Function Mode of the CREAD_REG
Block
Although a large number of CREAD_REG
function blocks can be programmed; only four read operations may
be active at the same time. In this case it is irrelevant whether
they are the result of this function block or others (e.g. MBP_MSTR
, MSTR
, READ_REG
). All function blocks use one data transaction path and require
multiple cycles to complete a job.
NOTE: A TCP/IP communication
between a Quantum PLC (NOE 211 00) and a Momentum PLC (all TCP/IP
CPUs and all TCP/IP I/O modules) is only possible, when only one read or write job is carried out in every cycle. If several jobs
are sent per PLC cycle, the communication stops without generating
an error message in the status register of the function block.
All routing information is contained in the WordArr5
data structure of the ADDRFLD
input. The type function
block assigned to this input is defined by the network used.
Please use:
Modbus Plus for function block
ModbusP_ADDR
TCP/IP Ethernet for function block
TCP_IP_ADDR
SY/MAX Ethernet for function block
SYMAX_IP_ADDR
NOTE: The
WordArr5
data structure
can also be used with constants.NOTE: This function
block puts a heavy load on the network; therefore the network load
must be carefully monitored. If the network load is too high, the
program logic should be reorganized in order to work with the
READ_REG
function
block, a variation of this function block that does not operate in
a continuous mode, but under command control.