IDEC MICROSmart FC6A-C16K1CE, Руководство по связи, Страница: 168 / 252

7: D
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OMMUNICATION
7-10 FC6A S
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ANUAL
FC9Y-B1730
Data Refresh
In the data link communication, the master station communicates with only one slave station in one communication cycle. When a
slave station receives a communication from the master station, the slave station returns data stored in data registers assigned for
data link communication. After receiving data from slave stations, the master station stores the data into data registers allocated
to each slave station. The process of updating data into data registers is called refresh. When the maximum 31 slave stations are
connected, the master station requires 31 communication cycles to communicate with all slave stations.
Both master and slave stations refresh communication data at the END processing. When data refresh is complete, communication
completion special internal relays M8080 through M8116 (slave station communication completion relay) go on at the master
station for one scan time after the data refresh. At each slave station, special internal relay M8080 (communication completion
relay) goes on.
When the master station completes communication with all slave stations, special internal relay M8117 (all slave station
communication completion relay) goes on at the master station for one scan time.
Total Refresh Time at Master Station for Communication with All Slave Stations (Trfn)
The master station requires the following time to refresh the transmit and receive data for communication with all slave stations,
that is the total of refresh times.
[Baud Rate 19,200 bps] Trfn =  Trf =  {4.2 ms + 2.4 ms
×
(Transmit Words + Receive Words) + 1 scan time}
[Baud Rate 38,400 bps] Trfn =  Trf =  {2.2 ms + 1.3 ms
×
(Transmit Words + Receive Words) + 1 scan time}
[Baud Rate 57,600 bps] Trfn =  Trf =  {1.6 ms + 0.9 ms
×
(Transmit Words + Receive Words) + 1 scan time}
Refresh Time
When data link communication is performed with such parameters as transmit words 6, receive words 6, slave stations 8, and
average scan time 20 ms, then the total refresh time Trf8 for communication with all eight slave stations will be:
[Baud Rate 19,200 bps] Trf8 = {4.2 ms + 2.4 ms
×
(6 + 6) + 20 ms}
×
8 = 424.0 ms
[Baud Rate 38,400 bps] Trf8 = {2.2 ms + 1.3 ms
×
(6 + 6) + 20 ms}
×
8 = 302.4 ms
[Baud Rate 57,600 bps] Trf8 = {1.6 ms + 0.9 ms
×
(6 + 6) + 20 ms}
×
8 = 259.2 ms
Data Link with Other PLCs
The FC6A Series MicroSmart can exchange data by communicating with IDEC FC4A Series and FC5A Series MicroSmart (data link).
Data Link with FC4A/FC5A
Mode Separate Refresh Mode
Scan Time
Since the communication between the master station and slave stations proceeds independently of the
user program scanning, the scan time is not affected.
Data Refresh Timing
At both master and slave stations, received data is refreshed at the END processing. Refresh completion
can be confirmed with communication completion special internal relays M8080 through M8117.
Applicable Master Station FC6A Series MicroSmart (FC4A/FC5A MicroSmart)
Applicable Slave Station FC6A Series MicroSmart (FC4A/FC5A MicroSmart)
FC4A/FC5A Settings MicroSmart Settings
Transmit data: 6 words
Receive data: 6 words
Baud rate: 19,200 or 38,400 bps
Set the data link station slave station to 1 to 31.
Master Station
Slave Station 1 (FC6A Series MicroSmart) Slave Station 31
FC4A/FC5A