Configuring Modbus Communication; Modbus-Specific System Objects - Siemens SIMATIC TIM 3V-IE DNP3 System Manual

6.6.14

Configuring MODBUS communication

Differences in the configuration of MODBUS communication
Since MODBUS slaves are not SIMATIC devices or stations they are not configured as
stations in STEP 7 nor are they configured as destination subscribers. Connections to
MODBUS slaves are therefore also not configured in the connection configuration.
Configuring MODBUS communication
MODBUS communication is configured in the areas and objects of the subscriber
administration listed below:
1. Select the "TIMs with TD7onTIM" directory.
2. Select a TIM in the subscriber list.
Parameters of the MODBUS polling cycle of the CPU of this station are set in the
parameter area.
3. Select a DNP3 TIM in the "TIMs with TD7onTIM" directory.
4. Open the TD7onTIM library and insert the MODBUS-specific objects.
The following MODBUS-specific objects are inserted from the TD7onTIM library for a TIM
with TD7onTIM:
● System object "ModbusGateway"
The use of the MODBUS protocol for the serial interface of the DNP3 TIM is specified
using the "ModbusGateway" object. The interface and parameters of the connection to
the MODBUS slaves are configured with this object.
● System object "ModbusPartnerStatus"
The object signals the reachability of the MODBUS slave to the CPU.
● Data object "ModbusWrite"
Writes data from the configured input memory area of the CPU to a MODBUS slave.
● Data object "ModbusRead"
Reads data from a MODBUS slave and writes this to the configured output memory area
of the CPU.
The objects are described in the sections that follow.
6.6.14.1

MODBUS-specific system objects

ModbusPartnerStatus
The optional object "ModbusPartnerStatus" is used to monitor the reachability of the
connected MODBUS slaves. The status is made available to the CPU in an output byte. One
bit per communications partner is reserved in the output byte to indicate the status of the
partner:
TIM DNP3
System Manual, 12/2015, C79000-G8976-C253-04
The SINAUT Configuration Tool
6.6 TD7onTIM
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