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8-1
Section
Remote I/O Communications Characteristics
152
8-1
Remote I/O Communications Characteristics
This section describes the characteristics of PROFIBUS-DP communications
when OMRON Master and Slave Units are being used. Use this section for
reference when planning operations that require precise I/O timing.
The equations provided here are valid under the following conditions:
1, 2, 3...
1. The Master Unit is configured properly.
2. All of the required Slaves are participating in communications.
3. No errors are being indicated at the Master Unit
4. Messages are not being produced in the Network.
Note
1. The values provided by these equations may not be accurate if another
company’s Master or Slave is being used in the Network.
2. This manual only refers to parts related to the MULTIPLE I/O TERMINAL.
8-1-1 I/O Response Time
The I/O response time is the time it takes from the reception of an input signal at
an Input Slave (MULTIPLE I/O TERMINAL Input I/O Unit) to the output of the
corresponding output signal at an Output Slave (MULTIPLE I/O TERMINAL
Output I/O Unit).
Minimum I/O Response Time
The minimum I/O response times are the I/O response times shown in the
following diagram.
Peripheral servicing cycle time
PROFIBUS-DP Master Unit
PRT1-COM Communication Unit
PROFIBUS-DP I/O response
time
Input Unit
Output Unit
PC
T
IN
:
Input I/O Unit ON (OFF) delay time
T
OUT
:
Output I/O Unit ON (OFF) delay time
T
RT-IF
:
I/O Unit interface communications time (1.5 ms)
T
RT-IN
:
Communications time for 1 Input Slave
T
RT-OUT
: Communications time for 1 Output Slave
(With the MULTIPLE I/O TERMINAL, T
RT-IN
and T
RT-OUT
will be the
communications time per Slave.)
The minimum I/O response time (T
MIN
) is the total of the following terms:
T
MIN
= T
IN
+ T
RT-IF
+ (PROFIBUS-DP I/O response time) + T
RT-IF
+ T
OUT
Note
For details on the Input I/O Unit input delay time and the Output I/O Unit output
delay time, see information on the I/O Units in 6-1 Common Specifications for
Basic I/O Units.
Note
Refer to the PC’s Operation Manual for details on the PC’s cycle time.