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Re: Solenoids
Posted by Lloyd Burns at 1/29/2001 12:30 AM EST
Other on team #188, Woburn Robotics, from Woburn Collegiate and Canada 3000, ScotiaBank, Royal Bank Financial.
In Reply to: Solenoids
Posted by Alan Partington on 1/28/2001 1:44 PM EST:
: Has anyone been able to control the double solenoids so that you can control how far the pistons go out.
: Thanks alot,
: Alan
. In the pneumatics booklet, there is a clue in the paragraphs on the double-coil valve. It is important to remember these coils control pilot valves, not the main valve, so pressure must be present or you will neither see nor hear any action at all.
. The action of turning on the valve (apply voltage to coil A) allows the pressure from port P to push the valve to allow air to go from P to A (and B goes to its exhaust port), while turning off the current to coil A stops the flow from P to A, but it does not connect A to the exhaust port either. Both B and A are isolated, neither at pressure nor at atmosphere. The result is that the piston stops where it is. To further extend, pulse A again. To retract, pulse coil B which pushes the main valve all the way back, connecting port A to the exhaust, while P is now cleared for port B, retracting the cylinder.
. By placing a flow control (the gray, right-angled little spigots) in the line to P, (not a good idea - low pressure = erratic operation) or in the air lines from valve to cylinder, or yet again, in the exhaust ports, you can slow down the piston to a controllable speed, and you can stop it at any extension you need. Have you tried putting 60 PSI on the 3/4" bore cylinder (uncontrolled speed = recoil !!!) ? :-)
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