Micrlogix1000

Is it possible to control two motors (pumps) with only one float switch without using latch relays?. I'm using micrologix 1000.
Motor 1 turns on when the float switch closes, when the float switch opens the motor stops. When the same float switch closes again, motor 2 turns on. When the same float switch opens again, motor 2 stops. This system repeats as necessary.
Any help will be appreciated.
Thanks.

Jose.

Greetings Jose,

Yes, it is possible. What you are asking about is called a pump alternator, and it is very common. One easy way to implement a two pump alterantor is with a flip flop. You can search the forum for "flip flop" or "toggle" more information about flip flops, the subject has been addressed ad nauseum. Here is one simple way to do it with a flip flop. Rungs 000 and 001 implement the flip flop, and rungs 002 and 003 control the pump based on the state of the flip flop bit.




If you anticipate that you will some day use more than two pumps then you may want to consider a more elaborate scheme. Search the forum for the keywords +pump +alternator.

Why such dislike for latches?

Be aware that Alaric's programm has no anti-dither provisions (not sure about the term, correct me if it's wrong).
Hence waves in the liquid can repeatedly alter the pumps during short period of time.

Sergei Troizky said:

Why such dislike for latches?

Click to expand...

Homework??