Hi, some answers to your questions I hope:
[quote=“kyleg”]Do I have to use a external power supply or can I just connect the k8055 5V+ to clamp with a jumper wire since K8055 supplies its own 5V (enough for TTL signal anyway)…just want 5V TTL for the digital outs.
[color=red]A connection to “Clamp” is only needed if you are going to work with inductive loads (as e.g. relays).
So, it you want a TTL output, just connect a resistor (e.g. 1K) between the +5V of the K8055 board and the wanted digital output.[/color]
After looking at the diagram I am still confused that once I do hook up some voltage to “clamp”, for “open collector method” that there is some confusion as to what is actually going to come out of the digital output?
[color=red]If you send a “0” to the output, then the output pin will be pulled (hard, very small resistance) to GND, if you send a “1” to the output then the output pin is “open” (not connected). In the latter case of course the pin can be pulled high via a resistor that you maybe have added between the board +5V and the pin (see comment on your first question).[/color]
Is is ground? because in the mannual page 19, it shows that the 5V+ that goes to a relay’s Normally open contact is to come from clamp line.
[color=red]Forget about the clamp line, it is only for inductive loads (to prevent excessive induction voltages on the output pins). It does not deliver any voltage/current, it only protects the output IC.[/color]
Is this to mean that initially the digital out is on and you turn it off (pull it to ground) when you send a digital output?
[color=red]I am not sure what the question here exactly is, but perhaps it is already answered above.
[/quote][/color]