Hi,

First of all sorry for the long query.

I am working on a application related to stone processing. The machine has an SLAB (stone) entry point where number of limit switches are mounted (attached sketch). The entry point has a center limit switch (for e.g. 11th number in the attached sketch) which divide the complete machine bed into LEFT side and RIGHT side. Each limit switch is placed at 75mm distance from other one. Based on the entry point of the stone slab, limit switches get activate. For e.g. position on the stone slab is from limit switch 5 to 15. So the stone slab size is identified is 10 X 75 = 750mm and then I take care of motion from left to right based on encoder feedback.

So far it is working fine but issue is I need to changes this logic every time as the limit switches keep changing based on the machine it varies from 20 to 40. Now I like to create this logic to adopt this dynamic situation. Following is my thought:

Entry fields on HMI:Total number of limit switches, Center limit switch and distance between limit switches. All are INT data type

PLC Side Logic: Created a FB with above HMI fields and reading sensors input ID0 (32 input so far). So far, I am able to read the correct limit switches using dword to bool logic. A respective bit is assigned to each limit switch (bit 1 to bit 32 for 32 sensors) but not getting perfect solution further.

Further, I need to identify center limit switch entered from HMI. Based on that, divide the stone slab bed into LEFT and RIGHT side, count the sensor to the total number of sensors to the LEFT and RIGHT side OR identify most left side activated limit switch and most right side activated limit switch (this will give the total stone slab width).

Please suggest the way forward. Thanks.

Next step could be mapping inputs to array of bools. With indexing the array and some arithmetic you could find all info you need.

But the very first step is to read this post.

An alternate idea..
Do an in-motion size measurement.

S7-1200: Application Examples for High-Speed Counters (HSC)
( Example 2 )

How do you realize Length and Speed Measurement
using High-Speed Counters of SIMATIC S7-1200?

jacek d

Next step could be mapping inputs to array of bools. With indexing the array and some arithmetic you could find all info you need.

But the very first step is to read this post.

 Hi,

Thanks for your idea and also for sharing important information about template.