Simple push button speed steps

Looking for some help ! I need to change an inverters frequency using two speed steps. The operator uses a momentary push button. So first press speed 1 second press speed 2. I need to do this using relays at the moment. Can anyone help with a Simple line drawing ?
Thanks in advance

Is that physical relays, or are you programming this in a PLC?

Also, how does it return to speed "0" when the operator wants it to stop?

If you are just using 2 presets, i think it would be a bit easier to use a 2-position maintained selector or maintained pushbutton. You wouldn't need relays at all. If you prefer momentary with relay, there are latching relays that you can get.

IF we have the push-button as an input to the PLC....

IF the PLC controls two relays as outputs for the inverter speed...

THEN we are only talking about the push-button acting as a "toggle" between the two speeds, and there are a multitude of ways to do this (my favourite uses a counter, bit 0 will always toggle).

AND we need to consider the "starting" speed if the PLC and/or the machine goes off during the process or cycle. It may be that the machine cannot start-up at the higher speed, so any "toggle" may need to be preconditioned.

More detail on your application is needed to make a better assessment.

At the moment it is a 240v relay system. I am progressively going to change it to PLC

Machine is stopped via a stop button

So you need to consider how it is restarted - i.e Speed 1 or Speed 2 ?

My goto "toggle" using a counter is simple, the input just uses a CTU on a counter, and will work forever. Bit 0 of the counter accumulator is the bit that toggles, always, every time, and survives a PLC restart. If you need it pre-conditioned at a process/machine startup, then code it, if not, leave it alone.

daba said:

So you need to consider how it is restarted - i.e Speed 1 or Speed 2 ?

My goto "toggle" using a counter is simple, the input just uses a CTU on a counter, and will work forever. Bit 0 of the counter accumulator is the bit that toggles, always, every time, and survives a PLC restart. If you need it pre-conditioned at a process/machine startup, then code it, if not, leave it alone.

Click to expand...

Thanks that sounds simple. I will interface with a couple of relays.