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APPENDIX 3 List of Special Registers
The special registers are used for specific purposes in the A2C.
Table 3.1 shows the special registers and their purposes.
It is impossible to write data to those special registers not marked with *1 or
*2. (Read only)
(a) *1 Special registers: Reset (0) only.
(b) *2 Special relays: Data can be written.
Check their purposes when used in the sequence program.
Table 3.1 List of Special Registers
• When fuse blow modules are detected. the lowest
number of detected units is stored in hexadecimal.
(Example: When fuses of Y50 to 6F output modules
have blown, "50· is stored in hexadecimal) The
module number monitored by the peripheral is
(Cleared when all contents of 09100 to 09107
are reset to
• If I/O module data is different from data entered
are detected when the power is turned on, the first
I/O number of the lowest number module among
the detected modules stored in hexadecimal.
(Storing method is the same as that of 09000.)
The module number monitored by the peripheral is
• (Cleared when all contents of 09116 of 09123 are
• 1 is added each time input voltage becomes 80%
or less of rating while the CPU unit is performing
operation, and the value is stored in BIN code.
• When error is found as a result of self-diagnosis,
error number is stored in BIN code.
• When one of Fe to 255 is turned on by [OUT F] or
[SET F], the F number, which has been detected
earliest among the F numbers which have turned
on, is stored in BIN code.
cen be cleered by [RSTF] or [REOR]
instruction. If another F number has been
detected, the clearing of 09009 causes the next
number to be stored in 09009.
• When operation error has occurred during
execution of application instruction, the step
number, at which the error has occurred, is stored
in BIN code. Thereafter, each time operation error
occurs, the contents of 09010 are renewed.