G250/G251 vs Msd542

[adpsm2003]

Hi, I can't decide what to buy to drive my fl60sth86 stepper motors.
Any pros and cons for these drivers, which one is a better choice?.
fl60sth86-4.2a/2.73v bipolar parallel
Thank you in advance.

[David Campbell]

Originally Posted by adpsm2003 Hi, I can't decide what to buy to drive my fl60sth86 stepper motors. Any pros and cons for these drivers, which one is a better choice?. fl60sth86-4.2a/2.73v bipolar parallel Thank you in advance.

The things that I can spot:
Microstepping resolution:
G250 is hard locked to 10 microsteps
MSD542 can be varied between 2 to 128 microsteps
Advantage: Neither - beyond 10 microsteps you are at the mercy of the motor linearity, there is really nothing to gain beyond that point.

Input frequency: G250 is 200kHz, MSD542 is 400kHz
Advantage: Neither - at 200kHz with x10 microstepping is 6000 RPM, only very small steppers will keep spinning at that speed.

Current control: MSD542 supports slow decay mode, Geckos don't
Advantage: MSD542 below 200 RPM & high supply voltages (cooler stepper motors)

Electronic resonance dampening: Supported by Geckos only
Advantage: G250 between 240 to 400 RPM (varies with systems)
If you have a system with minimal mechanical friction then the resonance issues are going to be more of a problem than a hot stepper motor.

David Campbell

[audioandy1762]

Don't forget about the excellent backup from Gecko, if you run into trouble Marris will help out even repair your damaged units for free which in the case of any repair makes them a cheap drive.

Just my 2 cents

Andy

[Crevice Reamer]

Those fl60sth86 are 83V motors. You will want to use the maximum 48-50V Power supply and wire them Bipolar Parallel. I recommend the G250 drives, which will run these motors well, but in the much less expensive G540 package.

If you were buying them separate, you would get the G251s for about $210 for three.

Next, you would have to spend about $80 for a breakout board. (Which the G250 already has.) You are at this point spending $290--Just $10 less than the G540. Add the cost of cable connectors, (Which come WITH the G540) and you've spent more.

So for roughly the same price you have given up all of the magnificent G540 features like Vampire unkillability, Idle current limiting, 10 micro step to full step morphing, and about 12 more. Plus, there's a spare drive in the G540 that can also be used for a future fourth axis. (Another $70 value)

The G540 has its own 5V logic PSU built in, but for the G251s you will have to buy one--another $20.

If you plan on CNC controlling your spindle speed--That will cost at least an additional $40 for what comes free in the G540.

Get the plug & play G540!

http://geckodrive.com/product.aspx?c=3&i=14469

You will also need some other stuff:

The $60 KL-350-48 power supply will be adequate for as many as 4 of your motors:

http://kelinginc.net/SwitchingPowerSupply.html

You can use THIS wire for motor cables and home/limit switches. Ground the drain wire ONLY at the driver end.

http://cgi.ebay.com/Servo-Motor-Wire...3286.m20.l1116

You won't need any db9 motor connectors with the G540, as they come WITH it. The G540 also has circuitry for simple spindle speed control and outputs for dc relays to turn coolant pump on or off. These relays are good and cheap:

http://www.surpluscenter.com/item.as...tname=electric

You WILL need 2.8K 1/4 watt current limiting resistors, one for each motor. You can get them here:

http://www.digikey.com/

If you don't already HAVE them, these are excellent home switches:

http://cgi.ebay.com/6-CNC-LIMIT-SWIT...742.m153.l1262

They are NO, so only for home switches. Limit switches need to be NC. the whole set of 6 switches costs less than ONE switch would cost at Radio Shack.

These limits from Enco will do fine and only cost $2.34 each. Now you know what a deal the home switches are.

http://www.use-enco.com/CGI/INSRIT?P...PMPXNO=7908441

You will also need an estop switch. This one from Keling only costs 10 bucks and works fine:

http://kelinginc.net/CNCPackage.html

CR.

[adpsm2003]

Thank you to all of you for help,i bought g540.

[Crevice Reamer]

Excellent! Congratulations for an astute purchase decision.

CR.

[Degrom]

Originally Posted by Crevice Reamer So for roughly the same price you have given up all of the magnificent G540 features like Vampire unkillability, Idle current limiting, 10 micro step to full step morphing, and about 12 more. Plus, there's a spare drive in the G540 that can also be used for a future fourth axis. (Another $70 value)

It all looks very good. I am building a system that will need 4 stepper drivers. The only concern I have is the G540 design where the XYZ and A drives are not the same driver boards. This is a pain cause I will have to stock 2 spare boards...

[Mariss Freimanis]

All G540s are now REV4. All the drives in the REV4 are identical G250s (x, y, z and a axis).

Mariss

[Degrom]

Originally Posted by Mariss Freimanis All G540s are now REV4. All the drives in the REV4 are identical G250s (x, y, z and a axis). Mariss

That is just brilliant news...

Thanks.

[Mariss Freimanis]

The G250 drives inside the G540 use a programmable controller IC (a Xilinx CoolRunnerII CPLD). This means if necessary, a G250 can be reprogrammed at any time in the future.

G540 REV4 motherboards have a slide-switch immediately next to terminal 12 on the motherboard. All earlier revisions don't.

If you have an earlier revision G540 and you are not comfortable with non-identical drives, you can return your G540 for a REV4 upgrade. We will replace the motherboard with a REV4 and reprogram the G250s inside to standard off the shelf G250 firmware. The G540 REV4 user's manual applies after the upgrade. This is at no-charge of course.

This is being done to show respect for the early adapters of our new products.

Mariss

[phomann]

Originally Posted by Mariss Freimanis The G250 drives inside the G540 use a programmable controller IC (a Xilinx CoolRunnerII CPLD). This means if necessary, a G250 can be reprogrammed at any time in the future. G540 REV4 motherboards have a slide-switch immediately next to terminal 12 on the motherboard. All earlier revisions don't. If you have an earlier revision G540 and you are not comfortable with non-identical drives, you can return your G540 for a REV4 upgrade. We will replace the motherboard with a REV4 and reprogram the G250s inside to standard off the shelf G250 firmware. The G540 REV4 user's manual applies after the upgrade. This is at no-charge of course. This is being done to show respect for the early adapters of our new products. Mariss

Hi Mariss,

I think I have a mix of G250 drives. I'd like to send the non-conforming ones back for reprogramming. I notice that there is a dab of silver paint on the CPLD. Can I tell from that which is which?

Cheers,

Peter.

[Mariss Freimanis]

The dab of silver paint meant the CPLD was programmed and the drive passed all tests. We don't use that method anymore because yields exceed 98% now.

Mariss