[CoAMarcus]

Because we have been modifying the G250 and G251 dimensions, the G540 has to be modified as well before we can order it in any sort of quantity. The testing has worked out very well, and we are currently waiting on PCBs and connectors. We are going over several aspects of the drive, and will be sending out our contest winner drives next week.

The latest iteration of the G250 and G251 will have their PCB gerbers sent out very soon, wholly dependent upon a quality board house getting the boards to us in a timely manner. We are dying to get our machines running these, and getting them out the door. The G540 comes next, but because it utilizes four of the G250s, we have to get them finalized before we can do anything with the G540 design.

-Marcus Freimanis

[Mariss Freimanis]

To add to what Marcus wrote:

1) The G250/G251 now also includes Automatic Standby Current. The phase current folds back to 70% of set value one second after the last step pulse. This cuts motor resistive heating and drive heating 50%.

2) The Current Set resistor is now a linear function of current; 1K equals 1A. You want 3.3A, you use a 3.3K resistor, you want 1.2A, you use a 1.2K resistor, etc.

3) The final board dimensions are 1.325" by 1.675" and are the same for both the G250 and the G251.

4) The G250/G251 had bloated $1.50 over it's budget. We had to get very clever with the circuit to preserve and even add features (1, 2) while putting the design on a strict diet. That involved a major redesign and I'm happy to say it has been successful.

We have been running the test production drives with no heatsinking whatsoever at 3.5A and 50VDC; the power MOSFETs get warm but not hot. To summarize:

CPLD based 10-microstep drive.
15VDC to 50VDC supply voltage.
0 to 3.5A motor phase current.
Mid-band resonance compensation.
Microstep to Full-step morphing at higher speeds.
Automatic Stanby Current.
Silent synchronous clocked design; no hissing, squealing, grunting or whistling. Ever.
Trimpot Adjust for low-speed smoothness.
Premium 4-layer printed circuit board.
NEMA-23 motor speeds tested to 10,000 RPM.
Very small size: 1/3 the size of a credit card.
Very efficient, very low drive heating.
Survives motor disconnect while powered.
All surface mount component (0603) design.
$29 for the G250 in large quantities, a little more for the G251.

Mariss

[alipavsky]

To add to what Marcus wrote:

$29 for the G250 in large quantities, a little more for the G251.

Mariss

Have you decided on pricing for mere-mortal quantities?

- Andrey -

[wolfdagon]

Wasn't thinking about the G250/251 modifications holding up the G540, although I should have. All of the changes sound great. Can't wait till it's all complete.

Kenith

[lagfish]

These drives are the last major component my mill needs. Can't wait!

[twit_biddler]

I'm just getting into CNC and will be placing an order for 3 G251's as soon as their available but...

What is the smallest recommended stepper motor the G250s can drive? I'm about to place an order for some 14V/400ma Bipolar drives but will hold off until I get an answer -- I don't need a lot of horsepower for my current setup.

Currently I'm trying out MC3479's driving 20yr old steppers with a PIC18f1330
Thanks

[twit_biddler]

Looks like post #562 answered my question (0-3.5A drive current).

While waiting for the G250s and the G540 boards to become available I guess I'll have to be happy with the MC3479s @ 1000 steps/sec.

[Crevice Reamer]

What SUPER products! My next mill will use the G540.

CR.

[skmetal7]

To add to what Marcus wrote:

1) The G250/G251 now also includes Automatic Standby Current. The phase current folds back to 70% of set value one second after the last step pulse. This cuts motor resistive heating and drive heating 50%.

2) The Current Set resistor is now a linear function of current; 1K equals 1A. You want 3.3A, you use a 3.3K resistor, you want 1.2A, you use a 1.2K resistor, etc.

3) The final board dimensions are 1.325" by 1.675" and are the same for both the G250 and the G251.

4) The G250/G251 had bloated $1.50 over it's budget. We had to get very clever with the circuit to preserve and even add features (1, 2) while putting the design on a strict diet. That involved a major redesign and I'm happy to say it has been successful.

We have been running the test production drives with no heatsinking whatsoever at 3.5A and 50VDC; the power MOSFETs get warm but not hot. To summarize:

CPLD based 10-microstep drive.
15VDC to 50VDC supply voltage.
0 to 3.5A motor phase current.
Mid-band resonance compensation.
Microstep to Full-step morphing at higher speeds.
Automatic Stanby Current.
Silent synchronous clocked design; no hissing, squealing, grunting or whistling. Ever.
Trimpot Adjust for low-speed smoothness.
Premium 4-layer printed circuit board.
NEMA-23 motor speeds tested to 10,000 RPM.
Very small size: 1/3 the size of a credit card.
Very efficient, very low drive heating.
Survives motor disconnect while powered.
All surface mount component (0603) design.
$29 for the G250 in large quantities, a little more for the G251.

Mariss

since it was a "major redesign," did you have to scrap all the boards from your first order?

$1.50 over budget? :/ what does that mean for us?

