Siemens SINUMERIK 840Di Function Manual page 958

Detailed description
2.7 Structure and functions of the basic program
The following functions are performed in the cyclic part of the basic program:
• Transmission of the control/status signals
• Distribution of the auxiliary and G functions
• M decoding (M00 - M99),
• M, S, F distribution
• Transmission of the machine control panel signals via the NCK (on the 840D only)
• Acquisition and conditioning of the user errors and operating messages.
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-groupspecific signals such as operating modes
• 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 acknowledgecontrolled.
• 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 STEP 7 format (24-bit mantissa, 8-bit exponent)
2)
2-46
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
Power Line Basic PLC Program (P3)
2. Value
Byte
DWord
DWord
Word
Byte
DWord
DWord