Chapter5 Processing Time Of Qcpu In Multiple Cpu System 5-1 To; Concept Of Scan Time - Mitsubishi Electric MELSEC Q Series User Manual

CHAPTER5 PROCESSING TIME OF QCPU IN MULTIPLE

5.1 Concept of Scan Time

The concept of scan time in the multiple CPU system is the same as that in the single CPU system.
This chapter describes how to calculate the processing time when the multiple CPU system is configured.
(1) I/O refresh time
I/O refresh time is calculated with the equation explained in the following manual.
User's Manual (Function Explanation, Program Fundamentals) for the CPU module used.
The I/O refresh time is prolonged by the following values when it is overlapped with bus access from/to other
CPUs.
(Extension time) =
Use the value in Table5.1 for N3.
Q00CPU
Q01CPU
Q02CPU
Q02HCPU, Q06HCPU, Q12HCPU, Q25HCPU
Q02PHCPU, Q06PHCPU, Q12PHCPU,
Q25PHCPU
Q00UCPU, Q01UCPU, Q02UCPU,
Q03UDCPU, Q04UDHCPU, Q06UDHCPU,
Q10UDHCPU, Q13UDHCPU, Q20UDHCPU,
Q26UDHCPU, Q03UDECPU, Q04UDEHCPU,
Q06UDEHCPU, Q10UDEHCPU,
Q13UDEHCPU, Q20UDEHCPU,
Q26UDEHCPU
(2) Total value of instruction execution time
Refer to the following manual for details on the processing time of instructions dedicated to the multiple CPU
system, and various processing times of instructions used in the multiple CPU system.
QCPU Programming Manual (Common Instructions)
5 - 1
CPU SYSTEM
(No. of input points + No. of output points)
Table5.1 Extension of I/O refresh time
QCPU
N3
16
Systems with only a main
base unit
8.7 s
(No. of other CPUs) (µs)
N3
Systems that include
additional base units
21 s