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Current Hi/Lo setting?
« on: August 02, 2011, 04:40:33 PM »
I'm confused with the Current Hi/Lo setting in the Output Sign as configuration.  I think I'm right in saying that it can limit current to the motors until actually required, which assists in keeping them cool?

The bit I'm confused about is what pin do I assign it to and where does it go!  Does it only relate to driver boards that have a specific function to reduce the motor's current and have an appropriate pin?

Apologies if it's a stupid question!

Keith

Offline RICH

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Re: Current Hi/Lo setting?
« Reply #1 on: August 02, 2011, 05:03:44 PM »
Keith,
What drives are you using? Post info on them.

Quote
can limit current to the motors until actually required, which assists in keeping them cool?
No, usually done with a switch / resistor  on the drive .... but if you post info about your drives surely someone will take a look to better help you out.
RICH
Re: Current Hi/Lo setting?
« Reply #2 on: August 02, 2011, 05:28:25 PM »
Hi Rich,

Thanks for that.  I'm only using a very cheap and probably low quality 4 axis drive board, based on the TB6560.  Whilst it's at the lowest end of the quality scale, it's perfect in getting my
new machine 'up and running'.

http://reprap.org/wiki/4_Axis_TB6560_CNC_Stepper_Motor_Driver_Board_Controller

Keith

Offline RICH

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Re: Current Hi/Lo setting?
« Reply #3 on: August 02, 2011, 05:42:42 PM »
You set the current for each axis using the dip switches on the board and the max current setting is 3A per axis.
What current setting you use depends on the motor rating and  how it is wired.

RICH

Offline Tweakie.CNC

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Re: Current Hi/Lo setting?
« Reply #4 on: August 03, 2011, 02:40:53 AM »
Keith,

You may find the info presented here of interest  http://www.savebase.com/infobase/downloads/TB6560/TB6560_4Axis_Driver.doc

(the RepRap is wired differently to any CNC router and so has different pin assignments)

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Current Hi/Lo setting?
« Reply #5 on: May 05, 2014, 03:19:10 AM »
Hi Rich et al
Quote
You set the current for each axis using the dip switches on the board and the max current setting is 3A per axis.
What current setting you use depends on the motor rating and  how it is wired.
I had just noticed this pin as well. I understand (now) what it is for, but how does Mach use it? Does mach use it? Do you need a custom M-code to drive it?
ie, is it really just another Output pin with a fancy label?

Cheers
Roger

Offline RICH

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Re: Current Hi/Lo setting?
« Reply #6 on: May 05, 2014, 06:19:30 AM »
Roger,
Don't know what "pin" you are talking about relative to current setting.
Some drives will limit the current when the motor  is not being pulsed / used to a lower value after a time period and then switch back to a higher current setting when pulsing starts again and you have a choice of setting the Auto Current reduction to on or off.

Mach3 has nothing to do with the current setting as Mach provides the pulses to the drive and the drive manages the power.
When current is reduced the motor holding torque is reduced.

I don't know what the TB drives do. You will need to sort through all the info to find out.
Sorry, but personaly I just don't address issues with the TB drives, and will reframe from making comment about them.
Ask the Chinese .............. >:D

RICH

 
Re: Current Hi/Lo setting?
« Reply #7 on: May 05, 2014, 07:17:55 AM »
Quote
Don't know what "pin" you are talking about relative to current setting.
Config
Ports & Pins
Output pins
Half way down the list: 'Current Hi/Lo'

Perhaps it was a passing idea to help allow stepper drives to automatically cut stationary power. Seems no-one ever uses it today? One could simply use any Output Pin of course, or hard wire it.
Mysterious hidden recesses of Mach3...

Cheers
PS: I am not into Chinese drives ...

Offline BR549

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Re: Current Hi/Lo setting?
« Reply #8 on: May 05, 2014, 11:54:18 AM »
I believe the "CurrentHigh/low is a signal that SHOWS when ANY axis is moving OR not moving. I used it for the lube pump signal. As long as it was ON the pump timer ran  IF it was just setting looking pretty the Pump timer did NOT run OR pump oil all over the floor(;-).

(;-) TP
Re: Current Hi/Lo setting?
« Reply #9 on: May 05, 2014, 05:35:45 PM »
Hi Terry

Greg at Warp9 says it is asserted (or cleared, whatever) after a few seconds of not-moving, to signal to stepper motor controllers that they can reduce holding power. Pretty much the same thing as you mentioned. Doesn't affect my DC servo motors.

Cheers
Roger