Siemens SINUMERIK 828D Function Manual page 878

P3: Basic PLC Program for SINUMERIK 840D sl
13.8 Structure and functions of the basic program
Control/Status signals
A shared feature of the control and status signals is that they are bit fields. The basic program updates them at
the start of OB1.
The signals can be subdivided into the following groups:
• General signals
• Mode group-specific signals (such as mode types)
• Channel­specific signals (such as program and feed modifications)
• Axis- and spindle­specific signals (such as feed disable)
Auxiliary and G functions
The auxiliary and G functions have the following characteristics:
• Transfer to the PLC is block­synchronous (referred to a parts program block)
• Transfer is acknowledge­driven.
• The acknowledgment times have an immediate effect on the execution time of NC blocks containing auxiliary
functions requiring acknowledgment.
The value range is presented in the table below:
Function Structure
1. Value
G function
M word M group
S word Spindle no.
T word Magazine
no.
D word -
H word H group
F word Axis No.
1)
relative number, transferred for each G group
The M, S, T, H, D and F values sent by the NCK are output together with the accompanying change signals to
the CHANNEL DB interface via the auxiliary/G functions (see List Manual). The function value and the extended
address are transferred to the appropriate data word. The accompanying modification signal is activated to 1 for
one PLC cycle. When the modification signal is reset, the acknowledgment is passed to the NCK. The
acknowledgment of high­speed auxiliary functions is given by the basic program immediately the basic program
detects the auxiliary function.
In addition to distribution of the auxiliary and G functions, selected signals are processed as described below.
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Range of values
2. Value 1. Value
G function
M word 99
S word 6
T word 99
D word 99
H word 99
F word 18
Data type
2. Value 1. Value
1)
255
99.999.999 Word
Floating Word
2)
point
65535 Word
255 Byte
Floating Word
point
Floating Word
point
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
2. Value
Byte
DWord
DWord
Word
Byte
DWord
DWord
Basic Functions