The problems with my DAQ never seem to end.
I've got an Apex Stratus X ND ADC and an RTD DM6620 DAC in a PC104 system. The DAC creates a 15kHz 1000-step triangle wave that provides modulation to an RF generator in an NMR system. The NMR signal goes through an amplifier, and then to the ADC...
itsmoked: Thanks for the suggestion. I have programmed Atmel AVR's before, and even considered using one in this system. It would be very elegant, which I would love. However, there are a few concerns keeping me back. One is the ease of making changes in the future. I won't always be around, so...
itsmoked: Thanks for all the info.
I've now got counter 1's GATE pulsed low right after I write the new count value.
My meter-counter seems like it might be a little flaky, so now I'm using another 8254 on the DAC card which counts the pulses, and an ADC (which also has an 8254) being...
felixc: I'm using a 25MHz counter (nuclear equipment) to count the pulses and a digital o scope. With and without the feedback counter 0 produces the expected frequency correctly.
designchain: It may be ancient, but it seems to work very well for my purposes, except for the current problem...
Thanks itsmoked, not solved yet. I thought it might be a problem with speed, but it doesn't matter whether I have the first timer going at 15kHz, 1kHz, or 1MHz.
I've made some headway. I've now got it so that it reliably spits out pulses in multiples of 1 000, just not the number I want, i.e. I say 200 000, but i get between 150 000 and 195 000. So it seems like counter 2 is being decremented too quickly.
I've got an 8254 timer/counter chip that is part of a DAQ system.
What I want to do is generate a 15kHz signal, but have it put out only a very precise number of pulses, in a range from 100,000 to 2,000,000. However, I am getting a wide range of pulses, so when I ask for 200,000, instead I get...
