- Configuring LinuxCNC
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- Outputting a pulse width for velocity servo control possible?
Outputting a pulse width for velocity servo control possible?
21 Nov 2017 09:41 #102126
by tecno
Replied by tecno on topic Outputting a pulse width for velocity servo control possible?
Read this!!!
forum.linuxcnc.org/27-driver-boards/3011...ead-of-10v-out#67442
Do not make same mistake as I did = got screwed !
forum.linuxcnc.org/27-driver-boards/3011...ead-of-10v-out#67442
Do not make same mistake as I did = got screwed !
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21 Nov 2017 09:55 #102127
by andypugh
I would be very wary of swapping out high quality drives and motors, properly engineered for your machine by the manufacturer with cheap generic drives from China.
But, if this is a machine using DC servos, I think that the parallel port is an odd choice of interface.
Replied by andypugh on topic Outputting a pulse width for velocity servo control possible?
I am starting to rethink this a little seeing the prices on some of the new China drives out there.
I would be very wary of swapping out high quality drives and motors, properly engineered for your machine by the manufacturer with cheap generic drives from China.
But, if this is a machine using DC servos, I think that the parallel port is an odd choice of interface.
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21 Nov 2017 09:57 #102128
by andypugh
Replied by andypugh on topic Outputting a pulse width for velocity servo control possible?
(I think there may be some confusion, partly based on me assuming that we were talking about spindle control here, whereas it seem that you are talking about axis control).
There are Mesa firmwares with many more PWM channels than you will need.
There are Mesa firmwares with many more PWM channels than you will need.
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21 Nov 2017 19:05 #102152
by DaOne
Replied by DaOne on topic Outputting a pulse width for velocity servo control possible?
Andy, this is a 1995 machine that is very old in terms of tech. It has almost no memory and no look ahead. I am looking to gain higher speed and high speed machining. The DC servos that are in this machine are notorious for failing due to brush dust and coolant ingress. Parts are impossible to get when it comes to the electronics of this old machine. It's even too old to do the upgrade offered by Haas for 10k.
The axxis are all driven with a proprietary H-bridge drive cards. The motors from the specs I can find are .7 kw and 1500 RPM. The rapids and feeds on this machine are less than that of a Haas machine 1 year newer with AC brushless servos VS the brushed on this machine. Everything else is the same. I might be wrong here but I feel even a cheap servo drive will be better than what's in the machine now. I am not opposed to use what's in it now I but just do not have the know how to make it work. Buying Messa hardware is not an issue. I plan to do so as soon as I figure out what to get. If I changed out the drives the +- 10 volts is a no brainer. Just get a 7i77 and some add on IO boards if I need more than what's on the 7i77. Any help on this is appreciated.
The axxis are all driven with a proprietary H-bridge drive cards. The motors from the specs I can find are .7 kw and 1500 RPM. The rapids and feeds on this machine are less than that of a Haas machine 1 year newer with AC brushless servos VS the brushed on this machine. Everything else is the same. I might be wrong here but I feel even a cheap servo drive will be better than what's in the machine now. I am not opposed to use what's in it now I but just do not have the know how to make it work. Buying Messa hardware is not an issue. I plan to do so as soon as I figure out what to get. If I changed out the drives the +- 10 volts is a no brainer. Just get a 7i77 and some add on IO boards if I need more than what's on the 7i77. Any help on this is appreciated.
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