Hi,

Is there a way to make a function block with dynamic inputs?

For example:

I want to have n (integer number of tanks) as an input for a function block, other additional inputs should be then equals n number as well as the outputs.

If this is not possible, what are the best options to accomodate this?

Regard

You can't dynamically change the number of inputs on a block, but you can do the following:

Step 1: Define a global user constant, e.g. NUM_TANKS
Step 2 (optional): Define a UDT that collects all inputs for a single tank,
Step 3: Define your inputs in the block interface as "Array[1..NUM_TANKS] of MyUDT" (or as arrays of some other data type if that suits your needs). Collect your inputs in an array and pass the array to your FB.

One downside: you cannot vary NUM_TANKS at runtime.

Alternative solution: Define your inputs in the block interface as "Array[*] of MyUDT" and make use of the UPPER_BOUND and LOWER_BOUND instructions to determine the array limits dynamically.
This is useful if you need multiple instances of the FB in your program with different array limits, as you can't use a user constant for the bounds in that case.

0_Einstein

You can do it the other way, provided you have a maximum number of inputs in mind.  Create all those inputs, with all but the first "dynamic" input configured as an optional input.

Then the block can be expanded to show all available dynamic inputs and you simply provide inputs as required.

It makes the code more difficult because you need to verify every input actually exists before processing.

The UDT method is much more efficient.

inder02

Thanks :)
At least this gives me options

Could you please provide us with a simple example?