Omron SYSMAC CV Series - CPU Bus Link Area

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3-5 CPU Bus Link Area
The CPU Bus Link Area is indicated by a G prefix. Addresses range from G000
to G255. The CPU Bus Link Area can be divided into 3 sections, the PC Status
Area, Clock/Calendar Area, and Data Link Area.
G000 is the PC Status Area and contains flags and control bits relating to PC
status. G001 to G004 are the Clock/Calendar Area, and G005 to G007 are not
used.
Most of the CPU Bus Link Area (G008 to G255) is taken up by the Data Link Area
which is used to transfer information between CPU Bus Units and the CPU. CPU
Bus Units connect to the CPU bus on the CPU Rack or Expansion CPU Rack.
Caution The CPU Bus Link Area words G000 through G007 cannot be written to from the
user program and can only be read from to access the data provided there.
PC Status Area The following table shows the specific functions of flags and control bits in
the PC Status Area, G000.
G000 bit(s) Function
00 ON when the PC is in PROGRAM mode.
01 ON when the PC is in DEBUG mode.
02 ON when the PC is in MONITOR mode.
03 ON when the PC is in RUN mode.
04 ON when the program is being executed (RUN or MONITOR mode).
05 Not used.
06 ON when a non-fatal error has occured. (PC operation continues.)
07 ON when a fatal error has occured. (PC stops.)
08 to 10 Not used.
11 UM Protect Bit. Prevents both reading out and writing to Program
Memory when turned ON. Set with the CVSS/SSS.
12 Memory Card Protect Bit. Prevents writing to Memory Cards when
turned ON. Set with the Memory Card Protect Switch.
13 and 14 Not used.
15 UM Protect Bit. Prevents writing to Program Memory when turned
ON. Set with the System Protect Key Switch.
Calendar/Clock Area The following table shows the function of bits in the Calendar/Clock Area,
G001 to G004. The clock is set with the CVSS/SSS. Refer to the CVSS/SSS
Operation Manuals for more details.
Word Bits Contents Possible values
G001 00 to 07 Seconds 00 to 59
08 to 15 Minutes 00 to 59
G002 00 to 07 Hours 00 to 23 (24-hour system)
08 to 15 Day of month 01 to 31 (adjusted by month and for leap year)
G003 00 to 07 Month 1 to 12
08 to 15 Year 00 to 99 (Rightmost two digits of year)
G004 00 to 07 Day of week 00 to 06 (00: Sun.; 01: Mon.; 02: Tues.;
03: Wed.; 04: Thurs.; 05: Fri.; 06: Sat.)
Note The accuracy of the internal clock depends on the ambient temperature. Refer
to the following table.
Ambient temperature Error per month
55C
–3 to 0 min
25C
±1 min
C
–2 to 0 min
CPU Bus Link Area Section 3-5