Calculation Example For Time Increase Of Scan Time - Mitsubishi Electric QJ81DL96 User Manual

17
PROCESSING TIME

17.3.3 Calculation example for time increase of scan time

The following shows a calculation example for time increase of scan time in high speed
data sampling.
For details of formulas and constants regarding time increase of scan time, refer to Section
17.3.1.
(1) Sampling condition
Access target CPU
Data logging setting
(2) Calculation of time increase of scan time
Item
Programmable controller
CPU
Network
Logging type
Sampling
Data logging amount
(a) Calculation regarding Constant K1 (K1 X N)
• Bit device M (10 point worth)
0.59 (us)  10 (points) = 5.9 [us]
• Word device D (20 point worth)
0.33 (us)  20 (points) = 6.6 [us]
• File register R (16 point worth)
0.35 (us)  16 (points) = 5.6 [us]
(K1  N) can be obtained by calculating the above values, as shown below.
5.9 (us) + 6.6 (us) + 5.6 (us) = 18.1 [us]
(b) Calculation regarding Constant K2 (K2  M)
• K2 value for Bit device M: 45 [us]
• K2 value for Word device D: 40 [us]
• K2 value for File register R: 40 [us]
The above worst value (45 [us]) is used for K2 and (K2 X M) can be obtained as
shown below.
45 (us)  1 (set number of high speed data samplings) = 45 [us]
(c) Calculation regarding Constant K3 (K3)
• K3 value for Bit device M: 65 [us]
• K3 value for Word device D: 45 [us]
• K3 value for File register R: 48 [us]
The above worst value (65 [us]) is used for K3.
The time increase of scan time can be obtained by calculating the above values
(a), (b), and (c), as shown below.
18.1 (us) + 45 (us) + 65 (us) = 128.1 [us]
17.3.3 Calculation example for time increase of scan time
Description
Q04UDHCPU
(High speed data logger module is mounted in the main base unit.)
Own station (single CPU configuration)
Trigger logging
Data logging 01: high speed data sampling (each scan)),
sampling consecutive devices.
Device M: 10 points
Device D: 20 points
Device R: 16 points
17.3 Effect on Sequence Scanning Time
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18
A
I
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