Omron CPM1 Programming Manual

411
CPM1/CPM1A Cycle Time and I/O Response Time Section 7-2
7-2-2 CPM1/CPM1A Cycle Time
The processes involved in a single CPM1/CPM1A cycle are shown in the fol-
lowing table, and their respective processing times are explained.
Note The percentage of the cycle allocated to peripheral port servicing can be
changed in the PC Setup (DM 6617).
Cycle Time and
Operations
The effects of the cycle time on CPM1/CPM1A operations are as shown
below. When a long cycle time is affecting operation, either reduce the cycle
time or improve responsiveness with interrupt programs.
Note 1. The PC Setup (DM 6655) can be used to disable detection of CYCLE TIME
OVER error.
2. The cycle monitoring time can be changed in the PC Setup (DM 6618).
Cycle Time Example In this example, the cycle time is calculated for a CPM1/CPM1A CPU Unit
with 20 I/O points (12 input points and 8 output points). The I/O is configured
as follows:
Inputs: 1 word (00000 to 00011)
Outputs: 1 word (01000 to 01007)
The rest of the operating conditions are assumed to be as follows:
User’s program: 500 instructions (consists of only LD and OUT)
Cycle time: Variable (no minimum set)
Process Content Time requirements
Overseeing Setting cycle watchdog timer, I/O bus check, UM
check, clock refreshing, refreshing bits allocated to
new functions, etc.
0.6 ms
Program execution User program is executed. Total time for executing instructions.
(Varies according to content of user’s
program.)
Cycle time calculation Standby until set time, when minimum cycle time is
set in DM 6619 of PC Setup.
Calculation of cycle time.
Almost instantaneous, except for
standby processing.
I/O refresh Input information is read to input bits.
Output information (results of executing program) is
written to output bits.
10-point CPU : 0.06 ms
20-point CPU: 0.06 ms
30-point CPU: 0.3 ms
Expansion I/O Unit 0.3 ms
Peripheral port servicing Devices connected to peripheral port serviced. 0.26 ms min., 5% or less of cycle time
up to 66 ms (see note)
Cycle time Operation conditions
10 ms or longer TIMH(15) may be inaccurate when TC 004 through TC 127 are used (operation will be normal for TC
000 through TC 003).
20 ms or longer Programming using the 0.02-second Clock Bit (SR 25401) may be inaccurate.
100 ms or longer TIM may be inaccurate. Programming using the 0.1-second Clock Bit (SR 25500) may be inaccurate.
A CYCLE TIME OVER error is generated (SR 25309 will turn ON). See note 1.
120 ms or longer The FALS 9F monitoring time SV is exceeded. A system error (FALS 9F) is generated, and operation
stops. See note 2.
200 ms or longer Programming using the 0.2-second Clock Bit (SR 25501) may be inaccurate.

Omron CPM1 Specifications

General

Brand	Omron
Model	CPM1
Category	Controller
Language	English