Encoder Position Step 7

[DNort]

Hi I am trying to control the position of an encoder using step 7.

I want the position to change when the set point demands it so if position 1 is 10 and position 2 is -10 this would activate a change? I tried using a comparator block but if the tird position is -20 this activates a change again so the motor drives forward when it should be in reverse.

Any help would be greatly appreciated.

 

[waross]

First let's forget the encoder for awhile and work on your question asking skills.
Your question, as asked is almost completely unanswerable.
Possibly if you described your application, and the type of encoder you are using. A description of the process and even a manufacturer and part number for the encoder would be great.
Does your encoder use a base ten output code or a binary code? Switch-tail ring encoding or a grey code? Some esoteric OEM code?
going from +10 to -20 from position 1 to 2, maybe non of the above?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[DNort]

first time user here so go easy on me.

The encoder is an siemens incremental encoder but it is the PLC program that is the problem however I think I have it sorted now.

I will know for sure tomorrow when I return to my PLC however my SFC program is press start button motor comes on at set speed no.1 and drives to position set point 1 then stops and holds for a set time. Then starts again at speed set point number 2 and drives to position number 2. When reaches position set point 2 it stops and holds 5 seconds then starts again at speed set point no.3 and runs to final position set point (usually zero) ie back to start.

My problems so far have been changing direction (but Im hoping a move function will resolve this) also I need to simulate faults into the program which Im struggling with??

Help here would be great.

Hope everything is clear now.

PLC = Siemens Step 7
Encoder = Siemens Incremental
Motor = mini motor
VSD = Siemens Micromaster 410