Considerations For Use - Mitsubishi Electric MELSEC iQ-R Series User Manual

CONSIDERATIONS FOR USE

This section explains the following considerations.
Page 9 Considerations for performance and specifications
Page 9 Precautions for the streaming transfer, data read, and data write functions
Page 10 Considerations for other functions
Page 10 Considerations for accessing a high speed data communication module
Page 10 Considerations for security
Page 10 Considerations for using an SD memory card
Considerations for performance and specifications
■Sequence scan time of a CPU module
• Using a high speed data communication module may increase the scan time of a CPU module. Design a system and
programs keeping in mind this increase in sequence scan time of the CPU module. (MELSEC iQ-R High Speed Data
Communication Module User's Manual (Application))
■Network connection using Ethernet
• When connecting to an Ethernet network, basically configure the communication route to an access target with Ethernet
(twisted pair) cables and hubs. If using a device such as a wireless LAN (Wi-Fi) or router, note that communication may not
be established properly due to an error such as timeout or data missing depending on the status of the device or configured
route.
• If the access load to a high speed data communication module is high, the following issues may occur due to an error such
as timeout or data missing: a streaming transfer, data reading and writing take time, and communication with the module is
not established properly. In this case, reduce the load on the Ethernet network to which the module is connected.
■Time handled on a high speed data communication module
• Time handled on a high speed data communication module is the time on a CPU module. For details on errors and the
optimum timing for setting the time, refer to the following:
(Page 19 Performance Specifications)
(MELSEC iQ-R High Speed Data Communication Module User's Manual (Application))
■High speed sampling
• High speed sampling is not supported by CPU modules on other stations via a network.
Precautions for the streaming transfer, data read, and data write functions
• The streaming transfer, data read, and data write functions are of the best effort type. Since the processing time of a
module and data transfer time varies depending on the settings and the status of a network and other devices, these
functions may not perform at the set sampling interval and transfer cycle. Run the system by fully verifying the processing
time of each function and the data transfer time when constructing it. For details on processing time, refer to the following:
(MELSEC iQ-R High Speed Data Communication Module User's Manual (Application))
• If the streaming transfer, data read, and data write functions are used, they affect on the sequence scan time of the access
target CPU. Run the system by fully verifying the affect to the sequence scan time when constructing it. For details on the
influence on the sequence scan time, refer to the following:
(MELSEC iQ-R High Speed Data Communication Module User's Manual (Application))
• When a linear function is converted using the scaling function, a rounding error may occur depending on the type of data
being output.
• Since general sampling specified data is sampled asynchronously with the sequence scan, data inconsistency may occur.
To prevent data inconsistency, set the number of devices sampled at one time within the access units, or use high speed
sampling.
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