Hi, I would like to use an electromagnetic lock, and be able to control it through a serial port, I have seen 2 types of this locks, fail safe I think is the one that stays locked after power loss. The problem is that In order for them to open an electric "spike" is needed, do you know of any boards that connect to a serial interface that can send the spike?
thanks in advance
Yes.
No. All you have to do is turn on and off the power supply. That may be either AC or DC, 12V or 24V, depending on which lock you've purchased. Depending on the lock and application, there may be a maximum duration you want to apply that power; check its specs, and either have the program apply this limit or build a timer into your control box.
So all you really need is a serial-controllable switching box, relays or triacs as you prefer, which can handle an inductive load. Anyone who sells lab-control equipment should have something like this, though it may be parallel-controlled. Or you could run the serial port into an X10 controller and pass the signal to an X10 module which would switch that supply. I'm fairly sure the manufacturers of electronic locks do have controller boxes which can be interfaced to a PC, though I'm not sure whether they're using serial, parallel, USB or Ethernet these days. Finally, a competent electronics hacker ought to be able to rattle this off fairly easily given the above information.
It is my memory that fail safe unlocks when the power is off "occupant safety". Fail secure remains locked, which secures the building.
Just an old memory from back when.
Oops. I did get that backward. Sorry; I've just come off a week of long hours and short sleep.
Definitely would not recommend this unless occasional random lock / unlock is OK for your application. You also have to tolerate occasional failures to lock or unlock. X10 fails silently when there is a problem sending or recieving a signal. Two signals at once causes a failure in unspecified ways.
Daniel
There are closed-loop versions of the X10 protocol, and controllers/software which understand these. They cost a bit more.
Unless that's a development in just the last year, you must be talking of another scheme. There are X10 modules that can report their status (two-way modules) but it's up to the software to ask what state the device is in (on or off) after sending a command. If a command is sent at the same moment that another device sends a signal, the commands can intermix, causing a the second (or third) device to act on the command.
Some of the newest devices will check to see if a powerline command is being sent before they send out a signal, but not all. I don't know of any that detect and resend after a failed command.
If it's closed loop, it's not X-10. There are other protocols meant to be sent over the powerlines that are more robust.
You can read the documents on the X10 protocol at ftp://ftp.x10.com/pub/manuals/ . I recommend xtc798.pdf and cm11a_protocol.txt as good starting points.
I coded a lot of X10 stuff in the last 7 years. It should not be used for life safety related scenarios.
Daniel
Ah, sew our memories due agree? It is good to get something write, now and uh gain. Eye am pleased two half a gut memory know ant a gen.
(Well, hit past the Smell Czech program).
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