I know I am not looping this right!?!

davatv223 · Jul 16, 2014

Newbie here Trying to do ST in RSlogix5000. I am wondering what I am doing wrong

I want to loop through the array and see if the name exists. Any help is appreciated.

for i := 0 to maxNames - 1 do
if Name<> ListofNamesArray then
NameIsListed :=1;
else
NameIsListed :=0;;
end_if;
end_for;

HJTRBO · Jul 16, 2014

I don't know anything on the syntax of structured text in Logix but you need increment your pointer by 1 after the end if statement.

for i := 0 to maxNames - 1 do
if Name<> ListofNamesArray then
NameIsListed :=1;
else
NameIsListed :=0;;
end_if;
i := i+1
end_for;

davatv223 · Jul 16, 2014

you're right, I forgot to add that in. My original code does have that thought.

HJTRBO said:
I don't know anything on the syntax of structured text in Logix but you need increment your pointer by 1 after the end if statement.

for i := 0 to maxNames - 1 do
if Name<> ListofNamesArray then
NameIsListed :=1;
else
NameIsListed :=0;;
end_if;
i := i+1
end_for;

HJTRBO · Jul 16, 2014

OK, so you have checked the basics?
Tag data types are correct? A valid value in "maxNames". Are you calling the routine correctly from the parent routine? Have you tried using true and false to replace the 1 and 0 values?
Again, I know nothing of ST. Someone will be along soon that can help better...

davatv223 · Jul 16, 2014

In the Rockwell manual they have this:

SIZE(Inventory,0,Inventory_Items);
For position:=0 to Inventory_Items - 1 do
If Barcode = Inventory[position].ID then
Quantity := Inventory[position].Qty;
Exit;
End_if;
End_for

davatv223 · Jul 16, 2014

Where Size is an UDT which I am not using , I think this maybe my issue. I am going to read up on UDT's

HJTRBO · Jul 16, 2014

I found your manual. Using UDT's won't help. You don't need to manually increment the loop. It will do that for you. Sorry I can't help you anymore than I have tried.

davatv223 · Jul 16, 2014

no worries, I'll keep on chiggin along. Thanks though

HJTRBO said:
I found your manual. Using UDT's won't help. You don't need to manually increment the loop. It will do that for you. Sorry I can't help you anymore than I have tried.

JerryH · Jul 16, 2014

Never done ST but it seems your loop will check all Names in ListofNamesArry. So if it does find a match part way through and set NameIsListed to 0 then the next name in the array it checks that does not match will change NameIsListed to 1. Unless the Name your looking for is the last one in the array I don't think this will work.

Try something like this:
NameIsListed :=1;
for i := 0 to maxNames - 1 do
if Name= ListofNamesArray then NameIsListed :=0;
end_for;

Another variation would be to exit the loop after finding a match. No sense in continuing to loop and check if you already know the name is in the array.

Jerry

Peter Nachtwey · Jul 16, 2014

davatv223 said:
Newbie here Trying to do ST in RSlogix5000. I am wondering what I am doing wrong

I want to loop through the array and see if the name exists. Any help is appreciated.

Code:

for i := 0 to maxNames - 1 do if Name<> ListofNamesArray[i] then NameIsListed :=1; else NameIsListed :=0;; end_if; end_for;

That code looks syntactically correct.
What do you think is wrong?
BTW, FOR loops automatically adds 1 to I. The i:=i+1; is not required or right.

You can pretty print your code in a post by inclosing it in code blocks similar to quote blocks.

As noted above, if you are only searching for a match then I would use a BREAK; to stop the loop from searching further after a match is found.

benaiahhenry · Jul 16, 2014

davatv223 said:
Newbie here Trying to do ST in RSlogix5000. I am wondering what I am doing wrong

I want to loop through the array and see if the name exists. Any help is appreciated.

Code:

for i := 0 to maxNames - 1 do if Name<> ListofNamesArray[i] then NameIsListed :=1; else NameIsListed :=0;; end_if; end_for;

I think that NameIsListed will only be true after your for loop if the name you are looking for is the last name in the array. Otherwise NameIsListed will only be true for one iteration of the for loop. If you put do as Jerry & Peter suggested and add a "break;" after the "NamesIsListed := 1;" I think it should work.

danatomega · Jul 16, 2014

As Davatv223 indicated in his posted code:

SIZE(Inventory,0,Inventory_Items);
For position:=0 to Inventory_Items - 1 do
If Barcode = Inventory[position].ID then
Quantity := Inventory[position].Qty;
Exit;
End_if;
End_for

the EXIT or Break is going to be needed!

kamenges · Jul 16, 2014

JerryH has the right idea, but I would do it in the opposite direction. This issue is you don't want the 'else' case to mess with you. So don't use it. Initialize NameIsListed to whatever value is the "not found" value before the FOR loop. Inside the FOR loop only set NameIsListed if the name is found. Since you were initialized for the not found case prior to the FOR loop you don't need to explicitly set the not found case after every compare.

Exiting the loop after the first occurrence of a find is a good idea from a code efficiency standpoint but it shouldn't be required for the code to work.

Keith

davatv223 · Jul 16, 2014

Nice input Guys!!! I will try it soon and post up the results.

davatv223 · Jul 16, 2014

Got it working. Here it is. Thanks for the help

Code:

NameisListed :=0;
NameisNotListed :=0;

for i := 0 to maxNames - 1 do 
if currentName<> ApprovedNames_Array[i] then
NameisNotListed :=1;
NameisListed :=0;
else
NameisNotListed :=0;
NameisListed :=1;
exit;
end_if;
end_for;

davatv223 said:
Nice input Guys!!! I will try it soon and post up the results.

I know I am not looping this right!?!

davatv223

Member

HJTRBO

Member

davatv223

Member

HJTRBO

Member

davatv223

Member

davatv223

Member

HJTRBO

Member

davatv223

Member

JerryH

Member

Peter Nachtwey

Member

benaiahhenry

Lifetime Supporting Member

danatomega

Lifetime Supporting Member

kamenges

Member

davatv223

Member

davatv223

Member

Similar Topics