July 2013 9.5 Data Transfer NC > PLC, PLC > NC 1713
9.5 Data Transfer NC > PLC, PLC > NC
Information is exchanged between PLC and NC by markers, bytes, words and
double words. The function of the individual markers, bytes, words and double
words is fixed.
The transfer of certain data to the PLC is controlled by strobes:
M codes
S codes
T codes
G codes
Q codes
Example:
If an M function is output, the NC sets the strobe signal M4072. After
evaluating the M function, you must first set the acknowledgement marker
M4092 and then reset it. The PLC must then reset the acknowledgment
marker, otherwise no further strobes can be sent by the NC.
9.5.1 Data transfer NC program > PLC (FN19: PLC =)
With the Q-parameter function FN19: PLC = you can transfer two values from
an NC program to the PLC. The iTNC stores the transferred values as integer
values of the form 1/10 000 in the double words D280 and D284. M4570
defines the unit of measure of both numerical values. During transfer, the
marker M4075 is set by the NC. The PLC must acknowledge the transfer by
setting marker M4095.
PLC messages that would terminate an NC strobe are only released once
all PLC functions that are only permitted during the strobe have been
completed.
If there is an emergency stop, current NC strobes are automatically
acknowledged by the NC, and in this case should not be acknowledged
additionally by the PLC.
Set Reset
M4075 Transfer active with FN19 NC NC
M4095 Acknowledgment of transfer with
FN19
PLC PLC
M4570 Unit of measure for transfer with
FN19
0: mm
1: inches
NC NC
D280 First numerical value from FN19 NC NC
D284 Second numerical value from FN19 NC NC
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