Data Refreshing By Communications; Flow Of Communications Processing - Omron E5EK - MANUAL 2 User Manual

CHAPTER 6 USING COMPOBUS/D (DEVICENET)

6.2 Data Refreshing by Communications

+ Flow of
Communications
Processing
Peripheral services
PLC
Master unit
Communications writing
E5EK-DRT
T
WR
6–4
The E5EK DRT executes reading and writing of data by communications
as shown in the following figure:
Mirroring of communications written data
Reading of communications read data
Vendor-specific object services
*1 : This process is executed when there is a request for appended vendor-specific
services (page A-16) from the Configurator (option). Normally, this process is
not executed.
When the master is a programmable controller, the general flow of data is
as follows:
T
PLC
Instruction execution Peripheral services
T
RM
Communications reading
T
RD
TWR : E5EK DRT internal data write processing time
TRD : E5EK DRT internal data read processing time
TEXP : E5EK DRT internal vendor specific object processing time
TPLC : Cycle time on programmable controller
TRM : Communications cycle time
TRT : One slave communications time
For details on the communications cycle time and the one slave commu
nications times, refer to the CompoBus/D Operation Manual (W267). For
details of the cycle time on the programmable controller, refer to the
manual for the programmable controller that you are using.
Instruction execution
Vendor-specific Communications writing
T
EXP
*1
Peripheral services Instruction execution
T
RT
Communications reading Vendor-specific