Emerson RSTi-OM - Multiple Port Process Data (PDI;PDO) Access via Modbus;TCP

RSTi-OM User Manual Section 11
GFK-3212A Jun 2021
Modbus/TCP Interface
113
11.3 Multiple Port Process Data (PDI/PDO) Access via
Modbus/TCP
The process data have been grouped together to minimize the number of Modbus messages required
to interface to the IO-Link master. The PDI and PDO data for multiple ports can be received or
transmitted by one message.
To receive and transmit process data for eight ports, it may be necessary to adjust the size of the
PDI/PDO data blocks.
Modbus Read/Write Access where:
• All PDI data can be read with one Modbus Read Holding Registers message.
• All PDO data can be read with one Modbus Read Holding Registers read the message.
• All PDO data can be written with one Modbus Write Holding Registers message.
Starting Modbus Holding Register
Address (base 1)
IO-Link Port 1 IO-Link Port 2 IO-Link Port 3 IO-Link Port 4 Length
1000 Data length = Port 1 to Port 4
2000 Data length = Port 2 to Port 4
3000 Data length = Port 3 to Port 4
4000 Data length = Port 4
Starting Modbus Holding Register
Address (base 1)
IO-Link Port 1 IO-Link Port 2 IO-Link Port 3 IO-Link Port 4 Length
1050 Data length = Port 1 to Port 4
2050 Data length = Port 2 to Port 4
3050 Data length = Port 3 to Port 4
4050 Data length = Port 4
Starting Modbus Holding Register
Address (base 1)
IO-Link Port 1 IO-Link Port 2 IO-Link Port 3 IO-Link Port 4 Length
1050 Data length = Port 1 to Port 4
2050 Data length = Port 2 to Port 4
3050 Data length = Port 3 to Port 4
4050 Data length = Port 4
Starting Modbus Holding Register
Address (base 1)
IO-Link Port 5 IO-Link Port 6 IO-Link Port 7 IO-Link Port 8 Length
5000 Data length = Port 5 to Port 8
6000 Data length = Port 6 to Port 8
7000 Data length = Port 7 to Port 8
8000 Data length = Port 8
Starting Modbus Holding Register
Address (base 1)
IO-Link Port 5 IO-Link Port 6 IO-Link Port 7 IO-Link Port 8 Length
5050 Data length = Port 5 to Port 8
6050 Data length = Port 6 to Port 8
7050 Data length = Port 7 to Port 8
8050 Data length = Port 8
Starting Modbus Holding Register
Address (base 1)
IO-Link Port 5 IO-Link Port 6 IO-Link Port 7 IO-Link Port 8 Length
5050 Data length = Port 5 to Port 8
6050 Data length = Port 6 to Port 8
7050 Data length = Port 7 to Port 8
8050 Data length = Port 8
Read (Input) Process Data Input
Read (Input) Process Data Output
Write (Output) Process Data Output
Read (Input) Process Data Input
Read (Input) Process Data Output
Write (Output) Process Data Output