Omron GRT1 - 27-11-2006, Operation Manual

Page: 74 / 111

55
Remote Communication Characteristics
Section 3-5
3-5 Remote Communication Characteristics
3-5-1 I/O Communication Characteristics
This section describes the characteristics of PROFIBUS I/O communication
between a GRT1-PRT and an OMRON Master. Use this section for reference
when planning operations that require precise I/O timing.
The equations provided here are valid under the following conditions:
• All of the required Slaves are participating in communication.
• No errors are being indicated at the Master Unit.
• No third-party Master or Configurator is being used in the network.
Note This manual describes the communication with the SmartSlice I/O System
only. For details on the Master Unit or overall PROFIBUS network, refer to the
CS/CJ-series PROFIBUS DP Master Units Operation Manual (W409) .
I/O Response Time The I/O response time is the time it takes from the reception of an input signal
at an Input Unit in the SmartSlice I/O System to the output on an Output Unit
in the SmartSlice I/O System after being processed by the PLC program.
Minimum I/O Response
Time The minimum I/O response time (T
MIN
) is the total of the following terms:
T
MIN
= T
IN
+ T
SL-IN
+ T
SL-CI
+ T
RT-IN
+ (T
PLC
- T
RF
) + T
RT-OUT
+ T
SL-CI
+ T
SL-OUT
+ T
OUT
T
IN
: The Input Unit's ON (OFF) delay
T
OUT
: The Output Unit's ON (OFF) delay
T
SL-IN
: The SmartSlice bus' communication time (input data)
T
SL-OUT
: The SmartSlice bus' communication time (output data)
T
SL-CI
: The SmartSlice Communication Unit’s input data processing time
T
SL-CO
: The SmartSlice Communication Unit’s output data processing time
T
RT-IN
: The Input Slave's communication time/Slave
T
RT-OUT
: The Output Slave's communication time/Slave
T
RT
: The PROFIBUS communication time/Slave
T
PLC
: The PLC's cycle time
T
RF
: The PLC's PROFIBUS Unit refresh time
Note Refer to the GRT1 Series SmartSlice I/O Units Operation Manual for details
on Input Unit’s input delay times and Output Unit’s output delay times.
T
PLC
T
RF
T
RT-IN -
PLC
PROFIBUS
Communications Unit
SmartSlice bus
Input Unit
Output Unit
T
SL-CI -
T
SL-IN -
T
IN
T
RT-OUT -
T
SL- CO -
T
SL- OUT -
T
OUT