[dfurlano]

Looking for a suggestion. I use a G540 and output 6 is a constant problem.

Works for about a year then it has to go back for repairs.

I would like to find a different way to control my solenoids other than the G540.

I have a second parallel port that I can use to trigger the solenoids but I need something to trigger them.

As seen in the wiring diagram they currently use a 12v power supply that I can isolate from the G540. I can hook into LPT2 and disconnect output 6 from the G540.

Just need to know what board I can use.

TIA

dan

[john-100]

its possible connecting two solenoid valves to the one output terminal on
the Gecko G540's output is overloading the output FET transistor

I would of connected a diode across the coils
(the cathode connected to +12v)

If you have it repaired again , use a relay to switch the 12v supply to
the solenoids or a large power transistor

you could make or buy a relay board like CNC4PC's C37 relay board
and connect it to a spare output on your second printerport

John

[dfurlano]

I am sure you are correct about the overloading. I think this is the third time this has happened. I have to keep a spare G540 because it always happens when I don't have time to send it back for repair.

I did connect a diode across the coils.

I bought the C15 which is a dual board. I will use the LPT2, one solenoid is for water the other air. This way I can separate them in Mach.

Thanks.

Dan

[john-100]

Hi Dan

as a matter of interest ,whats the resistance of the coils ?

the C15 board is a good solution, as you say it gives you individual
control of both valves

John

[Al_The_Man]

There are many TTL (5v) operating power FETs that can be connected direct to the P.P.
If you do a search here for 2n7000 you can get the idea, but the difference is, instead of a relay you use the FET to switch the 12v solenoid.
If you use a separate 12v supply than the PC P.S. for the coil, then just connect up the commons only.
Al.

[dfurlano]

I need something packaged because I am really afraid I will fry my PC. With an optoisolated board I feel safer. Electronics and me just don't mix some days.

BTW here is the solenoids I am using.

3/8" Electric Solenoid Valve 12-Volt Air, Gas,Fuel B20N | eBay


BTW I ordered the board from CNC4PC about noon and I just got an email that it was in the mail today. I really like businesses that ship fast. Drives me nuts when I order something online and it takes two days to ship it.

[METALTEK]

You should place a relay between your 540 and your solenoids. you want ones that have snubbers built in. (these will prevent voltage feedback to your signal source). I have controlled many large voltages and motors this way including 440 3 phase with no problems.

[dfurlano]

Specifically what relay are you suggesting? Although I am getting a board that will eliminate the 540 someone else may have the same issue.

[john-100]

Hi Dan ,

it would depend on what your controling
but for your solenoid valves some thing like this :-

http://www.farnell.com/datasheets/1306720.pdf

or for a large mains powered motor some thing like this :-

Buy Contactors CONTACTOR AC3 5,5KW,1S,24V ABB GJL1313001R0101 online from RS for next day delivery.

John

PS
plug in 48v dc relays have been used in old machine controls ,the sockets had screw terminals

eg http://uk.rs-online.com/web/p/genera...relay/2565240/

[METALTEK]

What i am referring to is use a 5volt relay with diode protection and use it to switch a larger 12volt relay to control your valves. The valves use more amperage than most small relays contacts are made for. This will isolate the voltages and each step and give you protection from voltage feedback. You could even operate contactors or small motors with your second relay.

[dfurlano]

this is what I ended up with.

[john-100]

Hi Dan ,

looking at the limit switches connected to the 2nd printer port

I would not connect the +5V directly to the limit switch
use some thing like a 2K2 resistor
this will limit the current into the port
if either the computer is off or the port is at a logic 0 due to an error

John

[dfurlano]

This is the homing switch I am using.

http://reprap.org/wiki/OptoEndstop_2_1

[john-100]

Hi Dan ,

an opto isolator , that makes a difference

John