S7-300 multilevel Loop

[pboll]

Can S7-300 do multi-level loop?

I don't know where is wrong, I cannot do that. Is there somebody used that fuctions before?

Thanks in advance.

 

[RMA]

Sorry, but I think you need to explain your problem a bit more precisely. I, for one, am not clear what you mean by a "multi-level loop".

 

[pboll]

Sorry I don't know what's the official name of that kind of loops, it looks like:

===============
L 10
NEXT: T Loop01
...
...
L 20
NXT1: T Loop02
...
...
L Loop02
Loop NXT1

...
...
L Loop01
Loop NEXT
===============


I tested out successful in simulation, but when I download into 315, it faulted.

Any explaination?

Thanks.

 

[SimonGoldsworthy]

What fault was indicated in the diagnostic buffer ? This will almost always lead to to your coding error (cycle time, address does not exist, db does not exist etc.)

 

[pboll]

Stop caused by time error (OB not loaded, or not possible, or no FRB)

When I disable the inside loop or disable the outside loop, or set any loop number to 1, it's OK.

I guess I have to change one of the loops or change a PLC. I guess it only supported by highend such as 400, I can run it in simulation, not any problem.

 

[pboll]

Problem solved

I changed the outside loop code from

LOOP LP01

to


L loop01
L 1
-I
T loop01

A(
L loop01
L 0
>I
)
JNB LP01



Stupid 315!

 

[HenryLamboo]

I don’t know anything about Siemens but I think it is a timeout for controlling a kind of end less loop. The time it takes to execute you code is to long?

 

[PLucas]

Stop caused by time error (OB not loaded, or not possible, or no FRB)

The scan time is exceeding the maximum scan time set in the hardware setup due to the loops, the simulator probably ignores this.

If you are sure that the PLC can exit the loops, the loops are required and your process is not scan time dependant then you can up the maximum scan time allowed in the setup.

Paul

 

[SimonGoldsworthy]

The scan time is exceeding the maximum scan time set in the hardware setup due to the loops, the simulator probably ignores this.
Paul

The default scan time is set to 20secs when running in the simulator. If you click on the Execute option in the simulator you can change it to your own preference (or indeed disable it if you want to)

 

[pboll]

Is not a problem of scan time.

I changed 315 to maximum scantime setting which is 6000ms. I'm sure it's enough, but it's still faulted.

BTW, my regular scantime of the program is 80ms.

 

[PLucas]

Is not a problem of scan time.

Are you sure?

Stop caused by time error

That says it's a scan time fault.

I changed 315 to maximum scantime setting which is 6000ms. I'm sure it's enough

I wouldn't be so sure, Simon has stated that the default scan time for the simulator is 20 seconds, you have set the scan time on the 315 to 6 seconds, that still leaves a 14 second difference between the simulator and the 315.

Disable your loops then enable them one by one, checking the scan time each time until the PLC goes into stop, you will probably see that it is your loops taking the scan time over the maximum.

Paul

 

[SimonGoldsworthy]

The simulator runs an awful lot faster than a 315 so setting the same scan time in each will be like comparing chalk with cheese. Can you post the code segment with the nested loop (not in symbolic form) so we can have a look ?