Acorn suddenly having issue turning on.

[Reedfirst]

Looks like for now a work around such as the one Posted by Gary Campbell or one which powers the Acorn Before the +5volt supply is the safest way to proceed for the time being.

[martyscncgarage]

OK, I think I may be closing in on the issue.

I am still researching but I believe the Beaglebone isn't powering up because it is seeing voltage on whatever I/O pins are connected to the step/dir pins on Acorn "CAPE" and sending this voltage back to the processor, Thus preventing it from turning on.

Maybe controlling a transistor or similar to turn on the auxillary +5volt power supply after the SYS_5V Pin goes high on the Beaglebone (p9/#8 on the actual beaglegbone) or VDD_3v3 Pin goes high (P9 #4 on the actual beaglebone) will solve this issue.

Taken from the Beagle Bone System Reference Manual

There are several precautions that need to be taken when working with the expansion
headers to prevent damage to the board.
1) Do not apply any voltages to any I/O pins when the board is not powered on.
2) Do not drive any external signals into the I/O pins until after the VDD_3V3B rail is up.
3) Do not apply any voltages that are generated from external sources.
4) If voltages are generated from the VDD_5V signal, those supplies must not become
active until after the VDD_3V3B rail is up.
5) If you are applying signals from other boards into the expansion headers, make sure you
power the board up after you power up the BeagleBone Green or make the connections
after power is applied on both boards.
Powering the processor via its I/O pins can cause damage to the processor

Thoughts anyone?

Yes, this is the assumption as I know it. Acorn must power up before the drives power up. If they are powered up first, they apply voltages on the STEP/DIR/ENABLE pins, back feeding Beagle Bone Green. BBG sees this and goes into a failsafe state and not power up until the issue is cleared.

The single power supply with dual voltage outputs helps but apparently the same issue could occur.

Gary's solution works because the Estop relay does not close until Acorn is up and happy. This is also typical in industrial control. An Estop relay closes enabling power to the drives.

Centroid Engineering is review this scenario now....hang in there until they finish the review.

[TheKitMill]

Andy...
I solved the issue on my board by running the 5volt power thru an output/relay to OKFault. More info and my hacked schematic near the end of this thread: viewtopic.php?f=60&t=1395&p=8266#p8266

Thanks Gary, I thought I killed the board. Everything was working fine on the bench with my test system no external 5 Volt required for the drives on my bench. But when connected to the DMM 4 drives and motors that need a 5 volts it was dead. Going to try your fix first thing monday morning before I replace the Power Supplies with a Dual system

[martyscncgarage]

Andy...
I solved the issue on my board by running the 5volt power thru an output/relay to OKFault. More info and my hacked schematic near the end of this thread: viewtopic.php?f=60&t=1395&p=8266#p8266

Thanks Gary, I thought I killed the board. Everything was working fine on the bench with my test system no external 5 Volt required for the drives on my bench. But when connected to the DMM 4 drives and motors that need a 5 volts it was dead. Going to try your fix first thing monday morning before I replace the Power Supplies with a Dual system

Did you try disconnecting the DYN4 drives from Acorn Step/dir terminal blocks and restarting Acorn to see if it's still ok?
On the latest hardware revision, the screw terminal blocks unplug from Acorn.

[TheKitMill]

Hi Gary

I will try that first. I have the board failure at about 7 last night just as was going to test drive the DMM motors with the control. I remembered a post from Marty and though I might have bricked it so I brought it home and was about to de-brick when I saw that others were having problems with the DMM 5 v common being in the circuit. I have a board that about 4 months old and just ordered two more for the next two machine so hopefully the new boards will not have this problem. Maybe Centroid could offer a board upgrade. I will let you know if how it goes. And nice work on the machines you have done as shown on your You Tube Channel

[TheKitMill]

Hi Mart, i thought it was Gary replying. You do great work too.

Chuck

[TheKitMill]

Andy...
I solved the issue on my board by running the 5volt power thru an output/relay to OKFault. More info and my hacked schematic near the end of this thread: viewtopic.php?f=60&t=1395&p=8266#p8266

Thanks Gary, I thought I killed the board. Everything was working fine on the bench with my test system no external 5 Volt required for the drives on my bench. But when connected to the DMM 4 drives and motors that need a 5 volts it was dead. Going to try your fix first thing monday morning before I replace the Power Supplies with a Dual system

Did you try disconnecting the DYN4 drives from Acorn Step/dir terminal blocks and restarting Acorn to see if it's still ok?
On the latest hardware revision, the screw terminal blocks unplug from Acorn.

Hi Marty

Got eh board wired up outside of the machine with a independent power supply It powers up ok. I will put it back in the system and reconnect to Centroid software independent of the DMM drives and see what happens. But at lease the board does not appear to be Dead.

[martyscncgarage]

Good news. Is your board the newer one with removable terminal blocks?
Are you connecting the DYN4 drives to the green terminal blocks? What schematic are you using?

[mael]

I also had the same problem when first figuring things out (5v for the drives). Im using a leadshine knockoff.
What i did was make a time on delay circuit relay. This way when 24v is turned on (applies power to acorn) it also powers the time delay circuit and in X number of seconds the relay closes and closes the connection for the 5v. The acorn is able to boot up correctly.

[TheKitMill]

Acorn Boots up as long as 5v to DMM drives not connected. I will rewire so Acorn Boots then the 5 V comes on. I have one of the older boards in this machine but have two more on order for the next two machine. And yes on connecting to green terminal blocks. I am using the schematic off the Centroid site.