**RESOLVED** brake enable

[Riley]

I am having some trouble figuring out how to use the brake enable to close a relay contact. Also is it possible to enable the z axis the wait a tenth of a second before letting the brake go to avoid a position error? The column is pretty heavy and it travels downward just enough to create an error. But then again the tuning could be a little off, not sure. I am using mach/ajax GPIO4D/ MPU11. I'm also looking for some documentation on programming brain controls, the manual that I have seems to be written around the DC310. If there is one just for the system I have could someone direct me to it. Thanks

[please no smoke]

I am fighting the brain battle my self. I cannot find good documentation on it. The best thing I found is that artsoft (mach 3) have some videos on their site. My biggest problem is trying to find out where and what all the outputs and inputs are called.

I assume that you are referring to the drive enable that comes off the gpio4d where the drives connect. It looks like this is run by the Ajax Enables brain. All that brain does is takes the enable signal from mach I think and passes it on to the mod bus outputs 351-353 to enable the x, y, and z axis. I am barely understanding this my self but you should be able to use the brain editor to add a timer into the brain program.

[Riley]

I did manage to make a new brain and have the output from that axis closing one of the onboard outputs to power the brake. The only 5V relay I could find was right at the current limit of 90mA for the open collector output, that made me nervous. The brain seems to work fine, but I could use a chart defining the input and output addresses.

[please no smoke]

Me too. There is a partial table at the end of the ajax manual posted on this forum. The mach manual from artsoft web site also has a one page table I believe. A master list with more detail would be helpful.

[Centroid_Tech]

Riley,

The GPIO4D does have a few relayed outputs. You can hook the axis brake to one of those outputs, as long as they are not being used by anything else. The one motor brake pin will be hooked to the GND of the motor brake power supply. The other motor brake pin will connected to the one side of the output relay while the other side of the output relay is connected to the V+ of the motor brake power supply.

[Riley]

That is exactly what I'm doing. I have a made a simple brain that looks at the state of "enable3" and closes an output when enable3 goes high. Seems like once in a while z will drop .0025 before the amp sends holding current to the motor. But it sometimes stays put? I imagine once I run it a little it may loosen up a little and require a timer. Anyone else using a timed release for a brake? And if you did that could you clamp the brake before disabling the drive output? Maybe I'm just over thinking it.

[ajaxaaron]

Hi Riley,

It might help to use the state of "ModBus-Output-353-Bit Only" instead of "Enable3" in your brain -- the Ajax Enables Brain passes Enable3 through that output to tell the MPU11 to provide power to the motor, but your brain might be firing off first (releasing your brake). If that doesn't fix it, you can add a timer to the brain by highlighting a block so it turns green, then clicking the + symbol, then clicking TIMER. You may need to invert the input and outputs from the timer too... The attached example shows it pretty well (you'll obviously need to change it for your own purposes).

Good Luck,
-Aaron

[ajaxaaron]

A master list with more detail would be helpful.

A master list is not provided because the mapping depends on the actual hardware being used (DC3IOB, GPIO4D, etc). In general, a brain can use "ModBus Input 1 through 32 Bit Only" to get the raw input values coming from the MPU11, and "ModBus Output 1 through 32 Bit Only" to twiddle the relays. For example, "ModBus Input 11 Bit Only" can be used by a brain to read the raw EStop input coming from the MPU11. The images below show the Input/Output maps for 3 of the boards (others can be found in the Hardware Docs PDF directory of the Installation CD).

-Aaron