[LeeWay]

They are rated at 3.5 amps, so you could put the 3.5 K resistor in place and up the amps that way.
I am just speculating, but I think if you overclocked these like in a CPU, you would have the warranty voided.
I don't think that means these won't do that. They might. If you had a nice CPU cooler on each drive.
That would get you right up there in 201 territory though. If I was going to run over 3.5 amps, I would use a bigger drive. I like having the warranty.

You may not even be able to see the extra .7 amps worth of performance to make it even worth the risk of squashing a baby gecko.

[Mariss Freimanis]

You really should use a 3.5K resistor (3.49K 1% standard value). Here's why:

1) The G250/G251 will not put out more than 3.5A no matter what size resistor is used.

2) Warning! Technical Stuff: The G250/G251 uses 0.056 Ohm, 0.5W current sense resistors. Why 0.5W? Because they are cheap is why. The resistors cost $0.04 each, the 2W current sense resistors in the G203V cost $0.35 each.

The G250/G251 standby current (motor stopped current) is 71% of the set current (motor turning current). If the current set resistor is more than 3.5K, the standby current is 100% of set current. It is a design artifact (design compromise) of the drive circuit.

The RMS current at 3.5A is 2.47A for a turning motor. Current sense resistor heating is 0.343W (0.056 Ohms * 2.47A^2), a derating I'm comfortable with. Now, let's say you bring the motor to a stop and have the misfortune of stopping the motor at the peak of the sine or cosine current (sin = 90 or cos = 0 degrees). 3.5A thru a 0.056 Ohm resistor gives 0.686W of heat in a 0.5W rated resistor.

The resistors will survive (tested and confirmed) but I'm not comfortable about busting specs on any rating. This is where standby current comes in. 71% of 3.5A is that 2.47A again. Then the resistors are happy and I'm happy. However, no current set resistor, no standby current reduction. Please always use 3.5K or less current set resistors.:-)

Mariss

[CROSSHATCH]

Mariss has been helping me, but I have been doing what everyone has told me and can't get the 540 out of fault!

http://www.cnczone.com/forums/showthread.php?t=65225

Refer to the last two pages for my problem. I seem to have it all right but nothing is working properly. Still have that awesome RED fault light on!


I was also like 2 days short of the Rev3 version with the switch for the charge-pump. HOWEVER! When I did buy mine I got it on Wednesday the 17th. I had not touched it or anything, GECKO sent me a brand new one I think by this Monday: 22nd. There was a recall on the one I was sent the first time.

Is it possible that Gecko maybe sent me a new version with the switch inside for the charge pump? I just thought about that....Unless they sent me the same version.....



I need to get my machine working so I can start making panel cut outs on my electrical enclosure and get back to business work.




I had to deal with the same things when I got my XYLOTEX board, some of you may remember that whole problem, I ended up buying a new computer and everything....



Please guys Shed some light, hopefully GREEN lol


-Jason

[CROSSHATCH]

I guess at this point since I have seemed to already done everything, BIOS, enable/disable the charge-pump (just to see if it works) is to check out a new parallel cable. Maybe mine is bad?...Maybe I'll head to Rat Shack tomorrow.


Bummer


-Jason

[ger21]

Do you have a meter that you can check the cable with. If it's not the cable, my guess is your not getting the charge pump working.

[LeeWay]

I haven't tried EMC, but is there a switch inside it to enable and disable the charge pump?

[cadcamslawek]

Hi
On my servo system to get charge pump working had chenge settings in Mach3 go to:
config
general config...
set charge pump to 5khz-laser stent by (CHECK BOTTON)

This works for my setup.
Slawek

[CROSSHATCH]

EMC2 is a little different, I can go into my Hal file and change it through there. From what I have heard though, you can just go into the Spetconf and change it with a mouse click, which is true. I have everything in Stepconf set-up as if it would be my system.

Pin1 is for E-Stop (Which is not plugged in, just jumpered)
Pin17- Coolant Flood output
Pin16- Chargepump
Pin15 unused
And all the other pins, set accordingly.

I do not have a meter to check my cable.

I do however find it hard to believe it's the cable.


I don't know if I have the newer version the 540 because I ordered it before they were shipping the 540 with the switch, however....there was a recall and a new one was sent to me after they started shipping the NEW 540's. So maybe there is a switch inside. I guess I need to open it up.



-Jason

[LeeWay]

You don't have a multimeter?

$3 at HF.

[CROSSHATCH]

OMG! Problem solved!

Open the 540 case, saw the switch. Boom! Installed my E-Stop and works perfectly!


I am getting unbelievably scary results! I did not think it would work this fast on my machine. It's zipping on the Taig! I lowered the Velocity down to 20.00 IPM.


I accidentally think I was hitting about 100+ IPm on the machine.... I jogged it though..... Not doing that again!




Ok one more Question! In the manual for the CURRENT SET RESISTORS: It says that a 3.3 A per phase motor requires a 3.3K resistor, 1.5 A per phase requires a 1.5K resistor.

If i'm running my motors @ Bipolar (Parallel) which is 4.2 Amps Per Phase do i need a 4.2K resistor or a 3.5K resistor because the 540 will only output 3.5 Amps per axis, so should I get a 3.5 K resistor? And if so, just to clarify, that RESISTOR gets soldered between 1 and 5 on the DB9 connectors correct?




I only ran them for a few minutes, jogging back and forth. The motors were warm (maybe cause I accidentally was doing like 100+ Ipm for a second or two) and the 540 was luke-warm. Wouldn't hurt to install a fan on the case now would it? It can't hurt but could be useful.




-Jason

[ger21]

Get 3.5K resistors. If you have plenty of power, maybe even 3.3K, which might keep things a little cooler.

[CROSSHATCH]

Ger21- It really does seem like I have a lot of power, A LOT!


I'll head to Radioshack and pick up a 3.3K 1/2watt pack of 5! Of yea Again, that gets soldered between 1 and 5 on the DB9 connectors? Ok I thought so



-Jason

[Jay C]

If you find any at RS let me know.

[LeeWay]

They sell an assortment of like 500 with all different sizes. This is what I use for all my resistor needs so far. I had to go through and mark all the different sizes, but that wasn't too difficult. You can chain resistors together to get the needed size too, so it doesn't have to be the exact size. I just twist them up and and shrink wrap them. That makes a nice little resistor package.

[CROSSHATCH]

Yea, they have large pack of 100 with multiple ones. I kinda just ordered some from mouser, but Maybe I should have gotten the pack from Radioshack because it cost about 9 dollars....for 10. Maybe I can cancel it...


-Jason

[jalessi]

Resistor Deals

$1.00 per hundred plus $2.00 shipping.


http://tinyurl.com/4h4mwq

[CROSSHATCH]

I don't have E-bay account! I'm banned!


I guess ratshack will have to do, they actually have some large switches too which is good.


I still don't get why I need a 3.3 K resistor if I'm using a 4.2 Amp motor....Considering that the 540 limits each axis to 3.5 anyway.




-Jason

[ger21]

I still don't get why I need a 3.3 K resistor if I'm using a 4.2 Amp motor....Considering that the 540 limits each axis to 3.5 anyway.




-Jason

Back up 15 posts and read #1702.

[wolfdagon]

Marris explained the reason for this in post #1702.

[JerkyBoy]

Speed Custom,

Why are you banned?

Are you a engineer?

Can you help me will my Taig?

Jerkyboy