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renraku
Tue 26 January 2010, 04:12
Hello everyone i have a question one doubt, there are 2 motors on the X, is possible that one of the 2 can be stopped and the other not, can happen ?

KenC
Tue 26 January 2010, 05:10
surely it can. if there is no power to any of the motors :)

Gerald D
Tue 26 January 2010, 05:14
...or a broken cable. Or one side hits an obstruction that is left on the rail. Yes, things can go wrong.

renraku
Tue 26 January 2010, 13:15
a dealer told me about when the stepper motor work high speed can stop and collapse without reason when it work fast, first motor X stop second motor go ahead can happen ?
The dealer advised me to use one driver dual power for both motors X axis

Gerald D
Tue 26 January 2010, 13:19
"one driver dual power" is not a solution. If one motor is obstructed, the other motor will still continue to move the gantry.

Do not worry about it....it makes no damage to anything.

KenC
Tue 26 January 2010, 23:21
Renraku, Ask your dealer how often does that happen? 20 times a day? 30 time an hour? Every time? or onece every 2000 operating hours? Get the statistic right & you can sleep better.

There are no 100% bullet proof solution in the real world. Even human have one leg stuck or collapse when walking/running/jumping/hopping at high speed... just how often it happens that's matter. ;)

Gerald D
Wed 27 January 2010, 00:04
If you fit the proximity sensors to the gantry, the systems detects when the gantry goes off the rails, and it does an E-stop shutdown of the whole system.

renraku
Wed 27 January 2010, 02:20
thanks

F2DVasek
Tue 18 May 2010, 12:32
Prompt how to synchronise please 2 engines on axis Х?
So that gradually did not warp a machine tool portal.

bradm
Tue 18 May 2010, 14:44
Vasek, stepper motors move a known, fixed amount for each step sent to them. So to synchronise, you simply send the same step pulses to each motor. MechMates generally use stepper motors.

For other types of motors, like servo motors, you need a feedback device - something that measures the motion of each motor. Usually this is a shaft encoder. The controller uses the encoder feedback to speed up or slow down the motors to keep them synchronized - and stop them at precise locations.

uirobot
Fri 04 June 2010, 10:59
CAN network will take care all your needs:)

bradm
Fri 04 June 2010, 12:15
Robotdigg, we have no evidence that CAN network systems will work with either Mach3 or EMC2, the PC based software we use to drive MechMates. Can you provide a parts list, approximate cost, and demonstration of a CAN network based system that can:

- Drive four stepper motors simultaneously.
- Independently vary the speed of the motors.
- Independently stop and reverse the motors after a specific amount of rotation.
- Drive three motors to different amounts of rotation in the same time period.

If you cannot provide this evidence, then no, CAN networks will NOT take care of all of our needs. Step and Direction signal based products are known to, however.

Gerald D
Fri 04 June 2010, 12:30
Brad, I share the view that "robotdigg" is spamming us with useless posts. But CAN is already in use for multi-axis CNC. See: http://www.iselautomation.de/products/product.php?lang=en&ID=p166 &
http://www.iselautomation.de/products/product.php?lang=en&ID=p63

bradm
Fri 04 June 2010, 13:32
Thanks, Gerald, that is interesting, and perhaps points towards the future.

Clearly, it's possible to move some of the intelligence of the kinematics out of the g-code interpreter, and into a motion controller. Similar technology has been used for theatrical rigging and tracking systems for a long time.

What I'm looking for is evidence that EMC2, Mach3, or a similar low cost commodity hardware and software solution has successfully integrated one of these types of systems. We've seen some failed attempts.

Given the increasing scarcity of parallel port technology, and the difficulty of forcing modern processors to operate in a synchronous, real-time mode with an I/O bus that is running several orders of magnitude slower than said processor (*), it would be really helpful to have a solution in this area.

So, while part of my note is clearly a warning shot about spamish behavior, I really would like to have someone positively answer the challenge :) I'm just not holding by breath ... yet.

(*) As evidenced by the increasingly horrible latencies experienced as these systems gain speed and processor cores.

uirobot
Fri 04 June 2010, 19:01
Hello there Gerald and Brad,

I am sorry that I am very good at technics.
I don't want to spam this wonderful forum, I admit I have that attempt before that, but it shows it's a very user friendly forum you can have one ad here.

I don't know Mach3 or EMC2, you may laugh at this, don't you?
Somebody asked me about CANOpen, I told them, CANOpen is complicated and have time lag.
My CTO told me that we run a UIM or UIrobot CAN protocol(Sorry, this is for explaination only), we simplify the CAN protocol and short it, so UIM CAN is faster than CANOpen. By using a CAN/RS232 Converter, the user don't need have knowledge about CAN, you just need to give it ASCII orders, it's transparent to users. The frequency is 1Mbps, I think it can satisfy your speed need.
There is time lag when you are running with CANOpen, so you don't achieve real-time and synchronously. UIM CAN simplified the CANOpen, it run real-time. You can give every stepper an address, if you want to control one of the motors, you just need to give commands to that address. There is a Global Command function (GSP;), so that you can control your stepper synchronously and individually.
I want to explain the cost here, not spam.
We are going to run a company in the U.S. very recently and the name is United Intelligence Technology Co.,Ltd. We not only adapt CAN technology to automation control, but also adapt it to message communication (Hospital Calling System).
Take your stepper control as a example:
You just need one stepper controller and one CAN/RS232 Converter. If you want to control 4 motors, you just need 4 stepper controllers and one CAN/RS232 Converter. The cost is 4*120USD plus 80USD. I don't know how much Mach3 or EMC2 software cost and your other brand stepper drivers.

We welcome to cooperate with Gecko I'd think.

Gerald D
Sat 05 June 2010, 01:27
UIrobot, an easy way for you be accepted at this forum......demonstrate your equipment on a working CNC system.

Gerald D
Sat 12 June 2010, 11:07
Kobus got his MM to run on UI Robot drives today (http://www.mechmate.com/forums/showthread.php?t=686).

smreish
Sat 12 June 2010, 13:59
Okay, that's pretty cool. Maybe a "drive on the stepper unit" itself is my next science project.

Sean