Siemens SINUMERIK 840Di Function Manual page 1232

Detailed Description
2.7 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 operating modes
• Channel-specific signals such as program and feed modifications
• Axis- and spindle-specific signals such as feed disable
Auxiliary and G functions
The auxiliary and G functions have the following characteristics:
• Transfer to the PLC is block-synchronous (referred to a parts program block)
• Transfer is acknowledge-driven.
• The acknowledgment times have an immediate effect on the execution time of NC blocks
The value range is presented in the table below:
Function
G function
M word
S word
T word
D word
H word
F word
relative number, transferred for each G group
1)
corresponding STEP7 format (24-bit mantissa, 8-bit exponent)
2)
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
documentation "Lists of SINUMERIK 840D sl"). 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 high-speed 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.
2-38
containing auxiliary functions requiring acknowledgment.
Structure
1. Value
M group
Spindle no.
Magazine
no.
-
H group
Axis No.
Value range
2. Value 1. Value
G function
M word 99
S word 6
T word 99
D word 99
H word 99
F word 18
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Data type
2. Value 1. Value
255
1)
99,999,999 Word
Floating Word
point
2)
65535 Word
255 Byte
Floating Word
point
Floating Word
point
PLC Basic Program Solution Line (P3 sl)
2. Value
Byte
DWord
DWord
Word
Byte
DWord
DWord