6. COMMUNICATION TIME
MELSEC-A
6-5
6.2
Transmission Delay Time When There are Multiple Master
Stations
The follow explains the transmission delay time when multiple master stations are connected to the
same network.
The following diagram (Fig. 6.2) shows the example where two master stations are connected to the
same network.
Bc(1) and Bc(2) in the following diagram (Fig. 6.2) are the bus cycle times of the master station 1 and
master station 2, respectively, and their transmission delay time is calculated using the formula
presented in Section 6.1.
Master 1 executes polling
Master 2 executes polling
Master 1 executes polling
Time
Master station 1's
bus cycle time Bc
(1)
Master station 2's
bus cycle time Bc
(2)
Ls
Fig. 6.2
The transmission delay time when multiple masters are connected
As shown in this diagram, each master 1 link scan time is calculated as:
Number of the master stations
Ls =
∑
Bc (n)
n = 1