Controlling two VXMs LabVIEW and other questions

[Nnaedoziem Aririele]

Hey Cliff

     I was wondering if there was a way to run two seperate VXMs at the same time. I can't seem to do it on LabVIEW which requires me to toggles between ports.

Also I was saw on our invoice that our belt drive, the PK296B2A-SG10 doesn't have it's correct specs listed on the VXM manual. From the invoice it states that it is 10:1 and has an advance per turn of 10mm (1/2 inch). Could you help me find or convert this into it's speed at 1000 SPS and into it's advance per step at 1000 SPS (conversion to mm or inches whichever one is easier). I tried what you told me yesterday and it was not .0025mm per step and not 2.5 mm/sec

Also when you set the zero position for motors, do they remember that or is that info stored in the VXM which resets that info each time it's turned off?

[VelmexControls]

By any chance is this project the one that has a vertical belt drive with a brake on the motor?

Although it is possible to run 2 separate VXM's at the same time it does require 2 separate ports and some sort of programming to coordinate and control the system as a whole.

A belt drive travels 100mm per rev if it is directly driven with a normal 0.9degree/step motor (or  0.25 mm/step or 0.00984251968503937007874015748031 inches/step)

Now if you have a gearbox then you have to multiply that ratio by the above values (for instance your 10:1 gearbox would result in)
0.25mm/Step * (1/10) = 0.025mm/step or 0.000984251968503937007874015748031 inches/step

And as the Users Manual P.11 shows (Look in COSMOS under "Help--->Documentation--->Users Manual") that
Linear Speed = Advance per step x steps per second
Or in your case 0.025mm/step * 1000steps/sec = 25mm/sec (or 0.9842519685039370078740157480315 inches/sec)

Once you set the zero position it will be zero only until you turn off the control, when it is turned on where-ever the slide happens to be will be zero unless you move it to a known point and set that as zero

[Nnaedoziem Aririele]

I honestly don't know if there is a brake on it. I work for Texas Instruments though so if it says on your order copy that it has a brake on it, then it does. Judging by the invoice it appears that we ordered two of these. One lies on the floor and that one has two limit switches and on the 296B2A-SG10, it says that it moves 0.18 degrees per step. I assume since on the invoice both the vertical and horizontal use the same motor they have the same specs? The vertical one is back at Velmex to be shortened because it doesn't fit into our lab. 

Is there a way to confirm that the 296B2A-SG10 is indeed 0.18 degrees/step?

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[VelmexControls]

Since it is back at Velmex then yes I can be fairly sure that this job is indeed the one with a brake on it.
I personally tested the system and left a demo program in it and had all the settings pre-configured.

Since I do not have access to the order at the moment I will have to go with my memory (gets fuzzier the older I get *LOL*)

I am working on a series of tutorials right now to more detail how to calculate these things but trust me for now that the values you need are based from P.11 of the Users Manual (as Seen if you run COSMOS and click "Help--->Documentation--->Users Manual")
1 Motor rev = 400 steps

Linear Speed = Advance per step x steps per second

Rotary Speed = Advance per step x steps per second
Steps per second ÷ 400 = rev/sec

In your case with a 10:1 Gearbox the "Magical Numbers" you need are
Speed = Inch/Sec divided by Advance per step
Example 1 inch = 25.4mm divided by .025 mm per step = 1016 steps
and the same if it were 1 inch a second

Being a belt drive I would not exceed 3200 steps per second (all bets are off exceeding that speed)

[Nnaedoziem Aririele]

Thanks for that info. So for now, we don't know how much my particular pair of 296 rotate per step? Since you've given me all the equations I need, I just need that magical per step unit that the other motors I am using need. Is there someone at Velmex I could talk to that could check in on the 296 specs for me

[Nnaedoziem Aririele]

Hmm actually disregard my last request. I just read through your previous post, I'll use those equations with the 0.18 degree per step spec and see if that fixes things

[Nnaedoziem Aririele]

Yeah is there a way to convert .18 degree/step to mm/step? I can use the 10:1 gear ratio to finish all my needed measurements. that motor also uses 10mm advance per turn. 

[Charles Emrick]

Although Cliff goofed a lil bit the formulas are all there
Motor = 0.18 degrees per Step (Since it is not a "M" motor, which is where Cliff goofed)
VXM = 1/2 step per step
Gearbox = 10:1
Belt Drive = 100mm/Rev
So its Simple
Motor * VXM * GR * RevTravel or
(200 Steps/Rev) * (1/2 Step/Step) * (1/10 GR) * (100 mm/Rev)
or
In your case (400 steps/Rev) cause VXM
10mm/Rev cause belt drive
and it becomes
0.025 mm per Step

I don't think I need to teach you how to translate MM to Inches

[Nnaedoziem Aririele]

Thanks! Is the speed 2.5mm/sec?

[Nnaedoziem Aririele]

Oh the motors and slide only understand integer stepping correct?

[Charles Emrick]

Yep and Yep
Decimal points are thrown out
AKA: a command can only be like "I1M1000" and not "I1M1000.06" cause the .06 will be tossed

[Nnaedoziem Aririele]

Thank you very much. 296 is working perfectly now

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[Nnaedoziem Aririele]

Quick question. What is Echo on and off when it comes to the VXM?

On Wed, Aug 21, 2013 at 1:02 PM, VelmexControls <velmexc...@gmail.com> wrote:

[VelmexControls]

Echo On = VXM will "Echo" (Or send back) each character that receives
Echo Off = VXM does not send back the characters