[bokito]

I just want to know one thing, because i can not find in the specification:
is morphing from a microstepping to full-stepping is included option in G215 drive, for me is very needed option
keep the great work...

[Mariss Freimanis]

All of our drives have microstep to full-step morphing. I guess that's why I didn't mention it.

Mariss

[Dave3891]

Will the drive have linear acceleration or S curve?

Dave

[Mariss Freimanis]

Both in a sense and everything in between. The GM215 uses an adaptive 512 max sample FIR filter (boxcar filter) for the step pulse velocity that is variable from 1 to 512 samples. In effect the user can continuously vary the FIR filter from linear acceleration to a strong S curve with these 512 available settings.

Mariss

[Dave3891]

Would the user set this up in the pic firmware?

Dave

[Mariss Freimanis]

All settings are made via a UART interface to/from the GM215. Hyperterminal or RealTerm can be used in a pinch but you will probably want to use the GeckoMotion.exe GUI being developed by a company we hired to develop it.

The GM215 will be available with two connector options:

1) A 12-position 5mm modular connector block we have used in the past. UART communication using this connector uses the COMMON. STEP and FAULT opto-isolators. In the motion control mode these become GND, Rx and Tx (term. 10, 9 and 11 respectively). A $20 "smart cable" from DigiKey plugs into a PC USB port and the other end connects to the GM215.

2) Uses a 6 position MTA-156 connector for power supply and motor phase wires and a 12-position MTA-100 connector for the signal interface.

This connector option has 6 more pins than what's in (1). This allows for an RS-485 communications interface and allows for 3 optoisolated outputs instead of one. In (1), the only output and one input are tied-up with UART communications. This leaves only 2 inputs as the available I/O.

The MTA connector option allows 6 I/O connections (3 in, 3 out) to be always available.

Mariss

[Dave3891]

Can you give an example of setting up a custom S curve acceleration via UART commands?

Thanks
Dave

[Mariss Freimanis]

No, I can't at this point. Presently we are in qualifying each GM215 instruction as passing or needing debugging. This is an intense phase of qualifying the firmware and I cannot step out of the queue on this processes. Please be patient until the firmware qualification is completed.

Mariss

[Dave3891]

Are the 512 acceleration points some kind of look up table for the accel values?


Dave

[Mariss Freimanis]

No. The GM215 frequency synthesizes 65,535 evenly spaced step pulse frequencies. These frequency commands are updated 1,000 times a second and sent to the motor drive section of the FPGA.

Example: Let's say the ACEL rate is set to '10' and you begin acceleration from zero velocity. The velocity commands sent every millisecond would be 10, 20, 30, 40, 50, 60, 70, etc. This gives a linear acceleration ramp.

Now let's say they are sent to an empty 10 sample boxcar filter instead: The first command is '10' which is sampled by the filter while the remaining 9 are zero. The average of one '10' and nine '0s' is 1.

The next velocity command is 20. The filter now contains 20, 10, and eight zeros which average to 3. (20+10 / 10).

(10+0+0+0+0+0+0+0+0+0) / 10 = 1
(20+10+0+0+0+0+0+0+0+0) / 10 = 3
(30+20+10+0+0+0+0+0+0+0) / 10 = 6
(40+30+20+10+0+0+0+0+0+0) / 10 = 10
(50+40+30+20+10+0+0+0+0+0) / 10 = 15
(60+50+40+30+20+10+0+0+0+0) / 10 = 21
(70+60+50+40+30+20+10+0+0+0) / 10 = 28

Now let's say you stop accelerating. The filter then continues as:

(70+70+60+50+40+30+20+10+0+0) / 10 = 35
(70+70+70+60+50+40+30+20+10+0) / 10 = 42
(70+70+70+70+60+50+40+30+20+10) / 10 = 49
(70+70+70+70+70+60+50+40+30+20) / 10 = 55
(70+70+70+70+70+70+60+50+40+30) / 10 = 60
(70+70+70+70+70+70+70+60+50+40) / 10 = 64
(70+70+70+70+70+70+70+70+60+50) / 10 = 67
(70+70+70+70+70+70+70+70+70+60) / 10 = 69
(70+70+70+70+70+70+70+70+70+70) / 10 = 70

After this, nothing changes unless there is an acceleration or deceleration again.

The filtered velocity commands have an S curve output if the filter input is a ramp. The S curve lasts for n/2 (10/2) sample periods at the start and another n/2 sample periods at the end. The greater sample number, the longer the duration of the S curve. For the GM215, this number can range from 1 to 512.

Mariss

[Dave3891]

Looks like a very customizable way to have the acceleration.

Are the drives able to interpolate with each other with different acceleration settings?



Dave

[Dave3891]

Have you looked at adding a stall detect feature that would issue a e-stop or error signal like the one described on this web site?

Back-EMF method detects stepper-motor stall : EDN Europe

It doesn't use an encoder, only back EMF to detect the stall.


