Calculating Guidelines For I/O Response Times - Omron CJ1W-DRM21 Operation Manual

8-1-2

Calculating Guidelines for I/O Response Times

This section describes the formulas to use to calculate the minimum and maximum I/O response times
for the following configuration. Refer to 8-1-1 Communications Cycle Time for the communications cycle
time and the communications time per slave, which are used in the formulas.
User program
IN1
OUT1
IN1
OUT1
Precautions for Safe Use
Actual I/O response times depend on the number of CJ-series Units that you use, the size of I/O
data that is refreshed for other CPU Bus Units, and other factors. The values that are calculated
with these formulas are guidelines only. You must always check performance under actual condi-
tions with the actual hardware and make sure that suitable I/O response times are achieved.
Formula for the Maximum I/O Response Time
You can calculate the maximum I/O response time T
T = T + T
MAX IN RM
T : Input slave ON or OFF delay (ms)
IN
T : Communications cycle time (ms)
RM
N : Number of communications cycles of the DeviceNet Unit that waits for data to return from the
RMMAX
CPU Unit
T : Communications time per slave for output slaves (ms)
RT-OUT
T : Output slave ON or OFF delay (ms)
OUT
CJ-series DeviceNet Units Operation Manual for NJ-series CPU Unit(W497)
NJ-series CPU Unit
DeviceNet
Input slave
IN1
I/O response time
× 2 + N × T
+ T
RMMAX RM
DeviceNet
Output slave
OUT1
(ms) with the following formula.
MAX
+ T
RT-OUT OUT
8 Communications Timing
8
8-5