Legal to use solenoid breakout as a source of power?

[samn122]

My team wants to power the Allen-Bradley PHOTOSWITCH 42EF-D1MNAK-A2 through the solenoid breakout since it is capable of outputting 24 volts. I can't find any rules or restrictions in the manual on this issue. Does anyone know if it's legal?

[FrankJ]

R51 along with table 4-4 control what can be connected to the solenoid breakout board. R69 controls the total load for the solenoid breakout. The definition of custom circuit seems to cover photo switches. If the photo switch is a custom circuit & the total load on the solenoid breakout is under R69 the answer would be yes. Otherwise no.

[Alan Anderson]

Originally Posted by FrankJ

R51 along with table 4-4 control what can be connected to the solenoid breakout board. Unless the photo switch falls under a custom circuit definition, I think the answer would be no.

Fortunately, sensors such as photo switches do fall in the category of custom circuits. The only thing you might need to watch out for is the maximum current that can be supplied by the Solenoid Breakout.

[MrRoboSteve]

I'm curious why you want to run them at 24v. We run them off of the PDB at 12v without issue.

[Mark McLeod]

Those sensors are rated down to 11v, so they perform more consistently while on a regulated power source.
Really lower than than in actual usage, but they can stop functioning at the lowest voltage dips we can see when driving a lot of motors at stall on robot.
They start functioning again when the voltage later rises, so if they aren't actively being used during a pushing contest, then the drivers may never notice.

[Ether]

Originally Posted by MrRoboSteve

I'm curious why you want to run them at 24v. We run them off of the PDB at 12v without issue.

See the bottom of Page 2 of this document for an explanation.

[MrRoboSteve]

Thanks!

We had some issues last year with the line detectors that could be explained by this.

S

[Al Skierkiewicz]

If the solenoid module is wired to the PD +24 volt power supply, that is maintained down to a battery terminal voltage of about 4.5 volts. I think that is a good choice for a sensor that requires constant power supply.