Connecting THC proma to AXBBE isolated input

[Arne9999]

I'm trying to figure out how to connect the UP, DOWN, and ARC signals to the isolated inputs of the AXBB-E controller (I'm using UCCNC software, by the way).

According to the manual, the COM should be connected to the negative DC supply, which is straightforward.

For instance, the UP signal would go to the 1+ terminal on the isolated input, and the 1- would connect to the COM.

When the THC relay for UP is activated, UP and COM are shorted, and the input on the AXBB-E registers a defined low (0V). However, when the relay is open, the 1+ terminal becomes undefined—it's left floating, which is not ideal.

I'm considering adding a pull-up to the 1+ terminal using a 24V source through a 10k resistor. But since the manual doesn't address this scenario, I'm hesitant to try without further advice.

[cncdrive]

The input is not "floating", it is an optocoupler input, so it is not a problem if the relay leaves it open.

[Arne9999]

OK so you mean that I should just connect the 1+ to the UP and COM to 1-??

Tis is what I did at first but it does not work. I run a test with the THC and the Z dont move and in UCCNC i don see any activity on the pins. If I measure on the UP to COM output on the THC = measure 0V and like some ranom 0.xx V when open

But what happens when the pin is left open you mean? What will the signal to UCCNC be then?

[cncdrive]

When the input left open then the input is in it's inactive state and when the input is active then it is in it's active state.
So, the virtual input LED should change state.

[Arne9999]

ok but it does not change state.

I still dont understand that 0V and "open" is detected as a change of state. The AXBB manual says


"Port#2 contains 6 isolated inputs. These inputs are built with high speed 10Mbit/sec
optocouplers and both the anode and cathode side connections are wired out making it
possible to interface NPN, PNP and push pull sensors as well as switches and pushbuttons.
There is a serial 2.2kOhm resistor on each inputs which limits the current into the
optocoupler making the optocoupler to function between 10 and 30Volts input voltage
level"

so does that not mean that I need a voltage in the range 10- 30V on the 1+ pin in order to change the state ?? Sorry if Im asking basic stuff but I dont understad

[cncdrive]

Yes, ideally you need 10-30Volts on the input- to activate the input while you have to connect the ground on the input- pin.
This is because the input is an optocoupler, this means that inside the AXBB-E input there is a LED + a series resistor between the input+ and input-.
When you connecting voltage between the input+ and input- then the LED inside the optocoupler lights up and it drives a phototransistor and it's output is connected to the microcontroller of the AXBB-E.

This How optocouplers work video might help you to understand: https://www.youtube.com/watch?v=7a8HRz2 ... plications

[cncdrive]

Yes, ideally you need 10-30Volts on the input+ to activate the input while you have to connect the ground on the input- pin.
This is because the input is an optocoupler, this means that inside the AXBB-E input there is a LED + a series resistor between the input+ and input-.
When you connecting voltage between the input+ and input- then the LED inside the optocoupler lights up and it drives a phototransistor and it's output is connected to the microcontroller of the AXBB-E.

This How optocouplers work video might help you to understand:
https://youtu.be/7a8HRz29qOE

[Arne9999]

Ok... so how could the Led be active when no supply is fed to the 1+ pin>?

now its "0" or "open"

If I put a 24V on the input with a 10k resistor it wold be 0 or 24V which makes much more sense.

[cncdrive]

If you connect 24Volts to input+ and 0Volts to input- then the input is active.
If you don't connect 24Volts to input+ and/or 0Volts to input- then the input is inactive.

[Arne9999]

Yes this is what I was saying from the beginning.

I need to feed 1+ with a defined positive voltage, like 24V or 0V

Just connecting the UP to 1+ and COM tom 1- will just result in 0 when the UP is active and when the UP relay is open the 1+ will be left undefined/floating Alternative 1 in my nice figure below.

Very strange that the manual does not say anything like this...thats why i dont dare to do it and suspect that im missing something....

If I connect 24V to a 2.2k resistor and then to the 1+ the input will get 12V when the UP relay is turned off. But the UP terminal will be getting +12V when the UP is off so I hope that is OK for the porma.