Chapter 5. Power Supply / CPU
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5.6.5 Direct I/O operation function
This function is usefully available when an input junction state is directly read during execution of a program and used in
the operation, or the operation result is directly output to an output junction.
1) Direct input
• Direct input is executed by use of the ‘DIRECT_IN7’ function. If this function is used, the input image area will be
directly updated and applied to the continuing operations.
2) Direct output
• Direct output is executed by use of the ‘DIRECT_07’ function. If this function is used, the data of the output image
area, which has the operation results by the time, will be directly output to the direct output module.
3) Force on/off
• Force on/off settings are still effective when processing direct I/O.
5.6.6 External device error diagnosis function
Flags are given for the user to implement easily the program in which the error detection of external devices and system
stop and warning are coded. By use of these flags, error indication of external devices is possible without complex
programming and monitoring of the error location can be done without special tools (GMWIN, etc.) or source programs.
1) External device fault detection and classification
(1) The user program detects external device faults. The faults are classified into fatal fault (error), where the PLC stops
its operation, and ordinary fault (warning), where operation continues.
(2) The flag ‘_ANC_ERR [n]’ is used to indicate error. The flag ‘_ANC_WB [n’] is used to indicate warning.
2) External device fatal-fault (error) processing
(1) If an error of external device is detected and the error type, where other value than 0 is used, is written to the system
flag ANC_ERR [n], the flag will checked at the time that scan program finishes its execution. If an error is indicated on
the flag, it will be also indicated on the _ANNUN_ER of the representative system error flag _CNF_ER, the PLC turns
all output modules off and the error state will be same as the PLC self-diagnosis.
(2) The user can know the cause of error by use of the GMWIN, and also by direct monitoring of the flag _ANC_ERR [n].
(3) As the flag _ANC_ERR [n] has 8 elements (n: 0 to 7), the user can classify error states largely. User defined error No.
can be written to the elements. A number of 1 to 65,535 is available.
Example
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