Omron CS1W-RPT01 Manuale Utente

The maximum data link I/O response time is calculated for four cases.

The following diagram illustrates the data flow that will produce the maximum
data link I/O response time when the cycle time of the PLC at nodes #1 and 7
are greater than the communications cycle time. 

There are four points shown in the diagram above where processing is
delayed, increasing the data link I/O response time.

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 that
makes it the polling node, causing a delay of up to one communications cy-
cle time before the data is transferred in data link processing.

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.

4.

The data transferred in data link processing arrives at the PLC at node #7
after data exchange, so the data will not be read into the PLC until the next
data exchange, causing a delay of up to 1 to 2 cycle.

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. 

Input device

Program

Program

Input

Input ON delay

1 cycle

Output

Output device

Output ON delay

1 cycle

Communications 
cycle time

Data link transmission

Controller Link Unit 
transmission processing

PLC at node #7

(1)

I/O refresh

Data exchange

Controller Link Unit 
transmission processing

PLC at node #1

Previous communica
tions cycle data

Data link I/O response time

(2)

(3)

(4)