' inputs blank. To use a differential (RS-422) scale with TTL input, you leave A'/B' unconnected. In practice, RS-422 matters when you have extremely long cable runs and very high data speeds (in Megahertz range). This is very uncommon in a DRO setup. You'd need to drive a sub-micron scale at multiple meter per second, and run the cables from the garage to the neighbors living room.
In the olden day, some scales needed differential signal, since they were passing analog sine/cosine pair to the display for interpolation, and any noise would kill accuracy. 5V quadrature signal running in a shielded cable, wrapped in metal shroud, is pretty close to bullet proof in a shop.
In short, RS-422 vs. TTL is a non-issue.

Hope this helps.

Regards
Yuriy

Yuriy, do you mean that your adapter will accept RS-422 or TTL without changes or do we need to order TTL scales and RS-422 does not help us?
Thanks for your help

 

[ycroosh]

Yuriy, do you mean that your adapter will accept RS-422 or TTL without changes or do we need to order TTL scales and RS-422 does not help us?
Thanks for your help

You can use either, and TouchDRO won't care. As far as do you need it - probably no...
5V single ended signal (what most scale vendors call "TTL") can transmit data 15m without any degradation, and up to 60m with acceptable degradation.
RS-422 is VERY important when you need to have hight-speed data transmission over a cable up to 1200m long. In other words, if you want to have your scales in the next town, you should definitely get RS-422 scales. For 2-5 m standard cable run in a DRO, single-ended TTL is more than enough.

Regards
Yuriy

 

[dabear3428]

You can use either, and TouchDRO won't care. As far as do you need it - probably no...
5V single ended signal (what most scale vendors call "TTL") can transmit data 15m without any degradation, and up to 60m with acceptable degradation.
RS-422 is VERY important when you need to have hight-speed data transmission over a cable up to 1200m long. In other words, if you want to have your scales in the next town, you should definitely get RS-422 scales. For 2-5 m standard cable run in a DRO, single-ended TTL is more than enough.

Regards
Yuriy

thank you Yuriy, i get all of that about signal integrity, my confusion was about would the RS-422 work out of the box with your system (provided i purchase the glass scale/mag scale version). as i understand you it does not matter to your equipment which scale I buy either will work.
thanks for the clarification.

also i have read all of the threads here and info on your site about scales and i gather that:
1. capacitive will work but are more trouble than they are worth.
2. cheap chinese magnetic tape scales are a crap shoot.
3. middle of the road magnetic are good to go.
4. just about any cheap chinese glass scales are good to go just take a lot of room and have to be shielded from liquids.

I have a second hand Grizzly g0758 (the price was right) and due to its small size, glass scales will be difficult to fit on my X axis without compromising my Y axis travel. I'm thinking that my plan is to buy a set of cheap glass scales and try to fit them to my mill (using your touch DRO) and if i cannot get the x scale to fit i will purchase a mid priced magnetic scale (the smallest that i can find/afford).

any additional guidance?

have you have any experience with integrating the spindle DRO with your system, i have a hard time reading that thing and am thinking it would be easier if it was summed with the column and displayed on the DRO.

 

[ycroosh]

thank you Yuriy, i get all of that about signal integrity, my confusion was about would the RS-422 work out of the box with your system (provided i purchase the glass scale/mag scale version). as i understand you it does not matter to your equipment which scale I buy either will work.
thanks for the clarification.

also i have read all of the threads here and info on your site about scales and i gather that:
1. capacitive will work but are more trouble than they are worth.
2. cheap chinese magnetic tape scales are a crap shoot.
3. middle of the road magnetic are good to go.
4. just about any cheap chinese glass scales are good to go just take a lot of room and have to be shielded from liquids.

I have a second hand Grizzly g0758 (the price was right) and due to its small size, glass scales will be difficult to fit on my X axis without compromising my Y axis travel. I'm thinking that my plan is to buy a set of cheap glass scales and try to fit them to my mill (using your touch DRO) and if i cannot get the x scale to fit i will purchase a mid priced magnetic scale (the smallest that i can find/afford).

any additional guidance?

have you have any experience with integrating the spindle DRO with your system, i have a hard time reading that thing and am thinking it would be easier if it was summed with the column and displayed on the DRO.

Your summary regarding the scales is correct.

My spindle DRO looks like this:

The general idea works pretty well (the scale rides on two sets of bearings and the rectangular piece in the lower-left corner pushes it agains them, so ride height is very accurate. I will be replacing the scale with an EMS 5um scale, though.
I did this before realizing that I need to check for cyclic error; this is one of LMS scales that had >0.007" of error.

 

[protolancer]

thank you Yuriy, i get all of that about signal integrity, my confusion was about would the RS-422 work out of the box with your system (provided i purchase the glass scale/mag scale version). as i understand you it does not matter to your equipment which scale I buy either will work.
thanks for the clarification.

also i have read all of the threads here and info on your site about scales and i gather that:
1. capacitive will work but are more trouble than they are worth.
2. cheap chinese magnetic tape scales are a crap shoot.
3. middle of the road magnetic are good to go.
4. just about any cheap chinese glass scales are good to go just take a lot of room and have to be shielded from liquids.

I have a second hand Grizzly g0758 (the price was right) and due to its small size, glass scales will be difficult to fit on my X axis without compromising my Y axis travel. I'm thinking that my plan is to buy a set of cheap glass scales and try to fit them to my mill (using your touch DRO) and if i cannot get the x scale to fit i will purchase a mid priced magnetic scale (the smallest that i can find/afford).

any additional guidance?

have you have any experience with integrating the spindle DRO with your system, i have a hard time reading that thing and am thinking it would be easier if it was summed with the column and displayed on the DRO.

I'll be following this thread. I have a MODEL G8689 4" X 16" MINI MILLING MACHINE which is no longer made by Grizzly. It looks like the Grizzly G0781 4" x 18" 3/4 HP Mill/Drill replaced my mini-mill.

I'm going to add TouchDRO and magnetic scales. Awaiting the TouchDRO that I've ordered. I'm interested in in how you will attach your scales.

Bernd

 

[dabear3428]

I'll be following this thread. I have a MODEL G8689 4" X 16" MINI MILLING MACHINE which is no longer made by Grizzly. It looks like the Grizzly G0781 4" x 18" 3/4 HP Mill/Drill replaced my mini-mill.

I'm going to add TouchDRO and magnetic scales. Awaiting the TouchDRO that I've ordered. I'm interested in in how you will attach your scales.

Bernd

Hi Bernd, I will let you know, Y and Z are not an issue but i'm still getting my head around the X scale, I had it all worked out using the mag tape but am reconsidering due to info received here.

BTW how do you like your mill?
any pointers on dealing with the small working envelope?

David