The current is what I'm focusing on keeping to a minimum. I already have the ULN2003 for the 5V to 24V. Now I need the 24V-5V. I've pretty much figured the zener route as the most simpe and cost effective way to do this. Thanks for the ideas Ross. I think I'll try my hand at PCB's and make my own. If I had the time and wasn't learning so many other things, I have an open source DF1 driver coded in VB. I could develop a custom app to referee between the DF1 and the W/C. I just lack the experience with VB and the time to learn it. I want a couple of your boards but the shipping would be more than the boards.
I'm going to use 8 bit parallel both ways so timing won't be an issue. Each unit will send a request and the other will respond with the requested info.
My current output from the 24vdc card isn't a big issue, I just haven't found an opto coupler and example circuit that handles 24vdc in and 5 out. Although I suppose I could use the zener and resistor on the 24vdc, it just adds a lot of baggage.
I'm going to use 8 bit parallel both ways so timing won't be an issue. Each unit will send a request and the other will respond with the requested info.
My current output from the 24vdc card isn't a big issue, I just haven't found an opto coupler and example circuit that handles 24vdc in and 5 out. Although I suppose I could use the zener and resistor on the 24vdc, it just adds a lot of baggage.