Hello professionals. 

 I would like to update my program to be better
 and would be grateful if I could get
 comments / advice. 

 The program is for controlling a bucket elevator for grain.

Operating principle:
 I3 starts the elevator
 I8 ind sensor gives a pulse (rotation monitor)
 Q2 opens the door (linear motor)
 and the grain enters the elevator.
 I6 cap sensor closes the door and after
 a delay the elevator turns off.

I would like to replace the I4 limit switch
 with an AC current transformer (4-20mA)
 that measures the elevator motor current.
 So the door would open optimally.
 (grain types have different weights)
 and if possible the same sensor would 
close the door when there is no more grain (idle operation).

PROBLEM 1 The door should open slowly, 
because the load increases with a delay.
  PROBLEM 2 The idle current is not quite constant.
 The belt extension gives a small current spike 
every revolution. (every 3 seconds) 

 Is my idea doomed? 
 I have LOGO BM and shunt resistor and
 https://www.gavazziautomation.com/en-global/product/E83-2050?cHash=9d1e1183d69c338bb0b1148768112be8 

 Pulse simulation and Message Text is for simulation only.
  I would be grateful if I could know

 if I can succeed with this configuration.

Hello AutoGen,

I have a few questions:

Do you really have a linear motor for the door, or is it more of a drive spindle ? Is this motor directly controlled or does it run via a frequency converter ? (Problem 1)

"I would like to replace the limit switch I4 with an AC converter (4-20 mA) that measures the current of the bucket elevator motor. This will ensure the door opens optimally. (Different types of grain have different weights.)" I can't see the connection between the limit position and the weight. Please explain in more detail what you mean by that.

The no-load current in a bucket elevator can never be completely constant.This is due to the design of the system. Therefore, it is unsuitable as a reference value.

Best regards, Ella_68

(translated with Google)

Hi Ella_68 and thank you very much for your answer.

So the hatch has to be opened much more for oats
 than for wheat, if you want to do it efficiently.
 The hatch has a 500mm actuator motor 24V without 
speed control and now the limit switch allows it
 to be opened about 300mm.

I thought that with current measurement there 
would be no need to adjust the height of
 the limit switch and there would be
 no fear of overload. 
I would estimate that 8 - 9 A would be a good current
 for the job. (Motor maximum 11.5A). 

 If you think the idea is crazy, I can think of
 more opening limit switches.

Thanks again for your help.

Hallo AutoGen,

AutoGen_3987486

I'm still wondering what if, for example,
the current sensor fails and the analog input
does not increase, the door opens to its
extreme position and the elevator overloads
and gets stuck....
This is at least the weakness of my program.