Omron SYSMAC CS1W-SCB41-V1 Operation Manual page 43

Features
Host Link
Protocol Macros
Wide Range of
Communications
Protocols
Send Frames and Receive
Frames Matching
Specifications
Communications-related
Functions
Send/Receive Monitoring
Retry Processing
PLC Read/Write Variables
in Send Frames and
Receive Frames
Switch 1:N
Communications or the
Data Write Destinations
Using Repeat Processing
PLC Interrupts During
Data Reception
Next Process Switching
According to Receive Data
New Error Check Codes
Step Queuing for Sync
Signal from the PLC
Half-duplex or Full-duplex
Transmissions
14
Bridge
Controller Link Network
The main features of the protocol macro functions are described below. For
details, refer to the CX-Protocol Operation Manual (W344).
Communications are possible with virtually any general-purpose external
device, provided it has an RS-232C or RS-422A/485 port, supports half-
duplex or full-duplex communications, and supports start-stop synchroniza-
tion.
Send frames (command + data and other send frames) and receive frames
(response and other frames) can be created and registered according to the
communications frame specifications of the external device.
Error check code calculations, frame length calculations during sending, and
ASCII ⇔ Hexadecimal conversion of numeric data are supported.
Receive wait monitoring, receive completion monitoring, and send completion
monitoring are supported. If monitoring times are exceeded, send/receive can
either be terminated, or retry processing can be performed.
Send/receive retry processing can be automatically executed when an error
occurs, simply by setting the number of retries.
Variables for reading PLC memory can be included in the actual send frames.
These can be used as destination addresses or data when reading PLC data
while sending. Variables for writing to PLC memory can be also included in
the actual receive frames. These can be used to write the contents of destina-
tion addresses or data to the PLC during reception.
Repeat processing (repeat counters) for send/receive processing can be
specified in communications sequences. This enables the same data to be
sent by switching destination addresses during communications 1:N (N = 32
max. due to restrictions in the physical layer) or by switching the PLC memory
write destination addresses during data reception.
An interrupt can be created in the PLC's CPU Unit during data reception, and
an interrupt program can be executed in the CPU Unit. (The PLC interrupt
function is supported only for the Serial Communications Boards. This func-
tion cannot be used with Serial Communications Units.)
The contents of up to 15 set of expected receive data can be compared with
the receive data to determine the next process.
LRC2 (two's complement of LRC), and SUM1 (one's complement of SUM)
have been added to the error check codes.
At any step of the communications sequence, the next process can be made
to wait until a sync signal from the PLC's CPU Unit has been input. This
enables processing, such as data manipulations, to be performed in the CPU
Unit during the communications sequence.
With the conventional protocol macro functions, only half-duplex transmis-
sions were possible. With half-duplex mode, the reception buffer is cleared
Ethernet Network
Controller Link Network
Gateway
Section 1-4
SEND(090),
RECV(098),
CMND(490)