G215 drive

[Mariss Freimanis]

I know I haven't posted for quite a while. The reason is I have been completely occupied developing what I think are some very interesting new designs.

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.

Mariss

[judleroy]

Do you ever get tired of being called a genius?Lol
judleroy

[Mariss Freimanis]

Not a genius certainly by my definition in any way. I know way too many people who are smarter than I am.

Rather I'm a guy that has fun running down all those pretty pictures of ideas that appear in my mind. I'm also a lucky guy because I know most people smarter or not than me don't get to see those pictures in their minds.

It's nothing I have earned to have so it's nothing I have to take pride of accomplishment in.

Mariss

[CoAMarcus]

For those wondering about how the VCO would be used, you can watch the video below. The applications this could be used for would be automated cutters, conveyors, etc.

http://www.youtube.com/watch?v=gsDMpgwICrU]Geckodrive G215 VCO Demonstration HD - YouTube

[ger21]

The G215 will become available in late September.

Just in time for the customer appreciation sale?

[CarveOne]

Oh well, it looks like it's time to order four new G215 Drives and plan a new machine project around them.

CarveOne

[dmauch]

I have a suggestion . As your design currently stands why not add a dip switch to regulate the number of cycles.
1. On OFF OFF OFF continuous cycles
2 On On Off off 1 cycle and and stop
3. ON ON ON off 2 cycles " "
4 On On On On 3 cycles
5 Off on on on 4 cycles
6 Off off on on 5 cycles and stop
etc etc etc

And with all the remaining cycles there would be plenty of cycles before it stopped.
The other thing would be to allow for a signal from either limit switch to activate another driver to do a second operation When the sub routine is complete the sub roitine would signal the primary driever to resume.

Dan Mauch
Camtronics, inc. -- CNC with Dan Mauch
Gecko products, kits, stepper motors and custom CNC

I know I haven't posted for quite a while. The reason is I have been completely occupied developing what I think are some very interesting new designs.

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.

Mariss

[Mariss Freimanis]

Oh well, it looks like it's time to order four new G215 Drives and plan a new machine project around them.

CarveOne

One reason might be the G215 can work as an axis power feed all by itself. No computer needed.

Mariss

[H500]

Clever! I especially line the autonomous feature.

Have you considered using a DSP rather than an FPGA?

[Mariss Freimanis]

H500,

It's mixing apples and oranges in my opinion. A DSP is just an MCU with some specialized instructions to facilitate signal processing. As an MCU, it still is a sequential machine with all the drawbacks such as loop timing issues and a susceptibility to crashing.

An FPGA is a parallel machine and as such, it doesn't contain a program counter, instructions or looping (unless you program it to be an MCU). It does all its tasks simultaneously. This bests fits the requirements of a motor drive.

Mariss

[dmauch]

I can see how a power feed would be used in a one cycle mode on say a milling machine. After each cycle the operator would have to increase the feed if needed where more than one cut/pass was needed. That is where my suggestions of an output to a second 215 would be very helpfull. In the case of my suggestion after the first 1/2 cycle or full cycle the 251 would signal the second 215 to perform one cycle which would be the depth of the next cut. After the second 215 performed it operation then it wouild signal the first 215 for its operations and this would repeat for as many cycles as desired/needed. You would need to automate the second axis of course.
In the case of a surface grinder. You would need the Y axis to be indexed after every cycle and that is where two 215 working to gether would be great.
What do you think of linking more than 1 g15?

Dan Mauch
Camtronics, inc. -- CNC with Dan Mauch
kits, assembled and custom CNC using Gecko Products.
stepper and servo motors.

One reason might be the G215 can work as an axis power feed all by itself. No computer needed.

Mariss

[ger21]

It would be really cool if you could connect external switches to change modes.

I'm thinking of being able to use a drive like this for a rotary axis. One mode would be controlled with step and direction signals from Mach3.
Then, flip a switch to make it act like a standard motor, with a pot controlling the speed, for continuous rotation.