Data Refreshing By Communications - Omron E5EK DEVICENET User Manual

J E5EK-DRT
Internal
Processing Times
F Data write
processing time
F Data writing processing time
F Vendor-specific object processing time
F Example of actual
calculation
The E5EK-DRT internal processing times are as follows:
• Writing of data other than operation instructions in the RAM write
mode
0.5 ms per data item
• Writing of data other than operation instructions in the EEPROM
backup mode
17 ms per data item
• Operation instructions: save RAM data
120 ms
• Operation instructions: instructions other than save RAM data
0.5 ms
• 0.5 ms per data item
• Get attribute single : 50 ms
Set attribute single
• Let's assume that the E5EK-DRT is in the factory shipped state, that
one E5EK-DRT is connected with a master unit (C200HW-DRM21) in
a point-to-point configuration, and that the programmable controller
scan time is 2 ms.
Baud rate 125 kbits/second
4 channels (set point, alarm value 1, alarm value 2, operation
Write data assignments
instruction)
Read data assignments 3 channel (PV monitor, manipulated variable (heat), status A)
Backup mode RAM write mode
When "change alarm value 1" and "stop mode to run mode operation
instruction" operations are executed simultaneously, the processing
time it takes until the communications data is mirrored on the E5EK-
DRT can be calculated as follows:
T=T +T +T +T
PLC RM WR
T=2+2.426+1+1.5+0=6.926ms
where,
T =2ms
PLC
T =2.426ms
RM
T =0.5ms+0.5ms
WR
T =0.5ms+0.5ms+0.5ms (3 channels read at all times)
RD
T =0ms
EX
Note: In the above example, the actual processing time is sometimes
extended by a maximum of about 80 ms when operation also
involves key-switching between the remote and local modes.
When keys are not operated (that is, only control processing and
communications processing are executed), the actual processing
time is sometimes extended by a maximum of about 10 ms. Please
take this into consideration when calculating processing times
under the worst conditions.

6.2 Data Refreshing by Communications

: 0.5 ms
+T
RD EXP
(at above conditions)
(at alarm value 1 and operation
instruction change)
(During normal operation, vendor-
specific object services are not processed.)
6--5