Hi A question for those used to dealing with plc's and the like
Repairing a machine for a friend of mine, simplist of designs
you press a pedal,which in turn resets the counter module which in turn disengages a cluch mechanism that drives a flywheel
there are a number of holes in the flywheel and an optical sensor that is mounted across it connects to the counter
when the preset count is reached the clutch re-engages and the drive stops till you press the pedal again thats it
this is the counter module
View media item 28335and this is the optical sensor conected to it
View media item 28336
the manufacturer of the module (that he wants to keep because of its simplicity) and sensor went out of business years ago so I've ordered a 3 wire npn optical sensor that I thought would work
thing is I think In my haste I've made an error
I went and stripped the sensor out of the machine this weekend in readiness and found that its actually a 2wire sensor of sorts not 3
if you look at the connection diagram above, the light emiter part of the sensor connects to term 5 +com and term 4 - and the sensor part connects to term 5 +com and term 6 -
now I know that the diagram clearly shows the sensor as a npn type (arrow pointing out and + com) but that is a 2 wire sensor
Ive connected the unit up without the sensor connected and tried shorting terms 4 and 6 which is the the negative and input which does nothing but shorting 5(+com) and 6 (input) and the counter counts which tells me I need a pnp type sensor or am I missing something?
got to say if it hadn't been for the drawing of the transitor on the base showing npn then I would have did the test above and ordered pnp but thats got me confused!
Repairing a machine for a friend of mine, simplist of designs
you press a pedal,which in turn resets the counter module which in turn disengages a cluch mechanism that drives a flywheel
there are a number of holes in the flywheel and an optical sensor that is mounted across it connects to the counter
when the preset count is reached the clutch re-engages and the drive stops till you press the pedal again thats it
this is the counter module
View media item 28335and this is the optical sensor conected to it
View media item 28336
the manufacturer of the module (that he wants to keep because of its simplicity) and sensor went out of business years ago so I've ordered a 3 wire npn optical sensor that I thought would work
thing is I think In my haste I've made an error
I went and stripped the sensor out of the machine this weekend in readiness and found that its actually a 2wire sensor of sorts not 3
if you look at the connection diagram above, the light emiter part of the sensor connects to term 5 +com and term 4 - and the sensor part connects to term 5 +com and term 6 -
now I know that the diagram clearly shows the sensor as a npn type (arrow pointing out and + com) but that is a 2 wire sensor
Ive connected the unit up without the sensor connected and tried shorting terms 4 and 6 which is the the negative and input which does nothing but shorting 5(+com) and 6 (input) and the counter counts which tells me I need a pnp type sensor or am I missing something?
got to say if it hadn't been for the drawing of the transitor on the base showing npn then I would have did the test above and ordered pnp but thats got me confused!