Behavior of Summit CP688 photocell - McRabbet

[JJohnston]

I'm wiring the full bin sensor, and I tried to test the photocell. It's a Summit CP688 as recommended by McRabbet and the guy from the NC woodworkers' forum who devised the system originally. The system is wired per McRabbet's earlier wiring diagram, without the service switch at the photocell.

There does seem to be a delay, though. According to the instructions, if you wire it in daylight, it's in "dark" mode (energizes the A-B relay, and shuts off the Fasco) for about a minute, then shuts off, and the Fasco relay energizes. That's alright; I can understand it needing to initialize itself once it's powered.

However, after that, when I hold my hand over the eye, it should go into dark mode immediately, shouldn't it? It doesn't. There's about a 40 second delay going into "dark", or "bin full" mode, then another 40 second delay going back to "lighted", or "bin empty" mode.

[McRabbet]

It is possible that the company has added some delay in their internal circuitry as is common in many competitor's versions. They build in a delay so a passing car headlights at night won't activate the "daylight" mode and turn off the yard lamp. My original CP688 did react immediately. But perhaps it is not all that bad, because you don't want it to be super sensitive and have it trip with a passing dust stream versus a full blockage of the beam by a full bin. If you place the photocell 3-4 inches below the lid (use windows through the sides of your bin), then you should still have room in the bin for any additional sawdust pulled in during the delay and still meet the goal of protecting your filters.

[JJohnston]

Well, I'll go ahead with it the way it is. Can't hurt to try. Now, those indoor nightlights that have photocells react immediately. I wonder if one of them could be adapted if necessary?

[McRabbet]

:) I've just modified my old Bin Sensor Control circuit to make some key improvements. First, all of the 120 V power needed comes through the remote switch -- it now turns on the dust collector by energizing the H230B coil and power is also fed to the photo eye and candelabra bulb at the bin. Only the black power lead passes through the A-B relay upper set of contacts ([8 to 5] in their normally closed [NC] position), while the white neutral connects directly to the H230B coil, the lamp and the photo eye's neutral lead. I've used the other pair of contacts [1 to 3] to carry +12 V from a small wall wart transformer (not shown, but also powered by the remote switch) to the Normally open [NO] contacts to a 12 V strobe light (found on eBay (http://tinyurl.com/nb63on) for $9.77 delivered) mounted on the wall in the shop. When the photo eye sees a dark condition, the bin is full and the Red line activates the coil in the A-B Relay. The strobe blinks because its contacts are now closed and the 120 V power through the upper NC contacts to the H230B is cut. But notice there is a line from the NO side of that set of contacts through a "Relay Bypass Switch" to the coil. If the switch is closed, the H230B coil remains energized, but if the switch is open, it does not get power.

The obvious question is "Why defeat the sensor circuit by closing this Bypass switch?". The answer is for the case where you are planing a $50 board of nice figured maple or cherry and the DC Bin fills up! You'll want to leave that switch set to closed until you finish the planer pass so your DC continues to pull sawdust and chips! It is doubtful that 30 seconds or so of "over-ride" time will impact your filters, but stopping the DC while in the middle of the board could ruin it. When you finish the board, turn off the planer and move the switch to the open position and the DC will stop. Alternately, you could just click on the remote to turn off the 120 V power and it all stops.

These improvements help lengthen the life of the photo eye and candelabra bulb, and avoids a few problems with the old circuit. If the 7 Watt bulb is left on as before and if it burns out, the A-B coil is activated even though the remote is off. The shop indicator would also light up. Secondly, now the remote control manages all of the 120 V power -- if the bin needs servicing, it is switched off and the system cannot start up. But if you carried the remote in your pocket, you could turn it on after service to insure the bin lid is on tight and the lamp operates OK.

[JJohnston]

You make a good point about being able to prevent the DC from shutting down unexpectedly.

[McRabbet]

I've also post this in my old Bin Sensor thread, here (http://www.clearvuecyclones.com/Bullentin/showpost.php?p=4903&postcount=12).