Single PowerOff mode request ignored, multiple obeyed

RMP 210, 220, 440LE, 440SE, 440 Omni
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bch36
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Single PowerOff mode request ignored, multiple obeyed

Post by bch36 » Tue Aug 13, 2013 1:21 pm

While implementing the new operational modes (in this case PowerOff mode), I stumbled across a potential issue.

I'm currently sending a steady flow of 0 drive commands to the platform, and inserting a single PowerOff mode request into the stream. This command seems to be ignored. (e.g. drive drive drive POWEROFF drive drive drive, etc.)

If, however, I add a steady stream of PowerOff mode requests to the stream of messages, such that the drive commands and mode requests alternate, the platform will power off appropriately. (e.g. drive POWEROFF drive POWEROFF drive POWEROFF, etc.)

Is this expected? Should I continuously send PowerOff mode requests until they are achieved? I would expect that a single mode request would be honored.

I'm using an AA revision CCU with the new braking firmware.

Thanks for looking into this for me!

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phussey
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Re: Single PowerOff mode request ignored, multiple obeyed

Post by phussey » Thu Aug 15, 2013 2:57 pm

A single power-off mode request will be granted. Depending on your application timing the request may be getting ignored because more than one command in a 10ms frame is received. The maximum data rate is 100Hz, so if you are sending drive commands at 100Hz and injecting the poweroff it would be potentially ignored.

I will look into this further and try to replicate the behavior to understand what is going on.
PATRICK HUSSEY
Principal Engineer

STANLEY INNOVATION, INC
www.stanleyinnovation.com

bch36
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Re: Single PowerOff mode request ignored, multiple obeyed

Post by bch36 » Thu Aug 15, 2013 4:21 pm

Thanks for looking into this, Patrick. We've sent drive commands between 10 and 40 hz, but never closer to 100 hz.

Do I understand correctly that only one command every 10 ms is accepted? Would another command within that 10 ms window be buffered or discarded? We're sending the mode switch command at effectively the same time as our drive commands, so if too-rapid commands are being discarded, that might be our problem.

If that is our problem, I can put a small sleep before and after sending the mode switch.

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phussey
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Re: Single PowerOff mode request ignored, multiple obeyed

Post by phussey » Fri Aug 16, 2013 11:23 am

Yes only one command is accepted in a 10ms frame. If more than one is received they are both discarded.
PATRICK HUSSEY
Principal Engineer

STANLEY INNOVATION, INC
www.stanleyinnovation.com

bch36
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Re: Single PowerOff mode request ignored, multiple obeyed

Post by bch36 » Mon Aug 19, 2013 1:06 pm

Thanks! This looks like exactly what our problem was. Putting a sleep before and after seems to fix the issue.

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