PCI 6503 - Interlocking

[IEC]

Hey Everybody,

I have a PCI 6503 DIO card.  I have used labview a pretty hefty amount, but ironically, have never had to use a DAQ card of any sort.  I am building a laser system which has need for several interlocks and I would like to use the pci 6503 to do this (i found it in our lab, that way i don't have to buy anything else). 

Has anyone had any experience using the 6503 or similiar DIO cards to monitor interlocks?

I'm not sure where to start but I think the easiest way is to have the card monitor a 'short' connection somehow.

Any help as to where to start would be greatly appreciated!

Thanks,

Jonathan

[nyc_(is_out_of_here)]

I recently programmed the PCI-6503 to do some simple setting of bits. I used all three ports as outputs. This is a card that will work with either Traditional NI-DAQ or the newer DAQmx.

The one thing I found odd was the picture of the connector in the manual would seem to indicate that pin#1 was upper left corner when looking at the connector as you are looking at the back of the PC, but it isn't. Pin#1 is actually lower right.

http://forums.ni.com/ni/board/message?board.id=70&message.id=4664

[AnalogKid2DigitalMan]

I have indeed used digital inputs to monitor E-STOPS and interlocks for lasers and motion control. A DAQ card cannot monitor a short directly, you need to have a distinct pair of volatge levels that are TTL compatible to detect a change of state. There are various approaches;

If the interlock signals are TTL compatible (0-5V) then you can wire the input direct to the interlock signal and you need to wire the GND reference for the interlock signal to the digital input ground on the DAQ card.

If the signals are not TTL compatible then you can use a resistive voltage divider to bring the level down to 5V and feed it to the digital input. This assumes that the other state of the signal is near 0 volts. You may want to review the voltage ranges for a TTL logic 0 and 1. Again, need a ground connection.

The approach I typically use is to spec all my interlock switches to have a second set of of contacts. I use these exclusively for the interlock monitoring. Have them send 5V to the digital input when interlock is closed and pull the signal down to 0 volts when the interlock switch is open.

Let me know if you need more info.

[IEC]

Ok so I went ahead and got the interlock idea working...

I've used the PCI6503 to send a 5V TTL through a magnetic shorting device... the type of device that you see on home security systems, when the two sides of the sensor are near each other the circuit is shorted out and the PCI6503 detects a 5V signal on one of the inputs. When the sensors are far apart the magnetic link is missing and the circuit is opened (0V) so the PCI6503 detects ground.  I used a very simple VI which will run asynchronously behind all my other VIs and when it registers an interlock-interrupt it will write to a global variable which will then start an immediate shutdown sequence.

Here's a question though...

After all the interlocks are setup I will only be using 6 ports on the 6503. 

Does anyone know of any really neat things I can do with the 6503 so I can use the other ports?  I figure I'll setup an LED status register for some of the ports to show where the system is in the startup, shutdown, etc. sequences... but would like to use this thing for some more functions so that I can really get an indepth feel for this DAQ card.

Thanks for all the help,

Jonathan