Step 7 using pointers

Hello,

I'm new with siemens step 7 (PLC : S7 300) and i have a question about using pointers.

I have created a 5 DW shift register for an conveyor which is clocked by a puls generated bij the conveyer. At a on a control panel specified starting point (example : bit 80 of 160) i have to make an action.

I want to make a pointer where the initial value is te starting point of the register then add the value specified on the control panel and see if that bit is '1' or '0'.

Can anyone help me with this problem?

I dont know if this is what you are looking for......

//Open db containg databits
OPN DB 1

//Load startingpoint in adressregister1
LAR1 P#DBX 0.0

//Load value of MW0 into accu1 (Integer value from Op)
L MW 0
//Add value from MW0 to adressregister 1
+AR1

//Check if bit is 1
A [AR1,P#0.0]
= M 2.0

If MW 0 in this case contains 8 bit 1.0 in db1 is checked. If mw0 contains 25 bit db1.dbx3.1 is checked.

Thanks Bratt after some modifications i think it will work.

We'll see at next weeks tests anyway.

pointer

there are many solutions ....



L MW 10 // your bit index value 0..159
LAR1

OPN DB xx
A DBX[AR1,P#4.0] // assuming your DW's start at 4.0
= M10.0


hope this helps you

Hello! have a related question about pointers on shift register applications..how do i write the value of a particular bit say M0.0 in the shift register(5 DW )using pointers and read its value after say bit 80?

Try not to resurrect all old threads!