![background image](http://html1.mh-extra.com/html/omron/ej1-07-2008/ej1-07-2008_operation-manual_743567151.webp)
132
Remote I/O Communications Characteristics
Section 7-1
Note
The measurement conditions are as follows:
Baud rate: 500 kbps
I/O allocation: Same as simple I/O allocation
Temperature Controller: TC2
The values above are reference values, not maximum values. The communi-
cations cycle time depends on the number of Temperature Controllers con-
nected and the type or number of the parameters allocated to I/O.
Refresh Time
The refresh time is the time required for I/O data to be exchanged between
the PLC's CPU Unit and the DeviceNet Master Unit. The PLC's cycle time is
increased when a Master Unit is mounted, as shown below.
Note
Refer to the PLC's Operation Manual for more details on the refresh time and
the PLC's cycle time.
Master Unit for CV-series
PLCs
The PLC's cycle time (CPU Bus Unit servicing) is increased by the amount
shown in the following table when a Master Unit is mounted to the PLC.
Master Unit for CS/CJ-
series, C200HX/HG/HE (-
Z), and C200HS PLCs
The PLC's cycle time (I/O refreshing) is increased by the amount shown in the
following table when a Master Unit is mounted to the PLC.
Note
The number of words refreshed is the total number of words in the I/O Area
that are allocated to the slaves, including any unused words between those
words actually used by the slaves.
For example, if there are only two Input Slaves with node addresses 1 and 5,
the 5 input words for nodes 1 through 5 would be refreshed even though the
input words for nodes 2, 3, and 4 are unused.
If message communications are being performed, just add the number of
words used in message communications to the above number of words for
whenever messages are being processed.
7-1-3
More than One Master in Network
The following equation shows the communications cycle time (T
RM
) when
there is more than one master in the Network.
An example for two Master Units is shown here.
Process
Processing time
CPU Bus Unit servicing
DeviceNet Unit refreshing: 1.1 ms
Process
Processing time
I/O refreshing
DeviceNet Unit I/O refreshing:
Using Master Unit for CS/CJ-series, and C200HX/HG/HE
(-Z) PLCs
1.72 + 0.022 × number of words (ms) (See note.)
Using Master Unit for C200HS PLCs
2.27 + 0.077 × number of words (ms) (See note.)
Summary of Contents for EJ1 - 07-2008
Page 3: ...iv...
Page 19: ...xx...
Page 33: ...14 Initial Temperature Controller Settings Section 1 4...
Page 53: ...34 Wiring the Temperature Controllers Section 3 4...
Page 101: ...82 Ladder Programming Examples Section 4 6...
Page 143: ...124 Sending Explicit Messages Section 6 5...
Page 155: ...136 Message Communications Characteristics Section 7 2...
Page 163: ...144 Maintenance Section 8 2...
Page 189: ...170 Allocation Numbers for Configurators Manufactured by Other Companies Appendix B...
Page 197: ...178 Index...