Help with Logic for a PLC problem

I have a rudder on a boat, and I need to transmit rudder position through a PLC controlled motorized pot. So my motorized pot must always constantly follow the rudder. How would you structure the ladder logic for that kind of action? Thank you for you advise.

Try using the SCP (Scale with Parameters)
I am assuming that the rudder generates a signal to PLC. Possibly a 4-20 mA signal to analog input card.
You can scale it and send it to an analog output card.

See the sample code below.

This would require an analog input..since you are using a "pot" (hopefu;;y that means potentiometer) then you would use a 0 to 10v scale OR a -5 to +5 scale (which equals 0 to 10v). The details are yours to develop.

You didnt mention WHAT plc so the HOW can be different (but kinda the same) from brand to brand. Is that confusing, you aint seen nothing yet.

Anyway, as an example lets say you have a 10k pot on the rudder and a plc analog input that uses 0-4095..ie 4096 points (zero counts as one). You have to determine a way (with your specific brand of plc) to make 0-2047 equal 0-4.9v and 2048-4095 equal to 5-10v.

I know I aint helping much...to put it as simple as I can you need an analog input card then establish a central point with the point to determine when its moving right or left of center, the pot action will tell it when moving right or left....lets center the 10k pot at 5k and that equal 5 volts...any movement in a direction would increase or decrease the voltage which in turn would change the analog input numbers...ie 2048 would equal 5v therefore if rudder moved I/5 of its travel then the pot would input 4v (approximately) which would give the plc a number of 1638 (actually 1638.4) which in turn tells the plc that it has moved 18 degrees in a left/right/starboard/port direction.

OK IS this clear as mud? Others will clean the mud if you are lucky and PARTICIPATE

KIM, I think you are great. Your advice is right ON in most cases

BUT

You have a tendency of thinking in AB terms. NOT all plcs look, feel or have the same features as AB. AB has commands that are not available in all brand

I say this because AB wasnt mentioned in the original post.

Sorry, I guess I did not look at the problem carefully enough. I assumed it was an Allen Bradley being used, and you should never assume.