Digital Sidecar relay ports: correct voltage?

[Ether]

Can anyone please tell me what is the correct voltage reading on the red&white wires coming out of the relay ports on the digital sidecar?

We are measuring 4.2 volts in the active state.

We have a Spike relay connected to a relay port, and the Spike is not working.

By "not working", I mean the Spike LED remains orange and there is no voltage across the Spike's output. We thought maybe the sidecar got damaged and is not outputting the right voltage.

There is 12 volts across the Spike input, correct polarity.

The battery is sufficient; it runs the motors that drive the wheels.

We swapped out the Spike and the new one doesn't work either.

We understand the following chart and tested all four states

red=0 white=0 brake (both outputs grounded)
red=1 white=0 reverse (reverse output polarity)
red=0 white=1 forward (normal output polarity)
red=1 white=1 brake (both outputs +12)

Unless there's something I'm missing, the only hypothesis that seems to fit the facts is that the signal voltage is not correct.


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[Mark McLeod]

Do you see the Relay status lights (red/green/off) changing states while the Spike status light remains orange?

Normally, with those symptoms I'd say the Spike is not receiving a signal.

P.S. I checked my notes and I noted a 4.6v reading from a Relay output.

P.P.S. I checked the Spike documentation and it requires 3v minimum for the control signal.

[Ether]

Originally Posted by Mark McLeod

Do you see the Relay status lights (red/green/off) changing states while the Spike status light remains orange?

Normally, with those symptoms I'd say the Spike is not receiving a signal.

Hi Mark,

We saw the LED at the relay port on the sidecar change from green to off while the Spike relay remained orange.

We used a voltmeter to measure the voltage on the 3-wire cable (black/red/white) at the connector that plugs into the Spike. It measured about 4.2 volts (on the red and/or white wires) when active. So the Spike is getting a "signal"... I just don't know if it is the "correct" signal; I couldn't find a spec on what voltage the sidecar is supposed to output, nor could I find anything on the Spike datasheet about what input signal voltage level was required.



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[Mark McLeod]

It's on page 3 of the Spike document - Control signal: 3v minimum.

I'd consider this a problem with plugging the PWM cable into the recessed Spike connection. It can easily go into the slot, but miss the internal connector entirely even after repeated tries.

If you're reading a signal at the Spike end of the PWM then the cable and connection at the DSC sound fine.

[Ether]

Originally Posted by Mark McLeod

It's on page 3 of the Spike document - Control signal: 3v minimum

Thanks Mark. Could you post a link to this document? The doc I have does not have this info.

Originally Posted by Mark McLeod

I'd consider this a problem with plugging the PWM cable into the recessed Spike connection. It can easily go into the slot, but miss the internal connector entirely even after repeated tries.

Aha. That sounds more likely. I vaguely recall hearing something about this. We will look into it when we get the robot back.

We couldn't get it fixed in time, so we used the 24V solenoid break-out. All we needed was about 70ma. I asked a couple of students to find the specs for the output current capability of the 24V solenoid breakout, and they spent about and hour and a half looking but couldn't find it. You don't happen to have a link to a doc for that by any chance do you?


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[Russ Beavis]

cRIO sourcing module
http://sine.ni.com/nips/cds/view/p/lang/en/nid/14175

control system docs (including the official power and data diagrams and a link to the datasheets for the Digital Sidecar, PD and Breakouts)
http://www.usfirst.org/roboticsprogr....aspx?id=10934

[Ether]

Originally Posted by Russ Beavis

cRIO sourcing module
http://sine.ni.com/nips/cds/view/p/lang/en/nid/14175

control system docs (including the official power and data diagrams and a link to the datasheets for the Digital Sidecar, PD and Breakouts)
http://www.usfirst.org/roboticsprogr....aspx?id=10934

Thanks Russ. Right under our noses. How embarrassing. I think after we've all recovered from the last 48 hours we'll have a little team meeting about where to find this kind of stuff.


