Phidgets Spatial 3/3/3 on RaspberryPi Detach event - ESD?

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jjbunn
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Phidgets Spatial 3/3/3 on RaspberryPi Detach event - ESD?

Postby jjbunn » Thu Dec 15, 2016 11:30 am

We have an intermittent problem with a Phidgets Spatial 3/3/3 1056 attached to a RPi 3 Model B, where the Phidgets detaches occasionally. The Phidgets is connected to a powered hub, which is connected to the RPi.

The application will run for many hours without a detach, and then we will see several over a few hours. In extreme cases, the Phidgets will not re-attach, and so our data collection halts.

Having turned on Phidgets logging, we see the following types of entries:

Code: Select all

ERR: ReadThread exiting - unexpected timeout (could be an ESD event)
WARN: PHIDGET_USB_ERROR_FLAG is set - cycling device through a detach
WARN: PHIDGET_USB_ERROR_FLAG is set - resetting device.
ERR: WriteThread exiting - CPhidget_write returned : 3
INFO: New device in CUSBBuildList: 1/24
INFO: Using Control Endpoint for Host->Device communication.
INFO: WriteThread running
INFO: ReadThread running


When the detach events occur, they do so typically while the RPi is doing I/O, either to the network (we use a wired connection) or to the SD card.

The implication from the error log seems to be that the detach events are caused by electomagnetic interference. We have tried situating the Phidgets far away from the RPi (a few feet), but this did not help.

itsalltoomuch
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Re: Phidgets Spatial 3/3/3 on RaspberryPi Detach event - ESD

Postby itsalltoomuch » Thu Dec 22, 2016 7:21 pm

Hi, don't know if this will help but we are running many raspberry pi 3/bs with a 1044 located close by and were getting unexpected detaches. We found that this was caused (in our case) because the daemon that had the 1044 attached occasionally did a print to stdout :o). Once removed, problem went away.
Steve

jjbunn
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Re: Phidgets Spatial 3/3/3 on RaspberryPi Detach event - ESD

Postby jjbunn » Thu Dec 22, 2016 8:31 pm

itsalltoomuch wrote:Hi, don't know if this will help but we are running many raspberry pi 3/bs with a 1044 located close by and were getting unexpected detaches. We found that this was caused (in our case) because the daemon that had the 1044 attached occasionally did a print to stdout :o). Once removed, problem went away.
Steve


Hi Steve,

After much experimenting, we found that adding a big ferrite ring and looping the Phidgets USB cable through it worked wonders: reduced the detach rate to around 6 per day from around 60. We are now wondering whether the USB cable is unshielded twisted pair, as it should be, or not ...


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