After looking on the forum I see that I need to give the k8055 addition power for the digital outs and the pwm outs to work.
my question is:
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.
A 2nd question is:
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?
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.
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?
[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]
I think this is what I am asking (send 1 and it is open no power clamp does not have connection - I was thinking output line is grounded so clamp does complete the circuit. as that is what seems to happen…but I guess I have it backwards?
I just posted a huge reply of getting TTL in the thread
“newbe] K8055: connect relay”
and its works but is different then yours and requires no extra reister just grabbing the 5V off the output off the PIC.
I am wondering how your suggested way for TTL would work for all 8 lines? so its seems you just create a seperate board with resistors on it and connect the K8055’s 5V to it …not sure on wiring of all that?..It seems that off is on in this example which is fine, but when you want to power your relay board with K8055 5V+ then the switches would cut it off and on? of course you do have two 5V+ lines on the board, but thats it…you could have a TTL and a line to use K8055 5V for some power. In readying though, is your example for only 1 line?
I’ll have to look at it more to see if there might be a way to make an expansion board that uses the K8055’s 5V+ and then allows TTL from the outputs so you can switch between open collector and TTL. Maybe something like this guy for a 7 line switcher…(or a mod of it?)