[Edited on 31/1/18 by femster87]
Hi all,
Need some advice. I need to test a circuit on a cutting machine. I think the servos have been locked out due to a fault on the light curtains.
These switches. Output 200mA . Is there a way I can get a current generator and inject to make the limits . Sorry this is not my area of expertise
200mA for a sensor seems high, what voltage is it. do you have a photo of the sensor?
10-30v
[Edited on 31/1/18 by femster87]
having done a quick search on elesra, they seem to mostly supply relays.
this would make sense that the output is just a pair of contacts capable of 200mA
Another way of looking at it - how much are the sensors to buy?
Sometimes quicker and easier to replace parts than fiddle about with them.
Average price is £60 quid each and I need 4
Depends if they use both signals coming back from the switch as a negative check or not as to how you could bypass FOR TESTING ONLY. As you say light
"curtain", I'm assuming it's some sort of safety device so shouldn't be bypassed
I'm guessing it's something Japanese as only they tend to use NPN switches? I'm guessing here but that's probably the receiver
from a pair (one sender, and that is the receiver)?
Anyway - wherever that gets wired to, try a link (or any other switch) between the black and blue wires - that will think the thing its plugged into
think that it's now seeing the light generator. If it needs to see the light beam broken, then disconnect the black and connect the white to
blue.
thanks the test is not to run the machine like that. It is more to confirm the fault. The servo drives might be on the blink. I just need to isolate
the fault. I am getting a safety switch error followed by servo timed out. So I need to clear this one first to know how to proceed
[Edited on 1/2/18 by femster87]
Safety Switch error suggests it's not seeing it switch correctly - I'm guessing it's going to be using both signals (to check the
switch is working and connected). If it doesn't see the 2 outputs switch over within a certain time (usually a couple hundred milliseconds), it
should (!) trip out anyway as the system is faulty. I know that doesn't help you at the moment..
Can you get hold of another switch with a changeover contact, such as a limit switch, and wire that in instead? You might be able to simulate it with
an NPN switch such as a proximity sensor as long as it's also 4 wire.
They might be coded switches - and whilst it might be the sender at fault as much as the receiver (which you've added the picture of), they look
to be a special for some CNC kit rather than a generic part off the shelf hence trying to find a direct replacement isn't easy (or cheap).
If they've used Elesta switches, then maybe it's running a Pilz Safety relay but if it's feeding into a bespoke controller, then
there's no real way of knowing how to "bypass" it for testing purposes rather than replacing that switch with one it will think is the
same - or at least acts the same.
That's muddled the water. Can't remember seeing a pilz safety relay in the panel. Will have a look tonight. The white wire is not used .just the black for the output. I don't think they are programmable. Will soon find out. You are right in that it is a through beam sensor. I did not think about the proximity sensor test. They are much cheaper and can prove the circuit is fine or not if I can get one that works in the same way
That is am NPN switch. IIRC that means the 200ma is a current 'sink' to ground,not a supply. if you use the 'output' to earth a
component (relay, bulb etc) that requires less than 200 ma it should work fine..... i think. Unless its broken, in which case it wont work 
Ah - if the white isn't used, then you can wire in a (or 4) Proximity switches and rig something up? 3-wire ones (and makes sure they're
NPN) are readily available - about a fiver on Amazon or eBay for UK supplied ones so next day delivery if you have Prime.
By the sounds of it, it's going to be quite a simplistic safety system then - and you could get by with just linking the black to 0V (blue) to
test the circuits and see if the safety circuit becomes live BUT if it needs a transition (break then make), the proxy switch method would allow you
to knock something up so you have some way of switching it.
quote:
Originally posted by femster87
That's muddled the water. Can't remember seeing a pilz safety relay in the panel. Will have a look tonight.
quote:
Originally posted by femster87
Average price is £60 quid each and I need 4
Thanks alot guys. Will be testing again to when I get in
http://jaxxeninc.com/optosensor
http://jaxxeninc.com/pdfs/optosensors/ElestaOptosensorNewCatalog2013.pdf
the catalogue includes standard wiring for their 4 wire sensors
the reference to pnp and npn indicate that they are a transistorised sensor, (not relay as I suggested earlier)
I think you could safely test them with a 12v battery, and a load (12v 2W bulb)
note if you need to see the infra red transmitter, most mobile phones cameras 'see' in that range, test camera first with a tv remote
elesta closed about 2007
edit, what ss1turbo says makes a lot of sense
[Edited on 1/2/18 by gremlin1234]
You lot never fail to amaze me
quote:
Originally posted by gremlin1234
edit, what ss1turbo says makes a lot of sense
[Edited on 1/2/18 by gremlin1234]
bit of an update. I tested the sensors and there was 24v on the output wire and the input. This was connected to a crystal relay. when i tested the relay, both pins were outputting 24v ( supply to the switch and the connection from switch output. This seems odd
That’s probably because they are NPN - it sinks the return leg on switching. Normal is PNP - when switched it creates the 24V.
quote:
Originally posted by dinosaurjuice
That is am NPN switch. IIRC that means the 200ma is a current 'sink' to ground,not a supply. if you use the 'output' to earth a component (relay, bulb etc) that requires less than 200 ma it should work fine..... i think. Unless its broken, in which case it wont work
quote:
Originally posted by dinosaurjuice
quote:
Originally posted by dinosaurjuice
That is am NPN switch. IIRC that means the 200ma is a current 'sink' to ground,not a supply. if you use the 'output' to earth a component (relay, bulb etc) that requires less than 200 ma it should work fine..... i think. Unless its broken, in which case it wont work
Have you tried this Femi?