Sensor Administration Under Modbus - wtw DIQ/S 182-MOD System Operating Manual

Modbus connection
Query and response
telegram
Supported
Modbus commands
Creating the assignment
of sensor numbers
7 - 6
Data transmission takes place via query and response telegrams. The
form of the telegrams is determined by the Modbus RTU protocol.
The Modbus master transmits a query telegram with a Modbus
command to the Modbus slave (here, the DIQ/S 182-MOD). The
Modbus slave transmits a response telegram with the requested data
from the sensor data block or an error message.
The DIQ/S 182-MOD provides the data block for read access only.
Writing Modbus commands are not carried out.
Modbus commands
Read Input Register
Read Discrete Inputs
Read Holding Register
Read Coils

7.4.2 Sensor administration under Modbus

Preparation of the IQ S
may require, e.g. the following:
 Creating an IQ S
ENSOR
sensor numbers to sensors
 Creating several IQ S
assignment of sensor numbers to sensors
 Changing the order of the sensors in an already installed system
You want to install an IQ S
create a specific sequence of sensor number assignments to the
sensors.
1 Carry out a system start without any sensors (see section
3.10).
2 Connect the sensors to the system in the required order. With
each sensor wait until the system has recognized the sensor.
Command code
04h
02h
03h
01h
N for communication with the Modbus
ENSOR ET
N system with specific assignment of
ET
N systems with the identical
ENSOR ET
N system and, at the same time,
ENSOR ET
System 182
ba75504e07 04/2012