Reading In G Functions; Interface Signal; Display; Fifo/Predecoding - Siemens SINUMERIK 840C Installation Instructions Manual

09.95

12.9.6 Reading in G functions

G functions G36 and G98 can be read by the user with FB69 via the PLC and with @36b from
the NC program.

12.9.7 Interface signal

2)
DB 10 - DB 13 , bit 4
Byte
address 7
DR 13

12.9.8 Display

G36 and G98 are displayed in the display field G functions.
The feedrate F is displayed with G36 and/or G98 are programmed in rev/min (refers to the
rotary axis).
12.10

FIFO/predecoding

12.10.1

Rapid block change using FIFO function (up to SW 2 only)

Corresponding data
• NC MD 5186 bit 4
• NC MD 9140 bit 0
9141 bit 0
9142 bit 0
9143 bit 0
Description of function
When part programs with short traversing blocks are processed, sudden drops in feedrate can
occur because the time taken by the block preparation function to process the short
tranversing blocks is longer than the time taken to execute these blocks. The block change
time (block preparation + block transfer) is too long in such a case.
A shorter block change time results if processing is carried out with the FIFO function.
A block buffer (FIFO memory) is first filled after NC START or by programming G171.
_______
1) The FIFO function is omitted from SW 3 onwards
2) As from SW 4: DB 10 - DB 15
© Siemens AG 1992 All Rights Reserved
SINUMERIK 840C (IA)
"Thread cutting position controlled spindle"
(Rigid tapping)
Bit No.
6 5 4
G36
must be set.
FIFO active in channel
6FC5197- AA50
12 Functional Descriptions
12.9.6 Reading in G functions
3 2 1 0
1)
12–71