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Memory Card Backup Functions Section 7-2
a maximum of four-fold (for a communications speed of 500 Kbps) in com-
parison with connection by a peripheral bus.
2. Temporarily extend the communications cycle time.
Operate the CX-Programmer after extending the cycle time in the Commu-
nications Cycle Time Setup Table (word m) in the DM Area, and turning ON
the Temporary Setting Switch for Communications Cycle Time (word n, bit
12).
Extending the communications cycle time 1.5 times will result in a 20%-
30% improvement in response. However, whereas the CX-Programmer re-
sponse will increasingly improve by extending the communications cycle
time, the remote I/O communications response will suffer.
Note The CX-Programmer response decreases in accordance with decreases in
the DeviceNet communications speed. At a speed of 125 Kbps, response will
suffer by up to a twenty-fold drop in comparison with connection by a periph-
eral bus.
Accordingly, a DeviceNet communications speed of 500 Kbps is recom-
mended when the CX-Programmer is connected to the network via the
DeviceNet Unit.
7-2 Memory Card Backup Functions
The DeviceNet Unit stores the following setup data in the internal non-volatile
memory (EEPROM).
• Master scan lists
• Slave scan lists
• Message monitoring timer lists
• Communications cycle time settings
• Master/Slave functions enabled/disabled settings
Note Backup is possible only when scan lists are enabled.
With the CS/CJ-series DeviceNet Unit, all this setup data can be backed up to
and restored from a Memory Card mounted to the CPU Unit. (See note.)
Note The data can be backed up to a Memory Card only. It cannot be backed up to
a EM file.
If all setup data for a DeviceNet Unit that starts normally is saved on a Mem-
ory Card, that data can be read and used when replacing DeviceNet Units,
making the replacement process smooth.
Device parameter files (.dvf files) created using the Configurator can be saved
from the computer to the Memory Card and can be restored to the DeviceNet
Unit mounted to the CPU Unit. This means that setup data created using the
Configurator (scan lists and other parameters) can be downloaded to
DeviceNet Units simply by taking the Memory Card to site.