Omron C200H-LK401 Manuel D’Utilisation

IORF(97) can be used in programming to shorten the I/O response time
greater than is possible by setting a high number of refresh bits. (Remember,
increasing the number of refresh bits set on the back-panel LED shortens
response time, but increases the scan time of the PC.) The following calcula-
tions for the maximum scan time use the same example System configura-
tion as that used in 6-1 Response Times. In programming the PCs for PC
Link Units #0 and #7, IORF(97) is executed during every PC scan for the PC
Link Units. The basic equation for the maximum I/O response time is as fol-
lows:

Response time = input ON delay + [scan time of PC of Unit 0 x (number of

LR transfer bits 

÷

 number of I/O refresh bits 

÷

 2)] + alpha +

PC Link scan time + invitation sequence processing time +
{scan time of PC of Unit 7 x [(number of LR transfer bits 

÷

number of I/O refresh bits 

÷

 2) x 2 + 1]} + beta + output ON

delay

If scan time of PC of Unit 0 > PC Link scan time, alpha = scan time of PC of
Unit 0. If scan time of PC of Unit 0 < PC Link scan time, alpha = PC Link
scan time.

If scan time of PC of Unit 7 > PC Link scan time, beta = scan time of PC of
Unit 7. If scan time of PC of Unit 7 < PC Link scan time, beta = PC Link scan
time.

The required data from the example System configuration is as follows:

Input ON delay

 1.5 ms

Output ON delay

 15 ms

Scan time of PC of Unit 0

 20 ms + 5.7 ms = 25.7
(required for IORF execution)

Scan time of PC of Unit 7 

 50 ms + 5.7 ms = 55.7
(required for IORF execution)

Number of PC Link Units

 8

Number of LR bits

 1,024

Number of refresh bits for Unit 0

 256

Number of refresh bits for Unit 7

 256

PC Link scan time

 32.4 ms

Invitation sequence processing time  0 ms

Placing these values into the equation produces a maximum I/O response
time of 466.9 ms, approximately 200 ms shorter than that obtained for the
same I/O example in 6-1 Response Times.