Machine Data And Their Structure - Siemens SIMATIC S5 Manual

2.5

Machine Data and their Structure

Before a positioning module such as the IP247 can execute a positioning operation automat-
ically, it must be provided with information
as machine data. Machine data is stored in a data block along with other parameters. This has a
constant length. Machine data can be divided into the following parameter groups:
specific to the power unit
specific to the stepper motor
specific to the plant
specific to the operations
specific to the machining program
Using the COM247 software package, machine data records can be generated efficiently and
easily at the programmer and transferred to the positioning module. Once on the module they
can be read again, corrected or deleted. Both COM247 and the module perform consistency
checks. If machine data are sent to the IP247 via the PC interface, they are only checked by the
I P247. It is therefore possible to assign bad machine data to an axis on the module.
Bad in this case means that either data in the machine data record exceed the stipulated limit
values, or that certain combinations of machine data are not permitted.
If a bad machine data record is transferred to the positioning module, the IP247 signals the error
"error in machine data" via the PG and PC interface. The type of error itself, e.g. "wrong axis/mod-
ule number" is stored by the firmware of the positioning module in the machine data block (=>
Part 7, "Planning, Installation and Service"). If you enter the machine data using the COM247 soft-
ware package, the type of machine data error is displayed in plain text in the error message line
on the PG. The message "error in machine data" is then overwritten.
If you wish to position using all the axes of the IP247, a machine data block (DB) must be stored
on the module for each axis. You can assign a machine data block with the same DB number to
different axes.
If no correct machine data are stored on the IP247 for an axis, the axis is not operational. If oper-
ating instructions are sent to the axis, the job is rejected with the error message "wrong or no ma-
chine data".
If you edit the machine data record using the COM247 software package, all the required ma-
chine data are requested in plain text using a menu technique. Following the input field, the de-
fault dimensional unit and the permitted range of values is displayed. This is explained in detail in
Part 5"COM247 Communications Software".
Since no special software is available for planning the machine data in the CPU, the following de-
scription of the individual machine data includes the data formats as required for entry or storage
in the CPU. A table in Part 6 "Standard Function Blocks FBI 64 and FBI 65" provides an overview
of these formats.
Machine Data and their Structure
about the connected drive.
This information is known
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