Hello ,

I am using an encoder counts to kick an item on the belt.  The distance from the kick-off and the sensor is 400mm. And I know each encoder pulse will cover the distance around 2mm . From that I can easily tell that it will take 200 pulses until the item will get kick off. But my question is how to program that? Have an interrupt where as soon as the sensor is true, count till 200 and then kick the item? If yes then how can i do that?

Thank you and have an wonderful day!

Hi,

A sample published in this topic:

Sample Program: S7-1200 High Speed Counter (HSC)

I hope I could help!

MicroMan

Hi,

A sample published in this topic:

Sample Program: S7-1200 High Speed Counter (HSC)

I hope I could help!

Thanks for the help! I have seen this before, and I know how to set it up. The only thing I am confused is,  the HSC trigger should start after the part hits the sensor, and count till 200 and then kick the part. I know how to reset it, but I am little confused on how to start the HSC as soon as the sensor becomes on? I don't want my HSC to be on every time, it should only start when my part is in front of sensor! 

 Help me with this?

Thanks in advance! 

the_learner99

 I don't want my HSC to be on every time, it should only start when my part is in front of sensor! 

A suggestion..
Change your thinking about the problem.
Rather ask what you should program so that the HSC can continue counting without stopping.

Target position := Reading now + Travel distance

In your previous posting you asked about arrays.
Arrays can be used here too to store multiple (perhaps 4?) target positions.

w

William_B

the_learner99

 I don't want my HSC to be on every time, it should only start when my part is in front of sensor! 

A suggestion..
Change your thinking about the problem.
Rather ask what you should program so that the HSC can continue counting without stopping.

Target position := Reading now + Travel distance

In your previous posting you asked about arrays.
Arrays can be used here too to store multiple (perhaps 4?) target positions.

w

 Thanks for the reply!

I see what you're saying. And I like the idea of "Target position := Reading now + Travel distance" . I don't think I need to store any target positions, because there will be only one part between the sensor and the kick-off at any given time (But there will be multiple parts on the belt at the same time). Let me try and see if it works, at least what I am trying to do and will get back!

William_B

the_learner99

 I don't want my HSC to be on every time, it should only start when my part is in front of sensor! 

A suggestion..
Change your thinking about the problem.
Rather ask what you should program so that the HSC can continue counting without stopping.

Target position := Reading now + Travel distance

In your previous posting you asked about arrays.
Arrays can be used here too to store multiple (perhaps 4?) target positions.

w

A quick question, I am trying to use same input for two different HSC for different purpose. One for calculating speed and the other for describe in this post. But its giving me comping error. Is there any way you can do this? Have same inputs for different HSC?

the_learner99

A quick question, I am trying to use same input for two different HSC for different purpose. One for calculating speed and the other for describe in this post. But its giving me comping error. Is there any way you can do this? Have same inputs for different HSC?

The HSCs are linked to specific inputs. You cannot have the inputs overlap for both HSCs. However.. there is nothing that stops you from wiring the same "sensor" to two different inputs.

For example.. (allowed)
A single pulse encoder is connected to I0.0 and I0.1 (parallel). HSC #1 is configured in frequency mode monitoring I0.0. HSC #2 is configured in counting mode monitoring I0.1.

What is not allowed is having HSC #1 and HSC #2 both monitor I0.0.

Make sense?

William_B

Target position := Reading now + Travel distance

[Warning]

1.
You first instinct may be to make the compare function..
"Reading now"
    --| == |--
"Target position"

The trouble is that your encoder may be faster than your scan cycle which will give you problems as the     --| == |-- opportunity may be missed.

2.
A better option (not 100% !!) will be to do..
"Reading now"
    --| >= |--
"Target position"

The problem with that option is that the "Reading now" might have a {fold over} event where "Reading now" will become negative. This {fold over} is a property of INTEGER numbers whereby if you add 1 to the biggest +number it will become negative.

Try this on Windows calculator...
* WIN + R
* calc                       ..... call up calculator
* ALT-3 (View > Programmer mode)
* Set (left) to HEX and DWORD
* Fill the number (in hex)          7FFF FFFF  (hex)
* Change on the left to to decimal (DEC) notation
* See the number 2 147 483 647? - biggest possible DINT
* Back to HEX notation.
* Add 1
* The number is.. 8000 0000 (hex)
* Change to decimal (DEC).... -2 147 483 648 !!
* That is the {fold over}.. the biggest negative number.

3.
To fight the {fold over}  ->
"Distance Left Over" := "Reading now" - "Target position"

"Distance Left Over"       "Distance Left Over"
-------| >= |--------------------------| < |--------------- . . . .
       DINT#0                          DINT#100
 (zero & DINT value)        (window for action)

Does this help?
w