Home Switch Problem

[Kev2960]

It drops to about 2.8 - 3.0v

[john swift]

Hi Kev

the voltage drop on the printer port pin to 2.8 - 3V is too small

you should have it dropping to near 0V when the switch closes

assuming the opto-isolators LED is powered from +5V
this is what I'd expect for the breakout boards limit switch input

corrected diagram


(arrow pointed to the wrong end of the 1K resistor on the original diagram)

John

[Kev2960]

Sorry my mistake, misunderstood what you said the voltage when the switch is presses is zero volts

[john swift]

Hi Kev

do you use two seperate power supplies for the breakout board ?

I have made a correction to the diagram in post 12
this is how I expect the breakout boards input circuit to be



from the limited detail in the photo of the breakout board the two regulator IC's appear to be LM317 plus resistors = 5V regulator for the 74HC245D IC's

LM2576S switching regulator = 10V regulator for the analogue VFD drive

John

[Kev2960]

Hi John. There is a 24v which I think is for fan and 5v which is for the drivers. I've been playing around with it all night but still no joy. Just a silly question but should the switches be carrying voltage ? Because mine aren't

[m_c]

There should be voltage at the switch, which makes me think you've not got the board powered correctly.

What power supply do you have connected to the board?
And do you have a link to any kind of manual for the board?

[john swift]

yes ,
you should measure a voltage across an open limit switch wires

about 4V if the input circuit has a 5V supply



John

PS
a photo of the breakout boards supply terminals will be usefull wth
a diagram of the breakout boards supply connections

[Kev2960]

Would it be best to get another bob rather than messing around with this one, which doesn't seem to be much good

[Clive S]

Would it be best to get another bob rather than messing around with this one, which doesn't seem to be much good

As have been said do you have the manual. Also doe this bob require two power supplies I say this because I do have a Chinese one that is powered by usb BUT the inputs won't work unless the other power supply (12-24V) is connected as the bob gives out the 0-10V for speed ref. Just a thought.

[Kev2960]

I don't have a manual for the bob just for the machine itself. ive enclosed some photo's of the bob and the main board