Refresh Cycle - Mitsubishi Electric MELSEC iQ-R Series User Manual

Station-based block data assurance
This method assures cyclic data for each station by handshake between this product and a network module for a link refresh.
For details on functions of the station-based block data assurance, refer to the manual of each network module.
MELSECWinCPU module
device
Data assurance
Station No.1
Data assurance
Station No.2
Data assurance
Station No.3
Data assurance Station No.4
■Access by a user program
Link refresh and device access from a user program are performed asynchronously.
To read and write the assured station-based block data, satisfy the following conditions:
• Refresh devices on the CPU side are assigned continuously to one device.
• Data is read/written from/to devices in a batch to access internal user devices.
*1 To read or write data from/to devices in a batch, use the mdBdSendEx, mdBdReceiveEx, mdBdRandWEx, or mdBdRandREx function.
Only up to 65,000 bytes can be accessed per time. To access a device with the size exceeding 65,000 bytes, create an interlock
program. Note that using any of the following functions may cause data inconsistency: the mdSendEx, mdReceiveEx, mdRandWEx,
mdRandREx, mdRandRLabelEx, and mdRandWLabelEx functions.
Interlock program
This method assures data of more than 32 bits without using the station-based block data assurance setting.
Define devices for handshake and read or write data from/to devices by setting the defined devices as a link refresh target and
handshaking with other stations.

Refresh cycle

Link refresh with a network module is performed in the refresh cycle of the fixed cycle processing function.
For the length of time for link refresh in each network module, refer to the following:
Page 172 Processing Time
Network module
link device
Station No.1 Data assurance
Station No.2 Data assurance
Link refresh
Station No.3 Data assurance
Station No.4
Data assurance
*1
16 NETWORK MODULE ACCESS FUNCTION
16.1 Cyclic Transmission
16
163