·367·
CNC 8035
(SOFT M: V15.3X)
(S
OFT T: V16.3X)
11
ACCESS TO INTERNAL CNC
VARIABLES
The CNC has a number of internal variables that may be accessed from the user program, from
the PLC program or via DNC. Depending on how they are used, these variables may be read-only
or read-write.
Reading and writing variables from the PLC
The PLC provides two instructions (actions) which permit to read or modify the various internal
variables of the CNC from the PLC.
Reading variables. –CNCRD– command
The CNCRD command allows reading the CNC's internal variables. Its programming format is:
CNCRD (Variable, Register, Mark)
This PLC action loads the contents of the indicated variable into the selected register. If this
instruction has been executed properly, the PLC will assign a value of "0" to the indicated "error
detection" mark and "1" if otherwise.
When requesting information about a nonexisting variable (i.e. the position value of a nonexisting
axis), this instruction will not alter the contents of the register and it will set the selected error mark
indicating that the variable does not exist.
Writing variables. –CNCWR– command
The CNCWR command allows writing the CNC's internal variables. Its programming format is:
CNCWR (Register, Variable, Mark)
This PLC action loads the contents of the indicated register into the selected variable. If this
instruction has been executed properly, the PLC will assign a value of "0" to the indicated "error
detection" mark and "1" if otherwise.
When trying to modify the contents of a nonexisting variable or assign an improper value to it, the
selected "error mark" will be set to "1" which will indicate that this instruction is incorrect.
When performing an improper reading or writing request, the PLC will continue the execution of the
program unless interrupted by the programmer after having analyzed the "error" mark defined in
the instruction.
CNCRD (FEED, R150, M200)
It loads the value of the feedrate selected at the CNC when working in G94 into the PLC
register R150.
CNCWR (R92, TIMER, M200)
It resets the clock enabled by the PLC with the value contained in register R92.
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