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Offline jve

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ab pulse train output
« on: May 05, 2011, 12:31:44 PM »
hi guys i have a plc allen bradley micrologics 1400 and it says that on out put 0,1,2 has a pulse train output (100khz) that can drive the axis so i was thinking if i can use this to drive the axis my servo drive have the step & dir input is this possible ? my intention is so i dont use the parallel port i make 1 ethernet cable to communicate with the plc and the plc will do all the work like i/o and the axis drives too

Offline Hood

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Re: ab pulse train output
« Reply #1 on: May 05, 2011, 02:33:25 PM »
I think that would be CW/CCW that your drive would need. If it does then your PLC should be able to drive it.
Hood

Offline jve

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Re: ab pulse train output
« Reply #2 on: May 05, 2011, 03:01:52 PM »
i shoud have the cw/ccw although i never used that but another thing that i dont know is how to connect the wiring from output 0 should i put a wire to cw and from the com to ccw i never done this before  ???

Offline Hood

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Re: ab pulse train output
« Reply #3 on: May 05, 2011, 03:07:17 PM »
Afraid I dont know, you would have to refer to your PLCs manual.
Hood

Offline jve

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Re: ab pulse train output
« Reply #4 on: May 05, 2011, 03:12:14 PM »
many thanks for your help hood i will take a look to the manuall so i will get a bit more  ???

Offline Hood

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Re: ab pulse train output
« Reply #5 on: May 05, 2011, 03:13:31 PM »
Ha ha yes the manuals take quite a bit of reading before you start to understand them ;D
Hood

Offline kf2qd

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Re: ab pulse train output
« Reply #6 on: May 06, 2011, 04:38:09 PM »
I don't think you'll have much luck driving the motion outputs of the plc from Mach. The high speed functions only work when you are running a motion program from the inside PLC program. When you are using them as normal outputs (which they really would be in this case) there is some limitation as to how fast they can change state. The motion control program that resides in the PLC runs along side the normal PLC I/O function and runs somewaht independent of the normal PLC I/O Scan.  I have seen normal PLC scans of 500-600 per second, where you are looking for output frequencies in 100,000 times a second.

A normal PLC  runs kind of like this - Read the inputs, go through the program logic setting the outputs, write the outputs. The Micrologix PLC's I used did this about 500 times a second. There is some other overhead in the process to check for errors and such...

Offline jve

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Re: ab pulse train output
« Reply #7 on: May 07, 2011, 12:20:48 PM »
may be you are right i never done this before i am trying to do this cause of certification my problem is that i cannot find any breakout boards with ce certification so i was thinking the option with the plc
another thing is how i can make a machine running with mach3 with ce certification i been searching for days now trying to find breakout boards with ce certification
is there any way to do this?
I don't think you'll have much luck driving the motion outputs of the plc from Mach. The high speed functions only work when you are running a motion program from the inside PLC program. When you are using them as normal outputs (which they really would be in this case) there is some limitation as to how fast they can change state. The motion control program that resides in the PLC runs along side the normal PLC I/O function and runs somewaht independent of the normal PLC I/O Scan.  I have seen normal PLC scans of 500-600 per second, where you are looking for output frequencies in 100,000 times a second.

A normal PLC  runs kind of like this - Read the inputs, go through the program logic setting the outputs, write the outputs. The Micrologix PLC's I used did this about 500 times a second. There is some other overhead in the process to check for errors and such...

Offline Hood

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Re: ab pulse train output
« Reply #8 on: May 07, 2011, 02:45:08 PM »
Ah sorry I was thinking you were to be controlling the axis totally via the PLC, maybe for something like a single output, or series of individual outputs from Mach to move the motor a set amount such as on a tool changer or an indexer. I didnt realise you were thinking of using it to use with Mach for synchronised axis motion.

As for breakouts afraid I dont know of any with CE markings, maybe some of the European manufacturers will do them.

Hood