[Mariss Freimanis]

The first order was for a test run of 120 G250-REV4s and 120 G251-REV4s. These work very nicely as was expected. The first major board order (1200 G250-REV5 and 1200 G251-REV5) was let out for fabrication today. We will see these bare boards in 3 weeks. These include the auto-standby, new current set resistor interface and the in-budget circuit modifications.

"Over-budget" means the drive had become more expensive to build than originally planned. Cost overruns if you like. Like all businesses, our product end-user price is cost times an obscene profit multiplier. Bringing the drive budget (cost of manufacture) back into line means we will be able to meet the promised end-user price. This was very difficult to do and I'm proud of the accomplishment.

Let me give an example of some of the stuff involved; the technical types may appreciate this:

A CPLD requires 1.8VDC and 3.3VDC power supply voltages. The REV4 uses LP2985 SOT-23 regulators for the voltages at $0.32 each, $0.64 total. The REV4 uses an LM358 SOIC-8 dual op-amp at $0.12. An LM324 SOIC-14 quad op-amp also costs $0.12. That means the extra 2 op-amps are free but the package is 75% bigger.

One of the extra op-amps gets used as a 3.3VDC regulator. The other is used for auto current standby.

The power indicator is a 650nm red LED. It has a forward voltage drop of 1.8VDC at 4 mA. The CPLD 1.8VDC supply current is only 160uA. The LED gets temperature compensated and serves double-duty as a power indicator and a 1.8VDC shunt regulator for the CPLD. It's just like the peanut truck colliding with the chocolate truck; instant M&Ms.:-)

That alone took $0.64 out of the design while adding the auto standby current reduction. The other $0.96 came from similar design optimizations which scraped away a $1.50 from the design.

Mariss

[Crevice Reamer]

Elegantly done, Mariss! You da MAN!

CR.

[.xXACEXx.]

i gotta say it again....mariss and the rest at gecko drive ,..well done! nice way to try and save us.. the end user... from the extra cost of parts and well designed such a great understanding of electricity and ways to make it do your bidding so to speak..still i wish i could build stuff like that.... but i'll settle for buying it, all the same in the end...well better to buy it actually,instead of build it ,no one has ever seen my electrical work..

[jalessi]

Bragging about the 120 quantity orders,

What about "All the guys on the cnczone forum"


brag (brg)
v. bragged, brag·ging, brags
v.intr.
To talk boastfully. See Synonyms at boast1.
v.tr.
To assert boastfully.
n.
1. A boast.
2. Arrogant or boastful speech or manner.
3. Something boasted of.
4. A braggart; a boaster.
5. Games A card game similar to poker.
adj. brag·ger, brag·gest
Exceptionally fine.

--------------------------------------------------------------------------------

[Middle English braggen, from brag, ostentatious.]

--------------------------------------------------------------------------------

bragger n.

[twit_biddler]

Mariss, Is there any possibility of preordering? If so PM me and I'll send the cash.

If preordering is an accounting nightmare how about a new CNCZone only contest. Only the first 35* requests for preorders of (3) G250s will be allowed to CNCZone subscribers.

Just a thought.
Twit

*One must not forget prior contest winners are anxiously awaiting their drives.

[Jojje Bergan]

I can wait for the REV5 version.

[Ch_Irawan]

120 mean a 40 x 50 cm panel, that is my best guess...

I would love to have some of unused rev4 on my prize package :cheers:.

-ichan

[Mariss Freimanis]

Huh????

Mariss

Bragging about the 120 quantity orders,

What about "All the guys on the cnczone forum"


brag (brg)
v. bragged, brag·ging, brags
v.intr.
To talk boastfully. See Synonyms at boast1.
v.tr.
To assert boastfully.
n.
1. A boast.
2. Arrogant or boastful speech or manner.
3. Something boasted of.
4. A braggart; a boaster.
5. Games A card game similar to poker.
adj. brag·ger, brag·gest
Exceptionally fine.

--------------------------------------------------------------------------------

[Middle English braggen, from brag, ostentatious.]

--------------------------------------------------------------------------------

bragger n.

[Kipper]

^^ lol These look great!

[Xerxes]

Mariss, Marcus,

I looked G540 schematics and couple of things came into my mind:
-Wouldn't it be handy to have general purpose input pins routed to DB9 connectors? That way you can run limit switch signal in same cable with motor. Less cables & connectors needed.
-Don't DB25 pins 11,12,13,15 need pull-up resistors?

[CoAMarcus]

Mariss, Is there any possibility of preordering? If so PM me and I'll send the cash.

If preordering is an accounting nightmare how about a new CNCZone only contest. Only the first 35* requests for preorders of (3) G250s will be allowed to CNCZone subscribers.

Just a thought.
Twit

*One must not forget prior contest winners are anxiously awaiting their drives.

Twit,

We do not take preorders because the chances of losing the order that is already paid for is too high. We only take orders when we have product to ship.

There will be one more contest before these drives are released, and we will be running it some time in the coming weeks. Right now we are waiting on some connectors, and as soon as we have them we will ship the drives out to our contest winners. The connectors were supposed to be here Friday, so I will have to make some phone calls to see what is going on.

The drives should definitely ship this week to our contest winners, and I will post as soon as they are sent out.

-Marcus Freimanis