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[Vikesrock]

Originally Posted by Ether

We couldn't get it fixed in time, so we used the 24V solenoid break-out. All we needed was about 70ma. I asked a couple of students to find the specs for the output current capability of the 24V solenoid breakout, and they spent about and hour and a half looking but couldn't find it. You don't happen to have a link to a doc for that by any chance do you?


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If it's for a solenoid that's a perfectly fine solution.

If it's for anything else you will have to track down the issue with the Spike. <R65> restricts the Solenoid Breakout to solenoids only.

[Ether]

Originally Posted by Vikesrock

If it's for a solenoid that's a perfectly fine solution.

If it's for anything else you will have to track down the issue with the Spike. <R65> restricts the Solenoid Breakout to solenoids only.

I should say "thank you", but I think you've just ruined my whole day.

I think I'll wait a couple days before telling the team. They were so happy.

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[Mark McLeod]

For Spike technical info. the place to go is the manufacturer at VexPro and the Spike Relay specific page.

[PhilBot]

FYI... Don't forget there is a known LabVIEW VI problem associated with the RELAY control.

It's reported here http://decibel.ni.com/content/thread/6131?tstart=30 (and I only found it by accident).

If you are setting the relay to run in "Both Directions" it apparently works, but if you were like me and just wanted to turn something on, it was just dead.

Solution... open up the "RelaySet.vi" and connect the two "Relay Direction" terminals as shown in the NI post.

Phil.

Note: I really think a bigger deal should have been made about this. Is there a "known bugs" list anywhere...

I just "assumed" that the relay control would work..... It makes me start wondering about any code that should work, but doesn't..... coding error or known VI bug...

[Gary Bonner]

Originally Posted by PhilBot

FYI... Don't forget there is a known LabVIEW VI problem associated with the RELAY control.

It's reported here http://decibel.ni.com/content/thread/6131?tstart=30 (and I only found it by accident).

If you are setting the relay to run in "Both Directions" it apparently works, but if you were like me and just wanted to turn something on, it was just dead.

Is this correction necessary? Our compressor seems to be working fine. However, an electromagnet on a Spike seems to have a little delay in releasing. Could this issue contribute to that? We originally attributed the delay to residual magnetism and added code to briefly reverse the magnetic polarity, but haven't had a chance to test it out yet.

[PhilBot]

Originally Posted by Gary Bonner

Is this correction necessary? Our compressor seems to be working fine. However, an electromagnet on a Spike seems to have a little delay in releasing. Could this issue contribute to that? We originally attributed the delay to residual magnetism and added code to briefly reverse the magnetic polarity, but haven't had a chance to test it out yet.

If you are using the Compressor VI, then it's not required, however if you are using the Relay control direcly then it may be required, depending what mode you are using it in (forward, reverse or both).

However, if your relay is working at all, then it's probebly not required... it's a show stopper.

BTW.... Electromagnet..... ???? is this part of some active actuator?
Wouldn't this be dissalowed by <R53>.

<R53> Items specifically PROHIBITED from use on the ROBOT include:
A. Electric motors and/or servos different from, or in addition to, those in the KOP, with the exception of those specifically permitted by Rule <R52>.
B. Electric solenoid actuators (note: electric solenoid actuators are NOT the same as pneumatic solenoid valves – the latter are permitted, the former are not).

One assumes that when you turn on/off your electromagnet, something on your robot moves... Isn't that the definition of an "electric solenoid"...

Not my call... just pointing it out.

[Ether]

Originally Posted by PhilBot

Electromagnet..... ???? is this part of some active actuator?
Wouldn't this be dissalowed by <R53>.

Electromagnets are legal, but not as part of an integrated purchased assembly.

http://forums.usfirst.org/showthread.php?t=14205


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[PhilBot]

Originally Posted by Ether

Electromagnets are legal, but not as part of an integrated purchased assembly.
http://forums.usfirst.org/showthread.php?t=14205
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Wow, that's a pretty broad interpretation.
Electromagnets good, Solenoid Actuators Bad.

Make sure you have a printout of that Q&A on hand at all times

I just hope you don't get a finicky EE as an inspector.
There could be some big arguments there......