491
The remote refresh time is 2.0 + (0.2×
a
) ms, where
a
is the number of words to
refresh. The communications cycle time is 5 ms or the sum total of the commu-
nications times of Slaves connected to the Master. The communications cycle
time can also be set in the SYSMAC BUS/2 settings in the PC Setup, refer to the
SYSMAC BUS/2 Remote I/O System Manual
for details. The following table lists
the communications times of the various Slaves.
Slave Transmission type Communications time
Group 1 Wired 0.16 ms
Optical 0.32 ms
Group 2 Wired 0.31 ms
Optical 0.47 ms
58M Wired 1.25 ms
Optical 1.89 ms
Group 3 54MH Wired 2.5 ms
Optical 4.5 ms
122M Wired 2.5 ms
Optical 4.5 ms
The data in the following table is used to produce the minimum and maximum
cycle times shown calculated below.
Input ON delay 1.5 ms
Cycle time 20 ms
Output ON delay 15 ms
Communications cycle time 5 ms (one group 3, 58M Slave)
Remote refresh time Approx. 2 ms
The PC responds most quickly when the Master receives the input signal just
prior to SYSMAC BUS/2 refreshing and the relevant instruction is executed with-
in the communications cycle time. This situation is illustrated below.
Input signal
Output signal
Cycle
Cycle time
I/O refresh
I/O response time
Output ON delay
Input ON delay
Program
execution
Buffer in Master
Communications
cycle time
Minimum I/O response time = input ON delay
+ communications cycle time × 6 + remote refresh time
+ output ON delay
Minimum I/O response time = 1.5 + (5×6) + 2 +15 = 48.5 ms
Minimum I/O Response
Time
I/O Response Time Section 6-5
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