Line sensors and solenoid breakouts

Team Update 5 says:

<R60> Solenoid Breakout outputs shall be connected to pneumatic valve solenoids or photoelectric sensors, PN 42EF-D1MNAK-A2 only. No other devices shall be connected to these outputs.

How would we go about connecting the photoelectric sensors to the solenoid breakout? Signal? Power? Both?

  1. Power only. Signal goes to the DSC.

  2. There are three ways to power your line sensors:
    A: 20 amp breaker from the PD board (power and common only)
    B: 12v through solenoid board (gets you nothing more than the above option, except you have to wire to those tiny pins instead of WAGO’s)
    C: 24v through solenoid board (gets you a stable 24v supply, at the weight expense of another solenoid module to run off a 24v supply, assuming you are either not using the solenoid board or are using 12v solenoids)

You can choose. I would go with A unless I had voltage stability issues or weight issues (those sensors weigh a whole 140 grams each!, with 3 that’s a whole pound), at which point I would probably remove the sensor for lack of usefulness.

The 2011 KOP includes three Allen-Bradley PHOTOTSWITCH 42EF-D1MNAK-A2 proximity/line sensors. These have a specified 10.8 V to 30 V DC power supply. The cable jacket print says the cable attached to (and integral
to) the sensor is a bundle of four 22 AWG wires. (Also, they’re UL AWM style 2464 with registration number E24546).

These sensors cannot be powered by the digital sidecar because 12V is not available. That leads us to the power distribution board (PD Board). Rule R39F requires us to protect this branch circuit with a 20A breaker. R39 does not allow any smaller breaker to be used for any type of load.

Rule R40 states that the minimum wire size for a 20A PD Board branch circuit shall be 18 AWG. Therefore, we cannot connect an Allen-Bradley sensor to the PD Board and use a 20A breaker. This is a good safety rule. However, the rules appear to prohibit us from using a smaller, properly sized breaker.

Should I interpret the rules to allow me to use thinner wire after a second breaker or fuse? I would add another smaller fuse before the sensors and after the 20A breaker in the PD Board. Aside from this I see no legal way to connect the Allen-Bradley sensors in the KOP to the FRC control system. I am aware of the blue box on R39 but unclear if it allows me to violate R40 by connecting the sensor with integral 22 AWG wire. This seems technically valid but it’s unclear if this is FRC legal.

Thank You for clarification.

NEW Apple Corps FIRST Robotics Competition Team #0093

Answer: GDC

Per R40, all active PD Board branch circuits shall be wired with appropriately sized wire - but the branch circuit may include intermediate elements such as COTS connectors and splices.

Please also reference Team Update 5.

The only problem with option A is addressed by the Q&A posted above. It makes it a little interesting to wire the sensors to the PDB, because you have to deal with wiring so that the appropriate sized wire is connected to the PDB, and then connect the sensors’ wire to the bigger wire later in the circuit.

The GDC has previously held (and stated this year) that wires integral to COTS components were allowed. Read part 2 of the GDC’s reply.