Dave

[dmauch]

When can we start playing with them? :cheers:

Dan Mauch
Camtronics Inc

No. The GM215 frequency synthesizes 65,535 evenly spaced step pulse frequencies. These frequency commands are updated 1,000 times a second and sent to the motor drive section of the FPGA.

Example: Let's say the ACEL rate is set to '10' and you begin acceleration from zero velocity. The velocity commands sent every millisecond would be 10, 20, 30, 40, 50, 60, 70, etc. This gives a linear acceleration ramp.

Now let's say they are sent to an empty 10 sample boxcar filter instead: The first command is '10' which is sampled by the filter while the remaining 9 are zero. The average of one '10' and nine '0s' is 1.

The next velocity command is 20. The filter now contains 20, 10, and eight zeros which average to 3. (20+10 / 10).

(10+0+0+0+0+0+0+0+0+0) / 10 = 1
(20+10+0+0+0+0+0+0+0+0) / 10 = 3
(30+20+10+0+0+0+0+0+0+0) / 10 = 6
(40+30+20+10+0+0+0+0+0+0) / 10 = 10
(50+40+30+20+10+0+0+0+0+0) / 10 = 15
(60+50+40+30+20+10+0+0+0+0) / 10 = 21
(70+60+50+40+30+20+10+0+0+0) / 10 = 28

Now let's say you stop accelerating. The filter then continues as:

(70+70+60+50+40+30+20+10+0+0) / 10 = 35
(70+70+70+60+50+40+30+20+10+0) / 10 = 42
(70+70+70+70+60+50+40+30+20+10) / 10 = 49
(70+70+70+70+70+60+50+40+30+20) / 10 = 55
(70+70+70+70+70+70+60+50+40+30) / 10 = 60
(70+70+70+70+70+70+70+60+50+40) / 10 = 64
(70+70+70+70+70+70+70+70+60+50) / 10 = 67
(70+70+70+70+70+70+70+70+70+60) / 10 = 69
(70+70+70+70+70+70+70+70+70+70) / 10 = 70

After this, nothing changes unless there is an acceleration or deceleration again.

The filtered velocity commands have an S curve output if the filter input is a ramp. The S curve lasts for n/2 (10/2) sample periods at the start and another n/2 sample periods at the end. The greater sample number, the longer the duration of the S curve. For the GM215, this number can range from 1 to 512.

Mariss

[mklb]

I'm curious to see how the G215 will reference home position, and how you would "Call up" different stored programs.

I have several machines that run the same programs over and over. Maybe 8 to 12 different programs. If I can assemble 3 G215's on each machine, load in the different programs and just call them up as i needed. I would need to reference them at the start of the day, but other than that they could just run over and over and over.

Royce Bunnell
Pool Cues | Billiards and Pool Cues | OB Cues

[Mariss Freimanis]

Invoking the HOME command causes the GM215 to move towards the home switch at your chosen speed and rate of acceleration. Once on the home switch (switch closure), the G215 decelerates to a stop, reverses direction and moves off of the switch. The switch is polled every millisecond; once the switch shows 'open', the G215 stops the motor and clears its position register.

For an HM; command, the G215 then goes to the next command in the program.

For an HM 1234; command, the motor moves 1,234 increments of motion off of the limit switch and then clears its position register. This sets up a zero position that is offset from the home switch. It then goes to the next command in the program.

Mariss

[Mariss Freimanis]

Dan,

Not much longer. You will be playing with a set of 3 G215s beta units next week.

In the meantime, go to digikey.com and get yourself a USB to 3.3V UART smart cable (768-1015-ND) for $20, download RealTerminal (Terminal Software) for free and have Marcus send you the "GM215 preliminary users manual.pdf" and the necessary MTA-100 and MTA-156 mating headers for the G215.

That will be enough to get you started in trying out what the G215 can do.

We have 200 pre-production G215s built. They don't have the RS-485 interface nor the 65,536 command line non-volatile EEPROM stuffed. You will have to make do with the smaller 128 command line non-volatile EEPROM and interface the smart cable UART to the to the opto-isolated I/O (IN3=Rx, OUT1=Tx, 19.2kB, no parity, Rx/Tx only, 8-bit format).

Once the RS-485 interface and large EEPROM clears test, you can return them to be hardware and firmware updated.

If you feel really optimistic, get from digikey the USB to RS-485 smart cable (768-1042-ND). You may want to use it when the hardware gets upgraded.

I hope you will like the G215; being geeks, I and the two other engineers working on this project are practically rolling on the floor in ecstasy watching what the G215 can do.

Mariss

[mmcp42]

where can I get one?

[Bx3mE]

where can I get one?

It is listed on the UK Distributor site but out of stock....
Motion controller » Motion Controller » Stepper Motor Drives » Charter Controls

Any news?

[marzetti]

Interesting that it's being sold overseas yet it's not listed on the Gecko website.

[johnd]

Any update on the roll out of the 215?