instead of running 6 wires to the sensors?
I’m sorry, I just don’t understand what you’re asking here?
Are you asking for a way to simplify the wiring of the Rockwell light sensors?
Please elaborate.
I’m pretty sure you can. I believe that falls under the “multiple low-current devices” rule. Let me look it up.
<R39> part F
Custom circuits and sensors powered via the cRIO-FRC or the Digital Sidecar are
protected by the breaker on the circuit(s) supplying those devices. Power feeds to all
other custom circuits must be protected with a dedicated 20-amp circuit breaker on the
PD Board.
[quote]In addition to the required branch power circuit breakers, smaller value fuses or
breakers may be incorporated into custom circuits for additional protection.
[/quote]
To clarify the OP’s question. 6 wires include 3 positive and 3 negative wires for the 3 sensors provided.
that’s what I did and it works fine but with all of the daisy chaining it looks awful.
Oh, now I get it, tying the outputs of the sensors together to save wiring.
Well, electrically, that should work fine, one of the wonders of open-collector outputs, though I’m not sure how the ruling goes on that.
Just remember <R40>
<R40> All active PD Board branch circuits shall be wired with appropriately sized wire:
Application Minimum wire size
40A circuit 12 AWG (2.052mm)
30A circuit 14 AWG (1.628mm)
20A circuit 18 AWG (1.024mm)
between the PD Board and the Analog and/or Solenoid Breakouts if a common power feed is used 18 AWG (1.024mm)
between the PD Board and the Analog and/or Solenoid Breakouts if individual power feeds are used 20 AWG (0.8128mm)
between the PD Board and the cRIO-FRC 20 AWG (0.8128mm)
between the PD Board and the radio 20 AWG (0.8128mm)
pneumatic valves 24 AWG (0.5106mm
What we did is used the terminal strip.
For the 12V power:
I used a butt connector and had basically one input, and three outputs, 2 on each side. So we had our positive and negative wire going to a yellow butt connector, then 3 loose ends.
For the Digital Input Cables, we got the 5V power, and the signal and brought them to the terminal strip. We put a resistor between the 5V DIO power, and the signal.
So, if you do the math, that’s 4 spots on the terminal strip used by every sensor, and 3 sensors. You just so happen to have 12 terminations on the terminal strip.
With the resistor between the 5V and the signal, what you did is create a pull-up for the circuit using a pull-up resistor.
I then used the white signal wire from the photo sensors. The white is the D.O. connection, meaning that when it sees the dark, it turns on. When it turns on (aka sees the dark), it pulls whatever is on it to ground. You wire the white wire to what is usually the white signal wire from the Digital Side car.
So, when it’s dark, the white signal wire going to the sidecar should be at 0V when tested to ground. When it sees the tape, the signal goes out, so the pull-up resistor should pull it up to ~5V.
As for what resistance to use… I didn’t do the math. We’re using a 1K Ohm resistor. We haven’t checked it to see if works yet. We hooked it all up at the last second, and the programmers had some code in to read it, but it didn’t work. It’s the first thing we’ll look at when we get back.
Just remember that you’re probably using 1/4W resistors. What this means is that they can keep their rating when only pulling through 1/4 of a watt.
With a 5V power supply, you don’t want to go with a resistance lower than 100 ohms. At that point, you may have some toasty resistors. You may not want to go that low. I don’t know what the sensors can handle (like if they can pull down the 5V supply).
The Digital Sidecar DIO pins are internally pulled up to 5V using 10K resistors.
No matter how you wire it, you might want to think about including a quick and easy way to swap out a sensor in your design. Just in case of field damage.
Sweet! Always a cool thing to learn something. So do the sensors work fine with the internal 10K ohm?
They work perfectly. It’s almost as if the Digital Sidecar was designed to handle open-collector sensor outputs directly. :rolleyes:
Please be advised that the PD terminals work best and most reliably with #18 AWG wire or larger.