Precautions - Mitsubishi Electric M800VW Series Manual

M800V/M80V Series PLC Development Manual
5 Peripheral Development Environment (GX Works2)
5.6 Developing Simple Project

5.6.8.9 Precautions

Restrictions on program configuration
(1) Limitations on independent program method
Ladder program writing during RUN is not available for the sequence program in independent program method. Bit selec-
tion parameter setting is not available. Still, program execution is available.
(2) Limitations on high-speed processing program
If you set the bit selection parameter to enable "ladder program writing during RUN (in high-speed processing)", a write to
a high-speed processing program is enabled during RUN. However, the following limitations are imposed:
(a) Available execution steps
The following is the maximum number of available execution steps for a high-speed processing program.
If the number has been exceeded during RUN write, an error will occur.
 The maximum number of available execution steps is 4,000.
(When the multi-project function is enabled, the total number of steps for all projects will be 4,000).
 8,000 steps of execution area will be used regardless of the size of high-speed processing program.
(b) Available number of local labels
The following is the number of available local labels in a high-speed processing program.
If the number has been exceeded during RUN write, an error will occur.
 The maximum number of local labels is 256.
(When the multi-project function is enabled, the maximum number of local labels will be 256 per project.)
 If the number of local labels is set to 256 or less, the set number will be the maximum number of local labels.
(c) Use of common pointers in high-speed processing program
RUN write is disabled when the common pointer is used in a high-speed processing program. In this case, the bit selection
parameter for enabling RUN write will be disabled. Still, program execution is available.
If you perform RUN write for a high-speed processing program, use a local pointer only. The following is an example of the
use of common pointer for subroutine call from standby processing program.
× RUN write invalid
○ RUN write valid
(3) Limitations when the multi-project function is enabled
RUN write cannot be performed to different projects through multiple development tools at the same time.
If attempted simultaneously, an error will occur. Try RUN write again after shifting the timing.
(4) Limitations on independent program method
When the multi-project function is enabled and a sequence program in independent program method is included in any
project, the ladder program writing during RUN cannot be executed for high-speed processing program in all projects.
Hi-speed process program
CALL
P1804
P1804
END
Main process program P1805
CALL P1805
END
151
Standby process program
CALL P0
RET
RET
END
IB-1501614-B