S5-100U cpu 103 OB21

[tulip]

Hi.I want to migrate S5-100U CPU 103 program to S7.It is giving error due to the following lines.These lines are exist in OB21.


L KH 4435
T RS 8
L KH 1E44
T RS 9
L KH 351D
T RS 10

What is this? Thanks in advance...

 

[JesperMP]

"L KH" loads a hexadecimal value
"T RS" transfer the accumulator to a system data area.

The manual for Siemens S5-100U system says inexplicably

Since system operations access system data, only users with system knowledge should use them.
If you want to program system operations, you must select “SYS: OPS. Y” in the programmer presets menu.

So it is something that set a system function but I do not have insight in the details about the system data area.

It is all a bit mysterious.
If you look at the index of this manual
https://cache.industry.siemens.com/dl/files/978/1091978/att_19648/v1/6ES5_998-0UB23.pdf
it says that there is a chapter for "system parameters" called "5-14". But the last page in chapter 5 is 5-13. As if it has been stripped out but someone forgot to update the index.

Maybe someone knows ?

 

[JesperMP]

Chapter 6-16 says that system areas 8-12 are related to the integral real-time clock.

 

[parky]

If my memory serves me right the system data area is as follows so I presume in the startup OB it is some area of the real time clock no idea what this is supposed to do KH is hex mode
5 to 7 ISTACK (Interrupt STACK)
8 to 12 Integral real-time clock
33 First free program memory address
35 Program memory starting address
37 Program memory end address
40 to 45 CPU version, software release
57 to 63 SINEC L1
96 Scan monitoring time (value . 10 ms)
97 Calling interval for OB 13 for time-controlled program
processing (value .
10 ms)
128 to 159 BSTACK (Block STACK)
203 to 214 ISTACK (Interrupt STACK)
Setting values in the system data area is usually done in the startup OB's I think without setting the clock it does not run but I cannot remember how it works the data they are pushing into it seems a little weird but perhaps this is just to start the system clock, perhaps they only use some values for example a 1 minute pulse based on the minute register changes every minute somewhere else in the program.
A word of warning converting S5 to S7 often either built in blocks or Siemens purchased blocks will not convert, the conversion does produce these but are often empty so you have to create your own to make it work, an example of this is Siemens sold blocks for sequencers like a drum type, when converted to S7 the FB is there but contains no code so in reality there is often no direct conversion especially if this was coded in Europe.