Omron CVM1 Series, Operation Manual

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PLC Operation Mode (Synchronous/Asynchronous Mode) Section 3-5
3-4-4 CPU Bus Unit Status Flags
Since the PC Link Unit is a CVM1/CV-series CPU Bus Unit, the following Aux-
iliary Area flags and control bits are used to indicate status or control opera-
tion of the Unit.
The C1000H/C2000H PLCs do not have an equivalent area, but these flags
can be used after replacing a C1000H/C2000H Rack with a CVM1/CV-series
Rack.
3-5 PLC Operation Mode (Synchronous/Asynchronous Mode)
The CVM1/CV-series CPU Units can be set to synchronous mode or asyn-
chronous mode. In synchronous mode, the CPU Unit synchronizes process-
ing of the instruction execution cycle (instruction execution and I/O refreshing)
and peripheral servicing cycle (peripheral servicing of devices such as CPU
Bus Units). Asynchronous mode is an non-synchronized, high-speed pro-
cessing mode.
The default processing setting is asynchronous mode. For details, refer to the
CV Ladder Diagram Operation Manual (W202-E1-5).
• The PC Link Unit is a CPU Bus Unit, so the LR Area is refreshed in the
peripheral processing cycle.
Word Bit(s) Name Function
A001 00 to 15 CPU Bus Unit Restart Bits These bits can be turned ON to reset the corresponding CPU Bus Units.
The Restart Bits are turned OFF automatically when restarting is com-
pleted. (Bits 00 to 15 correspond to unit numbers 0 to 15.)
A015 00 to 15 CPU Bus Service Disable
Bits
These bits can be turned ON to stop service to the corresponding CPU
Bus Units. (Bits 00 to 15 correspond to unit numbers 0 to 15.)
Turn the bit OFF again to resume service to the CPU Bus Unit.
A302 00 to 15
CPU Bus Unit Initializing
Flags
ON while the corresponding CPU Bus Units are initializing. (Bits 00 to 15
correspond to unit numbers 0 to 15.)
A401 12
CPU Bus Error Flag
ON when an error occurs during the transmission of data over the CPU
bus, or a WDT (watchdog timer) error occurs in a CPU Bus Unit. The unit
numbers of the affected CPU Bus Units are indicated in word A405.
A401 13
Duplication Error Flag
ON when two Racks are assigned the same rack number, two CPU Bus
Units are assigned the same unit number, or the same words are allocated
to more than one Rack or Unit in the PC Setup. The unit numbers of the
affected CPU Bus Units are indicated in word A410.
A402 03
CPU Bus Unit Setting Error
Flag
ON when the CPU Bus Units actually installed differ from the Units regis-
tered in the I/O table. The unit numbers of the affected CPU Bus Units are
indicated in word A427.
A402 07
CPU Bus Unit Error Flag
ON when an error occurs during the transmission of data between the PLC
and CPU Bus Unit. The unit numbers of the affected CPU Bus Units are
indicated in word A422.
A405 00 to 15
CPU Bus Error Unit Num-
ber
ON when an error occurs during the transmission of data over the CPU
bus, or a WDT (watchdog timer) error occurs in a CPU Bus Unit. (Bits 00 to
15 correspond to unit numbers 0 to 15.)
A410 00 to 15
CPU Bus Unit Duplicate
Number
ON when two CPU Bus Units are assigned the same unit number. (Bits 00
to 15 correspond to unit numbers 0 to 15.)
A422 00 to 15
CPU Bus Unit Error Unit
Number
ON when an error occurs during the transmission of data between the PLC
and CPU Bus Unit. (Bits 00 to 15 correspond to unit numbers 0 to 15.)
A427 00 to 15
CPU Bus Unit Setting Error
Unit Number
ON when the CPU Bus Units actually installed differ from the Units regis-
tered in the I/O table. (Bits 00 to 15 correspond to unit numbers 0 to 15.)