Anomalous Behavior of Beagle Bone Green on Acorn Board with separate power supplies
Posted: Thu Jan 25, 2018 4:21 pm
This is a follow on to the discussion located here viewtopic.php?f=60&t=1395 "No Connection to Acorn Discovered" Error. It is also closely related to this discussion viewtopic.php?f=60&t=1429 Acorn suddenly having issues turning on. I didn't want to hijack Reedfirst's thread so I've started a new one. I'll apologize in advance for any redundancy between the latter thread and this one.
The problem is that Beagle Bone Green (BBG) will not boot up in some scenarios. It seems to involve systems which are using both a 24 and 5 VDC power supplies. It appears that at least four of us have experienced some form of this issue. In my system I have observed the following:
1. After wiring the Acorn board into my system and turning the power on BBG booted and all the appropriate leds came on.
2. I turned the power off to tighten a loose wire on one of the drivers. Turned the power on and BBG booted again.
3. Approximately 40 mins. later the BBG dropped out (no led lights or ethernet cable lights lit). I've only observed this behavior once.
4. Currently I can turn on power if the mill has been powered down for an extended period of time and BBG will boot up.
5. If I cycle the power off then back on after the BBG initially boots it will not reboot the second or subsequent times.
6. If I disconnect the 5 VDC power supply then power up the mill the BBG always boots. I can then reconnect to 5 VDC PS and the BBG stays on.
7. The BBG acts as if it is bricked. The debricking procedure is not required to restore function. Disconnecting the 5 VDC PS then rebooting works.
8. It doesn't matter if the drivers are powered on or off. Whether the 5 VDC PS is on or off determines BBG behavior (mostly, see #4).
9. The work around on my system is to power up the BBG first then power up the 5 VDC PS. BBG always boots if I do this.
My system is wired up per the Leadshine schematic. Drives are Leadshine MA860H (3). 24 VDC PS is the Meanwell unit supplied with the Acorn board. The 5 VDC PS is an ATX dual output 5 and 12 VDC unit. The problem would appear to be hardware related as my observations including #4 and down involved the CNCPC being booted up but neither CNC12 nor the Wizard running.
Conjecture from the above referenced threads as to the cause of the problem include:
1. Voltage ripple issues related to the 24 and 5 VDC switching power supplies having their respective commons connected (see the Leadshine schematic) inducing unexpected or unusual behavior (in the BBG?). Is the quality of the PS an issue?
2. Conflict between the Leadshine drives and the Acorn board and BBG when the drives are powered up at the same time as the Acorn. (In my case this doesn't seem to be the problem)
3. BBG protection features preventing it from booting if the 5 VDC PS Powers up before the 24 VDC power supply in systems with separate power supplies.
Proposed work arounds:
1. Dual output PS supply rather than separate 5 VDC and 24 VDC power supplies. May not be the solution as andyolney in Reedfirst's thread is using a dual output PS. May be worth checking further though.
2. Gary Campbell has provided a schematic with a work around which solved the problem for him. download/file.php?id=1588
3. Similar to Gary's approach, starting the 5 VDC PS after the BBG boots works for me. I have two switches on my cabinet. One powers up everything but the drives. The second powers up the drives. I always turn on the first switch prior to the drives so it was a simple matter of wiring the 110 VAC power for the 5 VDC into the second switch which turns on the drives.
4. Firmware update to BBG to address the issue? I don't know if this is possible but might be worth looking into.
5. Isolating the 5VDC and 24 VDC power supplies?
6. Using higher quality power supplies?
I want to thank Gary Campbell for pointing me towards the problem and suggesting a possible work around that ultimately led me to the dual switch approach. Thanks Gary!
The problem is that Beagle Bone Green (BBG) will not boot up in some scenarios. It seems to involve systems which are using both a 24 and 5 VDC power supplies. It appears that at least four of us have experienced some form of this issue. In my system I have observed the following:
1. After wiring the Acorn board into my system and turning the power on BBG booted and all the appropriate leds came on.
2. I turned the power off to tighten a loose wire on one of the drivers. Turned the power on and BBG booted again.
3. Approximately 40 mins. later the BBG dropped out (no led lights or ethernet cable lights lit). I've only observed this behavior once.
4. Currently I can turn on power if the mill has been powered down for an extended period of time and BBG will boot up.
5. If I cycle the power off then back on after the BBG initially boots it will not reboot the second or subsequent times.
6. If I disconnect the 5 VDC power supply then power up the mill the BBG always boots. I can then reconnect to 5 VDC PS and the BBG stays on.
7. The BBG acts as if it is bricked. The debricking procedure is not required to restore function. Disconnecting the 5 VDC PS then rebooting works.
8. It doesn't matter if the drivers are powered on or off. Whether the 5 VDC PS is on or off determines BBG behavior (mostly, see #4).
9. The work around on my system is to power up the BBG first then power up the 5 VDC PS. BBG always boots if I do this.
My system is wired up per the Leadshine schematic. Drives are Leadshine MA860H (3). 24 VDC PS is the Meanwell unit supplied with the Acorn board. The 5 VDC PS is an ATX dual output 5 and 12 VDC unit. The problem would appear to be hardware related as my observations including #4 and down involved the CNCPC being booted up but neither CNC12 nor the Wizard running.
Conjecture from the above referenced threads as to the cause of the problem include:
1. Voltage ripple issues related to the 24 and 5 VDC switching power supplies having their respective commons connected (see the Leadshine schematic) inducing unexpected or unusual behavior (in the BBG?). Is the quality of the PS an issue?
2. Conflict between the Leadshine drives and the Acorn board and BBG when the drives are powered up at the same time as the Acorn. (In my case this doesn't seem to be the problem)
3. BBG protection features preventing it from booting if the 5 VDC PS Powers up before the 24 VDC power supply in systems with separate power supplies.
Proposed work arounds:
1. Dual output PS supply rather than separate 5 VDC and 24 VDC power supplies. May not be the solution as andyolney in Reedfirst's thread is using a dual output PS. May be worth checking further though.
2. Gary Campbell has provided a schematic with a work around which solved the problem for him. download/file.php?id=1588
3. Similar to Gary's approach, starting the 5 VDC PS after the BBG boots works for me. I have two switches on my cabinet. One powers up everything but the drives. The second powers up the drives. I always turn on the first switch prior to the drives so it was a simple matter of wiring the 110 VAC power for the 5 VDC into the second switch which turns on the drives.
4. Firmware update to BBG to address the issue? I don't know if this is possible but might be worth looking into.
5. Isolating the 5VDC and 24 VDC power supplies?
6. Using higher quality power supplies?
I want to thank Gary Campbell for pointing me towards the problem and suggesting a possible work around that ultimately led me to the dual switch approach. Thanks Gary!