KEYENCE SR-750 Series - Manual (Page 101)

101 E SR-750 UM
Data processing procedure using the handshake process
This section describes the data processing procedure using the handshake
process.
The following procedure is described using the example when the trigger input
measurement method of the SR-750 Series is set to the level signal trigger.
„ Timing chart
*1 Operations of OUT1 status and OUT2 status are described using the default
settings of the SR-750 Series operation and multi I/O.
*2 The read data ready count value and read data update count value may differ
depending on the operation status and communication frequency.
For example, when a code is read and then the next reading is complete before
updating the PLC data is complete, the result data ready count value will have
one more count value.
„ Data processing flow
1
When "Read Request" of PLC turns OFF (0) →ON (1), the SR-750
Series starts reading operation and turns "TRG BUSY" ON (1).
2
The SR-750 Series operates as follows when reading a code.
• It turns "TRG BUSY" OFF (0) and "Read Complete" ON (1), and then writes
the read operation result code to "Read Result Code".
• It turns "Read Data Update Available" ON (1).
* When reading is successful, the reading error cause is "0" (No error).
3
When "Read Complete" of the SR-750 Series is ON (1), turn "Read
Complete Clear" of PLC ON (1).
4
When "Read Complete Clear" of PLC turns ON (1), the SR-750 Series
turns "Read Complete" OFF (0).
When "Read Complete" OFF (0) is confirmed, turn "Read Complete
Clear" of PLC OFF (0).
5
If "Read Data Update Available" of the SR-750 Series is ON (1), turn
"Read Data Update Permitted" ON (1).
6
When "Read Data Update Permitted" of PLC turns ON (1), the SR-750
Series operates as follows.
• It turns "Read Data Update Complete" ON (1).
• It writes the read data and read data length to "Read Data" and "Read Data
Size".
(If append data has been set, the append data and delimiter are also
included.)
7
When "Read Data Update Complete" of the SR-750 Series turns ON
(1), process the obtained result data on PLC and turn "Read Data
Update Permitted" OFF (0).
m+1 m
m+1 m m+1
m+1
m
m
Attribute
Output
→
Iutput
←
Iutput
←
Output
→
Iutput
←
Iutput
←
Output
→
Iutput
←
Iutput
←
Iutput
←
Iutput
←
Iutput
←
Iutput
←
Iutput
←
Signal name
Read Request
TRG BUSY
Barcode/2D code
Read Complete
Read Complete
Read Complete Clear
Reading Error
Reading Error Cause
Read Data Update Available
Read Data Update Permitted
Read Data Update Complete
OUT1 Status (OK) *1
OUT2 Status (ERROR NG) *1
Read Data Ready Count *2
Read Data Update Count *2
Read Data and Data Size
When reading successful
0 201
Read data ERROR
When reading failed
8
When "Read Data Update Permitted" of PLC turns OFF (0), the SR-
750 Series turns "Read Data Update Available" and "Read Data
Update Complete" OFF (0).
11-3
Message Communication
This section describes how to use message communication.
Message communication (Explicit message)
Message communication overview
Message communication is a function that uses objects and services (Service
Code) prepared in the EtherNet/IP device and then issues and transmits
commands arbitrarily. Message communication is used for applications such as
reading and writing adaptor device settings.
There are established standard items, as well as device specific items in the
objects and services in message communication.
The SR-750 Series uses specific objects and services and can perform operations
such as parameter reading/writing and resetting.
Reference The SR-750 Series message communication function is compatible
with UCMM (unconnected type) and CLASS 3 (connected type).
Objects and services
In message communication, data are sent and received using objects and
services.
When services for SR-750 Series objects are executed, data output, settings
reading, and specified operations are executed.
Message communication basic format and process flow
During message communication, the EtherNet/IP scanner and the SR-750 Series
communicate by sending and receiving Explicit messages. The following shows a
basic example of sent Explicit message command formats and response formats
returned from the SR-750 Series.
Commands
The following are the command formats sent from the EtherNet/IP scanner to the
SR-750 Series.
„ Command formats
NOTICE
The SR-750 Series is equipped with the send buffer of 10 KB.
Even if the data processing on the PLC is unfinished, the next
reading operation is possible. (Operations 1 to 5 are possible.)
When the next result data is ready on the SR-750 Series, even if
"Read Data Update Permitted" of PLC changes ON (1)
→ OFF(0),
"Read Data Update Available" of the SR-750 Series maintains ON
(1) status without changing to OFF (0).
Repeat turning "Read Data Update Permitted" of PLC ON (1)/OFF (0)
until "Read Data Update Available" turns OFF (0). Or, send the
transmission buffer clear command (BCLR) from the command port
and delete data in the transmission buffer.
Item Description
Service code Specifies the Service.
Class ID Specifies the Class ID according to service.
Instance ID Specifies the Instance ID according to service.
Attribute ID Specifies the Attribute ID according to service.
Service data Specifies the Service Data according to service.