A CPU 315-2 PN/DP with 6ES7315-2EH14-0AB0 on the label maps to a CPU 1515-2 PN, 6ES7515-2AM01-0AB0, in the Siemens migration guide’s CPU table, and the S7-1500 migration does not happen in one move. It happens in two, the second of which is a right-click on the old CPU in the device view called Migrate to … Read more
A DINT stops at 2147483647, and 27648 multiplied by 77673 is 2147503104. That is the whole of the problem with fixed-point scaling in STL: the arithmetic is exact right up to the statement where it is not, and *D reports the crossing by setting OV and OS rather than by refusing to run. Here is … Read more
On an S7-1500 a 4 to 20 mA channel reads 0 counts at 4 mA and 27648 counts at 20 mA, and a channel with wire-break diagnostics enabled reads 32767 when the loop opens. Those three numbers decide the rest of this page: what goes in the MIN and MAX pins of NORM_X, what SCALE_X … Read more
Ladder, FBD, Structured Text, SFC and IL compared on real hardware: what Studio 5000 v33 and TIA Portal V18 support, and which one to pick per job.
A function block routine that verified fine last week now has a question mark on four blocks and will not download. Or worse, it downloads, runs, and one value on the HMI is always one scan behind the others. Nobody moved a block. Somebody added a wire. Execution order in FBD has nothing to do … Read more
Function Blog Diagram, whose short name is FBD, is not a highly preferred type of PLC programming language, but it allows us to do even the longest operations in a short way in most places and is easy to interpret. Although Function Block Diagram type is not one of the most commonly used PLC programming … Read more
How to Create Add-On Instructions in Logix Designer One of the most powerful newer features of the RSLogix 5000 program is the ability to create Add-On Instructions, It is one of the features that makes the algorithm easy and enjoyable for plc programmers. How to create and use the Add-On instruction Now we will go … Read more
Add-On Instructions Add-On Instructions are user-defined instructions. When you define an Add-On Instruction in a project it behaves similarly to a built-in instruction. You can define these instructions or they can be provided to you by someone else. An Add-On Instruction enables you to encapsulate your most commonly used logic as sets of instructions. These … Read more