ah, looks like this might be a duplicate... I'll put it in here as I'll never find it again otherwise! :)
Breakthrough 1: Total improvement of performance
2M880N adopts high performance DSP motor control chip, current control will be more precise if combined with space vector current control technique. Low frequency vibration of stepper motor will be much improved.
2M880N optimize motor power drive circuit, so even the drive current is raised 2A higher than 2M860, the temperature of drive stays almost the same, meanwhile the working noise is lower.
Subdivision accuracy is 3 times higher than 2M860, the maximum pulse input frequency is 400 KHz.
Breakthrough 2: 5 functions are newly added, easy to use
The five newly added functions such as alarm output, single/double pulse, motor parameter adaptation, phase memory and trial operation will bring wholly new use's experience.
The motor adaptation function could detect the motor it drives and allocate the most appropriate parameter to make sure the motor run in the best condition. Open collector alarm output, the output port could adapt with the most of PLCs. Host computer could monitor the drive working condition at any time which improves controllability of the whole equipment. Phase memory could assure stepper motor won't vibrate after power-off restart. Clients don't have to worry about unplanned outages anymore.
Motor parameter adaptation
Drive trial operation
Single/double control pulse input
Optocoupler isolation ERR fault signal output, the maximum current is 20 mA
16 mirco-step. Maxium is 256
Overvoltage, undervoltage, overheat, overcurrent alarm
All of this is well over my head so I'm greatful for the discussion about it.
I'm non the wiser, but I am much better informed! :-)
The 203's should be better than the PM752 as the PM752 does not use vector current control. Compare 203's to 2M880N and the latter will be better as Vector control > resonance damping
Edit: should have checked the 203's rating. They're quite similar, except the price!
Lets just leave it that I Know what I know regards Gecko's V's Pm752's and I'll reserve judgement on the 2m880N untill I've had actual hands on experience. . . Which I'm sure will happen at some point in the not too distant future.?
There is a new range of gecko drives on the way with all sorts of goodies, including vector drives. Marriss has just posted details about the first one over on the zone, which is a pretty conventional drive but with standalone functionality.
I'm more interested in the closed loop stepper driver, which is part of the new drive range.
The Following User Says Thank You to m_c For This Useful Post:
Thanks m_c, just had a read through that post from marriss, seems like there might well be another g540 in the pipeline? If I'm right that the G540 has 4x g250 or G251 in it(?) the New G215 might just drop in! I noted too that there is at least two versions of it;
"recent mods to the sense lines and the new trim pot location"
either way, if the new ones come out at the end of September, it might drop the price of the "old stock"enough to get me in the game!
Not sure how most of it affects my type of home brew machine. I can't think of a way I could use it other than Arduinocnc??? lol
Here's the post in question for those with an interest;
First off, in our future new products we leaving CPLDs behind and be will using FPGAs instead. For the non-technical types, CPLDs and FPGAs are programmable ICs that replace a boatload of discrete logic such as gates, counters, decoders and such which are necessary to build motor drives.
The difference between CPLDs and FPGAs is the size of the 'boatload'. A CPLD replaces about 20 discrete 7400 logic series ICs while an FPGA replaces over 200. Think of it as moving from a 500 square-foot studio apartment to a 5,000 square-foot luxury home.
That's what it feels like to an engineer; all the stuff that wouldn't fit in the apartment now fits in the home plus lot more things you'd always wanted to get. It's like you died and went to heaven.
The G215 is a step motor drive. It's like the G203 (lot's of protection circuitry), like the G201X (DIP-switch settable features) and like a G901X (a can't be fooled step pulse multiplier). All the goodness of the best of our drives all rolled into one.
That uses up only 1/3 of an FPGA.
The G215 has a MODE switch on it's internal 10-position DIP switch. When 'OFF', it's an ordinary step motor drive. When switched 'ON', it changes personality.
It becomes a motion controller with its own built-in step pulse generator. The STEP input becomes a CW limit switch input and the DIRECTION input becomes a CCW limit switch. Two trimpots set independent CW and CCW motor speeds. The DISABLE input becomes a RUN/STOP command. Another trimpot sets the accelerate/decelerate rate. It now performs the most common industrial applications for step motors; run between two limit switches at two different digitally set speeds with the option of stopping and restarting motor motion between the limit switches. The FAULT output indicates when the motor actually stops after deceleration. All motion is digitally generated with digital accuracy.
This uses up another 1/3 of the FPGA.
The remaining 1/3 of the FPGA is used for several purposes:
1) In a perfect world, step motors would be perfect and need only sine and cosine currents to move them. In the real world, step motors have non-linear characteristics which requires a compensating distortion of the sine and cosine currents that drive them.
You may have noticed this if you use step motors optimized for high holding torque. They have pronounced vibration at low speeds even when driven with perfect sine-cosine drives.
These motors need to be driven with a drive that has a compensating distortion of its current profile.
Now imagine a drive that has a family of 8 current profiles stored in it ranging from undistorted to significantly distorted. The profiles are arranged in FLASH memory in the G215 in order. The best profile for your motor is selected by turning a trimpot; you turn the trimpot until your motor vibration goes away. Again, all digital. The trimpot goes to an Analog to Digital converter that selects the best profile of your choice.
2) There is a whole bunch of reasons why a drive might not work.
A miss-wired motor, a motor winding that isn't connected, a short circuit, bad STEP and DIRECTION input signal quality or polarity, insufficient or excessive power supply voltage, drive overheating, etc and etc.
Our existing protected drives light up a FAULT indicator for some of these problems or give no indication at all for others.
The G215 will use a 16 error 'blink code' to identify why your motor isn't running. The G215 has two LEDs; a red and a green one. If everything is OK, the green LED will be a solid green.
If there is a problem like motor winding 'A' not connected, the LEDs will blink 'RED, RED, RED, GREEN, pause, RED, RED, RED, GREEN' pause, and so on. The code for that sequence will be listed in the manual as "Winding 'A' not connected". This will make trouble-shooting much easier.
The G215 will become available in late September. It will be the first of our new line of FPGA drives. Many other new products will follow in the next 6 moths based on this switch to FPGA logic drives.
Cost? Equal to or less than our current drives. Why? because so much functionality now moves inside the FPGA and no longer requires external analog circuitry.
Last edited by mocha; 20-09-2011 at 03:16 PM. Reason: typos
To save everyone finding the relevant thread:
Interesting that he makes using an FPGA sound like it's something special/unique to use, or at least that's how it reads to me. PM752, and no doubt many others in the range, also use FPGAs as it's just easier. I'd use one if I thought I had a chance of soldering BGA's!
The original comparison was 540 vs 2M880N - there the latter surely wins due to the better control algorithm and ratings. 2M880N vs 203V is less clear cut ... until I see a fair test done between the two I would go for the 2M880N as it seems to still have the better control algorithm, and it's cheaper? (Correct me if I'm wrong, not sure how much the 203V is?). I'd happily do the comparison properly, i.e. at different feedrates and accelaration with a few different motors plus record waveforms with oscilloscope, but currently I own neither drive.
You have to admire Marriss for the both way he's so transparent and gives clear no bull shit information and how he runs his business.
How meny large company directors would take the time to post and directly chat on a forum.? . . Not too meny mi thinks.!!
The warranty and service Gecko gives is unrivelled in my experience, even if it's your own stupid fault you've fry'd the drive (Which it often is) I've seen them replace units FOC. . . . Now thats service.!! . . . .Try that with a chinese manufacturer or even UK distributor and watch them :lol: you out the door.:exclaim:
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