OMRON PLC - How to Use OMRON PLC Function Block

Function Block potential of our Omron CS / CJ PLCs for future projects. Our typical projects include the control of a few hundred devices (doors, intercoms, cameras, card readers, etc.). It is generally of PLC logic, just the same, except that they shall refer to various IO addresses.

Desrcibe The logic that is suitable for your project, you are perfect for Function Block processing.

If you and add a Function Block instance, copy the same instance will be labeled as you describe.
You can create a new copy by right-clicking on the Function Block and the change of the name.

However, it is quite possible the same instance in multiple copies Function Block Function Block reuse. But be careful that you do so only if the Function Block-code can be worked in, a single scan, so there are no timers, counters and data control statements, such as PID, which require multiple scans complete.
So if you Function Block contains only simple functions the same conductor Function Block instance can use and saves space. If your case requires separate Function Block user, you can still edit and update all at once through the internals of Function Block Function Block invocations.
You can find Function Block to authorities under the symbol table data type “Function Block”.
For more information about Function Block, see the “CX-Programmer Operation Manual Function Blocks Structured Text” that are found in the CX-Programmer-folder in the Start menu.

I have a love-hate relationship with building blocks. In my experience:

Function blocks are good for:
1. Mathematics (transformations, scaling, floating-point calculations, etc.)
2. Loops (I find it much easier to code loops in structured text)
3. repetitive tasks such as door logic, logic cylinder, stop logic, etc.

Function blocks are bad because:
1. too much memory
2. adds scan time
3. difficult problems if you do not know how Function Block does
4. to test more work ahead and to document
5. can be dangerous if you try to get online editing and “accidentally” change all instances of the block

The newest and latest CX Programmer Version 4 CPUs possible Function Block can not be created / edited by online processing.
CPU version 4 function blocks can be processed online, but it can not be created (from scratch) online.
CX Programmer 7.0 or higher is required for this function.

The indirect nature of the programming can be very powerful when you get your head around ..
Just a little something about Function Blocks with Omron PLC:

Look in the PLC memory usage on the “View / See Memory (UM). Sorry, but I’m in the Cx-P Spanish!
Sometimes, when large Function BlockS (ie, floating-point calculations), or simply to build only Function Blocks Omron (as Mechatrolink or DeviceNet), the PLC CJ1M become small and it must be greater than PLC (CPU43 or higher).

Function Block is a good tool to typical problems of copy and paste causes the programming to avoid if you need more time in the same routine, order, or steps, but conscious memory (EMS) are!

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