I/O Response Time - Omron CPM1 - PROGRAMING MANUAL 02-2001 Programming Manual

CPM2A/CPM2C Cycle Time and I/O Response Time
Cycle Time Example
Process
1. Overseeing
2. Program execution
3. Cycle time calculation
4. I/O refreshing
5. Peripheral port servicing
Cycle time

8-2-2 I/O Response Time

524
In this example, the cycle time is calculated for a CPM2A/CPM2C CPU Unit with
30 I/O points (18 input points and 12 output points). The I/O is configured as fol-
lows:
18 inputs: 2 words (00000 to 00011, 00100 to 00105)
12 outputs: 2 words (01000 to 01007, 01100 to 01103)
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:
The average processing time for a single instruction in the user's program is as-
sumed to be 1.26 s. The cycle times are as shown in the following table.
Calculation method
Fixed
1.26 500 ( s)
Negligible
Fixed
Minimum time
(1) + (2) + (3) + (4) + (5)
Note 1. The cycle time can be read from the PC via a Programming Device.
2. The maximum and current cycle time are stored in AR 14 and AR 15.
3. The cycle time can vary with actual operating conditions and will not neces-
sarily agree precisely with the calculated value.
The I/O response time is the time it takes after an input signal has been received
(i.e., after an input bit has turned ON) for the PC to check and process the in-
formation and to output a control signal (i.e., to output the result of the proces-
sing to an output bit). The I/O response time varies according to the timing and
processing conditions.
The minimum and maximum I/O response times are shown here, using the fol-
lowing program as an example.
The following conditions are taken as examples for calculating the I/O response
times.
Input ON delay:
Overseeing time:
Instruction execution time:
Output ON delay:
Communications ports:
Variable (no minimum set)
Time with
Programming Device
0.3 ms
0.6 ms
0 ms
0.3 ms (CPM2C: 0.06 ms)
0.55 ms
1.75 ms (CPM2C: 1.51 ms)
Input
10 ms (input time constant: default setting)
1 ms (includes I/O refreshing)
14 ms
15 ms
Not used.
Section
Time without
Programming Device
0.3 ms
0.6 ms
0 ms
0.3 ms (CPM2C: 0.06 ms)
0 ms
1.2 ms (CPM2C: 0.96 ms)
Output
8-2