pulse generator(like help)

[jesseyma07]

I am a recent tech school grad and am trying to build a pulse generator for final testing of my company`s product. The pulse generator would simulate a flywheel which is supplied by the customer at their site so you see my need for this project. I have been thinking about a simple 555 timer circuit connected to a transistor(if necessary) switching a relay, passing 24v to the input of a plc. the 24v is already supplied by a power supply. Any ideas? Has anyone worked with this circuit? It does`nt have to be the said circuit, just an on, off, on, off.

 

[kchriste]

I would assume the "flywheel" sensor outputs a square wave that swings from 0V to 24V? At what frequency or interval does it do this?

 

[Boncuk]

Here is a simple timer circuit. Its frequency is ~1Hz. You can change according to the data sheet formulas.

You can't switch 24V using an NE555 timer IC. Its maximum supply voltage is 16V. However if you want to activate a 24V-relay connect an NPN-transistor with a 10K base resistor to the IC output. Connect 24V to the relay and the other side to the collector. The emitter connects directly to ground. Don't forget to use a free wheeling diode in parallel with the relay coil (cathode connected to 24V). Depending on the relay the transistor would live long or may be fried right away.

Boncuk

 

[jesseyma07]

Thank you.

Been very helpful. I remember this circuit from one my first labs in school. May go with a relay that has pulse circuitry combied in one package.