1 Attachment(s)
Need 2nd opinion on Wiring diagram.. proximity - isolation - lpt.
Hello fellow members.
Just want to get a 2nd opinion on this wiring diagram below.
12 proximity sensors going into a 12 channel isolation board at 24v.
Then going out of the isolation board at 5v.
Then going from board directly into an input based LPT port of my cnc controller.
Sensors: NPN, NC, operating at 24v.
Isolator board designed for 24v/in & 5v/out.
LPT is port 5 of a UC300eth controller running at 5v.
Diagram:
Attachment 30299
Yes it would be easier to get a bi-directional bob for it but we're talking about the u.k. here.
You can't get Jack.
(Anyway. The multi isolator boards look neater and are easier to get)
Re: Need 2nd opinion on Wiring diagram.. proximity - isolation - lpt.
Gets my vote, in principle at least. I'd be interested in critiquing component value selection (just look/work around the opto CTR)
Re: Need 2nd opinion on Wiring diagram.. proximity - isolation - lpt.
Quote:
Originally Posted by
Doddy
Gets my vote, in principle at least. I'd be interested in critiquing component value selection (just look/work around the opto CTR)
Hopefully this is relevent.
A quick read of 300eth manual again.
The 5v is a pass through from my seperate psu which is supplying it.
Into the controller from my psu (using a 5v 3A) to power it's logics and passing through to pin 26 for powering additional I/O.
States :Minimum for controller = 500ma. Higher needed for adding extra I/O.
All output pins TTL max 20ma. Inputs TTL 0/5v levels.
Took the 5v in diagram from Pin 26 on port 5 for convenience due to it being right next to opto board in the box layout.
Psu itself is further away.
(Will look at opto model number when it turns up)
I actually already have a UCBB under power from Pin26 on port 1+2 already for axis controls.......
........(16 outputs - 18 inputs - high speed chips - 7HC types or something. Can't read them atm).
So it must have the guts in it to run a bunch of diodes!.
The diodes are actually just to show which port the fault is on. They only light if opto is active.
Re: Need 2nd opinion on Wiring diagram.. proximity - isolation - lpt.
What is the idea behind all those diodes on the inputs and outputs of the opto isolators? Those are just waste of parts. If your proximity sensors are fed with 24V then calculate the opto isolator R-value for that and that's it. No need for any other diodes and resistors.
That is, unless they are LEDs, in which case I would only have them on the outputs (inputs of UC300). I would use very high intensity LEDs which require very low current ( ~1-2mA or less ) for normal conditions. I am a big fan of 100,000 mcd green or blue LEDs and use them even for purposes where high intensity light is not needed because they require such low current for normal conditions that it is almost unbelievable.
https://youtu.be/aB5bX-nn4K4?t=239
Here you can see what I mean. The green LED is driven through a 51k resistor and the blue one via a 6.8k from 12V. Note that the room is very well lit.
1 Attachment(s)
Re: Need 2nd opinion on Wiring diagram.. proximity - isolation - lpt.
Some caution, and breadboarding required here. One problem is we're considering a theoretical model, not an electrical model of the EC300-ETH input circuitry. Once upon a time I sketched this out for this site but cannot find the post now.
It is something like (but not sure how precise, or even accurate this is, or the component values.... and I'm not about to dig out my UC300 to double-check)....
Attachment 30301
The problem is around the 3v3 operation of the internal logic on the EC300, which necessitates the use of the potential divider resistor network shown in the box on the right of the sketch.
This will allow high-intensity LEDs to illuminate even when the input is off (current path through R4/R1/R2).
OP: Just worth breadboarding one channel when you receive the isolator board. Consider your 300ETH-side LED indicators as sacrificial in the overall solution.
Re: Need 2nd opinion on Wiring diagram.. proximity - isolation - lpt.
Quote:
Originally Posted by
Doddy
Some caution, and breadboarding required here. One problem is we're considering a theoretical model, not an electrical model of the EC300-ETH input circuitry. Once upon a time I sketched this out for this site but cannot find the post now.
It is something like (but not sure how precise, or even accurate this is, or the component values.... and I'm not about to dig out my UC300 to double-check)....
Attachment 30301
The problem is around the 3v3 operation of the internal logic on the EC300, which necessitates the use of the potential divider resistor network shown in the box on the right of the sketch.
This will allow high-intensity LEDs to illuminate even when the input is off (current path through R4/R1/R2).
OP: Just worth breadboarding one channel when you receive the isolator board. Consider your 300ETH-side LED indicators as sacrificial in the overall solution.
I am not sure this is right. The UC300 uses 5V logic, not 3.3V. Pin 14 of the HC14 is directly connected to pin 26 of the IDC connector #5 where the 5V output is (I just measured). Why would there be such weird voltage divider on the input? Also, the manual clearly says: "All output pins are TTL level with 0/5Volts output Voltage levels and an absolute maximum of +-20mAmps current per output channel. All inputs are TTL compatible and accept 0/5Volts Voltage levels."
1 Attachment(s)
Re: Need 2nd opinion on Wiring diagram.. proximity - isolation - lpt.
Quote:
Originally Posted by
A_Camera
I am not sure this is right. The UC300 uses 5V logic, not 3.3V. Pin 14 of the HC14 is directly connected to pin 26 of the IDC connector #5 where the 5V output is (I just measured). Why would there be such weird voltage divider on the input? Also, the manual clearly says: "All output pins are TTL level with 0/5Volts output Voltage levels and an absolute maximum of +-20mAmps current per output channel. All inputs are TTL compatible and accept 0/5Volts Voltage levels."
Actually, for once I might agree with you - perhaps a half-arsed memory of mine of an aborted project to spin a replacement motherboard for the UC300 daughterboard with onboard ruggedised interfaces - and it describes the interface between the 5V motherboard and the 3.3V daughter card.
Yes, OP, ignore my previous senile ramblings.
EDIT: That's helped me to find the old project under Eagle, completely irrelevant for this thread, but for closure for myself....
Attachment 30302
That's the equivalent circuit for the daughter-card to motherboard interfaces on the UC300 (in case anyone else wants to ruggedise the UC300)
Re: Need 2nd opinion on Wiring diagram.. proximity - isolation - lpt.
Quote:
Originally Posted by
dazp1976
Hello fellow members.
Just want to get a 2nd opinion on this wiring diagram below.
12 proximity sensors going into a 12 channel isolation board at 24v.
Then going out of the isolation board at 5v.
Then going from board directly into an input based LPT port of my cnc controller.
Sensors: NPN, NC, operating at 24v.
Isolator board designed for 24v/in & 5v/out.
LPT is port 5 of a UC300eth controller running at 5v.
Diagram:
Attachment 30299
Yes it would be easier to get a bi-directional bob for it but we're talking about the u.k. here.
You can't get Jack.
(Anyway. The multi isolator boards look neater and are easier to get)
Finally got round to testing this out. Generic off the shelf isolator board 24v npn/pnp input - 5v npn output.
It works perfectly!!!.
Connected 8 proximity sensors to isolator board (24vin). Connnected isolator (5vout) to port #5 inputs 2-9 on uc300eth directly.
Turned it all on and it all worked as it should. Uccnc showed them trigger in diagnostics page when metal detected, and acted correctly when set up as limit switches on port #5.
Generic board, that includes din rail mountings, less than £20!.
Will be using these on ports #4&5 in the future.
https://m.aliexpress.com/item/400038...Adapt=Pc2Msite
Now to get a 5v to 24v to work on the 4 outputs on those input ports.
