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Data Link I/O Response Time
Section 8-3
CS/CJ-series, CVM1, or CV-series PLC Under Synchronous Operation, C200HX/HG/HE
PLC, or CQM1H-series PLC
Maximum Data Link I/O
Response Time
There are three points shown in the diagram above where processing is
delayed, increasing the data link I/O response time.
1,2,3...
1.
The input arrives in the PLC just after I/O refreshing, causing a delay of up
to one cycle before the input is read into the PLC.
2.
Data exchange occurs just after the PLC at node #1 passes the token,
causing a processing delay of up to one communications cycle time until
the next token is received. There is a maximum delay of one communica-
tions cycle after the token is received.
3.
At node #7, data from the previous data exchange is still being transferred,
causing a delay of up to one cycle before the input is read into the PLC. (If
the cycle time at node #7 is longer than the communications cycle time, the
processing will be delayed for two cycles.) Also, if the total number of data
link words exceeds the maximum number for a single exchange, the data
exchange will be divided up and there may be a delay of one to two addi-
tional cycles.
The maximum number of words that can be exchanged in a single data ex-
change is approx. 7,800 words for CS/CJ-series PLCs, approx. 3,700
words for CVM1 and CV-series PLCs, approx. 4,000 for C200HX/HG/HE
PLCs, and approx. 1,200 words for CQM1H-series PLCs.
The equation for maximum data link I/O response time is as follows:
Note
The PLC cycle time when data link words exceed 12,000 using a CS/CJ-
series Controller Link Unit with unit version 1.2 or later is calculated as fol-
lows.
Input device
Program
Program
Input
Input ON delay
1 cycle
Output
Output device
Output ON delay
1 cycle
Communications
cycle time
Data link transmission
PLC at node #7
I/O refresh
Data exchange
PLC at node #1
Data link I/O response time
Input ON delay
1.5 ms
Cycle time of PLC at node #1
×
2
25 ms
×
2
Communications cycle time
×
2
22 ms
×
2
PLC cycle time at node #7
×
2 (See note.)
10 ms
×
2 (See note.)
Output ON delay
15 ms
Total (data link I/O response time)
130.5 ms
Summary of Contents for C200HW-CLK21
Page 3: ...iv ...
Page 9: ...x ...
Page 12: ...xiii TABLE OF CONTENTS Index 367 Revision History 373 ...
Page 13: ...xiv ...
Page 19: ...xx ...
Page 57: ...32 Application Precautions Section 1 5 Example CX Programmer Response Timeout Setting ...
Page 69: ...44 Message Service Procedure Section 2 2 ...
Page 111: ...86 Constructing Networks with Repeater Units Section 3 4 ...
Page 154: ...129 Setting Data Links Section 5 2 Device Information Setting Data Link Tables ...
Page 261: ...236 Response Codes Section 6 7 ...
Page 297: ...272 Message Delay Times Section 8 4 ...
Page 353: ...328 Handling Precautions Section 9 6 ...
Page 364: ...339 Changing the Data Link Tables with Active Data Links Section 10 2 ...
Page 365: ...340 Changing the Data Link Tables with Active Data Links Section 10 2 ...
Page 369: ...344 Standard Models Appendix A ...
Page 391: ...366 Using the Relay Terminal Block Appendix C ...
Page 397: ...372 Index ...
Page 401: ...376 Revision History ...