JSR in RSLogix5000

[daba]

^that is the way i always do it. Its significantly faster/easier than searching through all the tabs and trying to find the JSR one anyway.

Do you really use the tabs to find instructions?

Have you tried pressing the Insert key on your keyboard?

Try it, then start typing the instruction mnemonic, as soon as the box shows the instruction you want, just hit enter. Nothing else, just hit insert, then key in J, the display will go straight to JMP - then hit S, the display goes to JSR, hit enter, and job done. In most cases, you only need to press the first letter of the instruction mnemonic, some cases 2, and rarely 3.

I never use the multiple tabs of the Instruction Element Toolbar - it's tedious.....

 

[Geospark]

...So now we have a little problem. If we put SBR where it must be, what do we put on the rest of the rung? If we start to put application logic, we have mixed Program Control Instructions and application instructions on the same rung, and that's not a good idea...

...I would recommend that when you are using SBR's, that you put them on a rung to themselves, with a NOP as the output on that rung. Doing so will isolate the program control instruction from the application code.

daba,

I would agree with the use of a NOP after SBR for clarity, but can you explain why it's not a good idea to mix program control instructions and application instructions on the same rung? I don't mean in general, but specifically after an SBR?

It's my understanding that the SBR is always evaluated true. So, while it is "there" as far as the scan is concerned, it's as though it isn't "there" as far as application logic is concerned. So you should be able to start your application logic on the first rung after an SBR instruction?

An XIC and OTE, for instance, directly after an SBR on the first rung would act as though the XIC is the first instruction. The OTE instruction would only be dependant on the XIC and not the SBR.

Also, if using a conditional rung ending in a JSR instruction, there would be a mix of application and program control instructions here.

What potential problems are there in mixing?

G.