Created Date: April 17,2010

Created by: bcarlton

As you point out, at this point the ability to use pointers is very limited in the Click. In the help file - Reference - Memory Addresses scroll down to the use of Pointers. They can only be used in the Single Copy instruction.

They show the reference is TYPE(DS Register)

Think of the 'pointers ' not as pointers in 'C ' but as array indexes. The 'pointer ' is just a number, not an absolute address. So if you substitute 'array index ' for 'pointer ' in the explanations your thinking may be clearer.

So the 'pointer ' (Click terminology) is loaded not by taking the address of a specific variable but just by being set to the numeric part of the reference. Even then the 'pointer ' could be used to 'point ' to any of the data types. It is just a substitute for the numeric part of a memory reference.

And again, it's ony usable in the Single Copy command.

Created Date: April 17,2010

Created by: milldrone

jnnewton,

I have a hunch that Bernie's reply answered your post to your satisfaction. But if you need more, I have a program that I wrote purely as an exercise. It has not been tested. I do not know if it works. You should be aware that I'm infamous for writing code that does not work until it's tested and modified.

I was hoping to store values in the PLC using a pointer for advancing the memory location to a different location. The drums may be hard for you to understand.

Created Date: April 17,2010

Created by: jnnewton

ok, i am trying to understand how to use pointers in the click software, and need just a couple of examples from someone who knows how c / cpp pointers work. if you could tell me how to do the following things, in the click software, I will need no more help. I have read that only ds (type int) variables can be pointers, so we will use that as my example. i know not everyone here is a c programmer, but i'll try to comment best i can. i am fairly new to the plc game, so i need to explain in c:

int src, dest; //addresses already declared, just need to "nickname "

int *p_src, *p_dest; //declare two pointers (not necessary in click (i think)

//lets say i want to set p_dest (call it ds10) in this case to point to txt1, or src for the example

p_src = &src; //p_src now points to src / txt10 nicknamed src

//lets now say i want p_src to point to txt1 / nicknamed dest

p_dest = &dest; //p_dest now points to dest

*p_src = 7; //txt10 would now hold the value 7

*p_dest = *p_src; //txt1 now holds the value 7

p_src++; //p_src now points to the next adress, in this case txt11

thanks for the help.