BNC Output not working

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BNC Output not working
#1
We have the BPOD R2.  We had previously been using both BNC outputs for triggering TTL devices. Both outputs suddenly stopped producing 5V. The benchtop testing from BPOD console does not give 5V when manually turned on either. 

Any help is appreciated.
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#2
Hi Ryan,

Four labs have now reported failure of the BNC output channels in the past few weeks. So far each case occurred when driving a TDT device (e.g. https://sanworks.io/forum/showthread.php?tid=367)

What device(s) did you have the BNC output channels  connected to, and which specific connectors on the device(s)?

As a temporary workaround while we solve the issue, one thing I'd try is triggering via the 3.3V LED channel on a free behavior port. You'd connect it to TDT via the LED + and - terminals on a port interface board and wire to BNC adapter. Then, in your state matrix (assuming behavior port 4) you'd use: {'LED4', 1} and {'LED4', 0} to make it high (3.3V) and low (0V).

Thanks,
-Josh
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#3
(09-05-2018, 04:27 PM)Josh Wrote: Hi Ryan,

Four labs have now reported failure of the BNC output channels in the past few weeks. So far each case occurred when driving a TDT device (e.g. https://sanworks.io/forum/showthread.php?tid=367)

What device(s) did you have the BNC output channels  connected to, and which specific connectors on the device(s)?

As a temporary workaround while we solve the issue, one thing I'd try is triggering via the 3.3V LED channel on a free behavior port. You'd connect it to TDT via the LED + and - terminals on a port interface board and wire to BNC adapter. Then, in your state matrix (assuming behavior port 4) you'd use: {'LED4', 1} and {'LED4', 0} to make it high (3.3V) and low (0V).

Thanks,
-Josh

Thanks for the quick reply Josh!

To answer your question we were using the BNC outputs to drive 1) 5V trigger to relay for water valve and 2) save file trigger to our Ephys system.  That being said, we were not seeing anything on the oscilloscope when we ran the triggers directly from the State Machine into the scope, so it appears to be a BPOD hardware issue.  Your workaround has worked well for now, I've been able to generate working triggers from the LEDs. In case someone runs into the same issue and is running into the same error that I was: 

The state matrix code syntax is a little different. {'LED', 4} = LED full power on behavior port 4, {'LED', 3} = LED full power on behavior port 3.  This is how I had to code it to make each individual trigger recognize the port as "LED3" and "LED4" just came back with 'Check spelling of state' errors.
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#4
Hi Ryan,

Thanks for the correction - it's {'LED', N} where N is the port number

I'm worried about the relay - if you're trying to drive a relay directly from the BNC output channel, it's possible the BNC isolator IC was damaged. Mechanical relays typically require more current than a TTL I/O line can provide directly, and without a flywheel diode, they can discharge backwards into the circuitry when the magnetic field collapses as they are switched off. This page has a few example driver circuits (I'd use the version labeled 'N-channel MOSFET'. Another option is to use a solid state relay, which can directly interface with TTL logic (though you'd still need a flyback diode).

What kind of valve are you trying to drive? State machine r2's  onboard valve driver is powerful enough for most things you'd use in a behavior lab, and is robust against most failure modes.

If you contact us at sales@sanworks.io, we'll send you a shipping label to return the machine for repair. We can have it back to you in under a week.

-Josh
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#5
Regarding TDT triggering issues, fortunately several labs have solved theirs as described on this thread.
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