03-06-2006 07:09 AM
03-06-2006 10:03 AM
Hi Mic_Scale:
The 2062 is a relay card, you will have to supply a voltage to the COM pole of the relay you are using and the monitor the output from the NO or NC (normally open or closed) relay contact. The 6025 should be able to toggle an ouput on and off at a fairy fast rate through software timing. It is the relay that will limit your switching speed, 30 to 60 times a second, I suspsect. I would suggest you read the section of the manual covering the 2062.
I did not get a chance to look at your vi
03-06-2006 03:35 PM
03-06-2006 03:53 PM
Yes, that would explain your results on the oscope. Think of the relay and it's 3 terminals as a switch which has a normally closed contact and a normally open contact. The COM terminal is common to the other two. When the output is commanded OFF, you will have a closed switch between the COM and the NC terminals. When the output on ON, you will have a closed switch between the COM and NO terrminals. You have to supply the voltage you want switched and typically connect it to the COM terminal. I suggest trying it out with the scope to experience it first hand. Due to mechanical interia, mechanical relays of this sort can only switch so fast. Not possible to get anywhere near 100KHz (maybe 100Hz)
The digital outputs on the 6025 are not contolled by any on-board timer, so the only option to use those is using software timing in a while or for loop. But loops can only execute so fast, this may get you inot the KHz range. But Windoze timing uncertanties will probably yield you a frequency that is unstable.
I would suggest using one of the 2 built in timer/counters on the 6025 to generate a very accurate and stable pulse train. I have used this card in the past to control a high power laser. For it I used and opto-isolator chip between the DAQ card and the laser in case the laser power supply failed. Worked like a charm. I don't believe the counter signals get routed through to yhe 2062, you will have to get the manuals out and figure which pins the signals come out of. There are shipping examples within LV to generate pulse trains with the 6025.
Good Luck, let us know if you need futher help.
AK2DM
03-07-2006 10:36 AM
03-07-2006 10:47 AM
Almost any garden variety opto will do, I have used these Avago (was an Agilent part that used to be an HP part) optos before with no problems.
http://www.avagotech.com/pc/downloadDocument.do?id=4829
Please refer to the above datasheet/ app notes, for reference, I used 6.2K/22pF on input pin 2 and the 1K internal resistor on the ouput side, pins 6/7. You may want to adjust for your specifics as needed and view output waveform with a scope. Thae 6025 counter was able to directly drive the diode with the 6.2k in series. I used an external 5V supply on the output side to provide isolation.