Data Exchange With Cpu Unit; Communications With The Cpu Unit - Omron SYSMAC C Series Operation Manual

Data Exchange with CPU Unit

5-4

Data Exchange with CPU Unit

5-4-1

Communications with the CPU Unit

CPU
Unit
76
The Unit communicates with the CPU Unit in 2-word mode using the I/O READ/
WRITE instructions in ladder logic. Specific ladder logic examples are in 5-7 Pro-
gramming Examples. Details about the ladder instructions and their execution
can be found in the Operation Manual for your PC.
The Unit has internal memory that provides storage for the Unit data and config-
uration parameters. This map contains both read and write areas, and is ac-
cessed by the CPU Unit through the I/O READ/WRITE ladder instructions.
The Unit is allocated two I/O words. The first word, referred to as "n" in this manu-
al, is used to output (write) data from the CPU Unit to the Analog I/O Unit. The
second word, n + 1, is used to input (read) data from the Analog I/O Unit to the
CPU Unit. The following diagram illustrates the basic data movements.
READ
Word n+1
WRIT
Word n
OUT Output bits
Bits 03 to 15 in word n
LD Input bits
Bits 03 to 15 in word n+1
Note The C500-AD501 requires the I/O READ and I/O WRITE instructions to operate.
It therefore cannot be mounted to a SYSMAC BUS Slave Rack.
RAM
addresses
Data read
000
to
045
Data written
046 (special
commands)
to
153
Data transferred
at startup
Data written to EEPROM
I/O
words
Section
Special commands
are used to transfer
data between
shared memory
and a Data Carrier.
EEPROM
EEPROM write setting
High/low alarm reset
Out-of-range error re-
set
Peak hold data reset
Setting errors
Conversion errors
High/low alarms
Out-of-range alarms
5-4