Data Logger - WIKA GDT-20 Manual De Instrucciones

5. Commissioning, operation

5.4.2.3 Data logger

The data logger is used for recording measured values over a certain time span.
EN
After setting up COM ports, the baud rate and the min./max. address or interval, the recor-
ding can be started. For continuous recording, it is possible to record the measured data
in the selected interval in a text file divided by tabs.
The recording is started with the green start symbol. Stop the recording using the red
stop symbol.
5.4.2.4 Modbus
The following documents (available under www.Modbus.org) are recommended for
understanding the Modbus
Modbus APPLICATION PROTOCOL SPECIFICATION
■
Modbus over Serial Line Specification and Implementation Guide
■
The register structure is described in the following.
Communication via messages
General form of the messages
Instrument address
8 bit
In accordance to Modbus
intermission of at least 3.5 characters.
The characters within one message may not have spacing of more than 1.5 characters.
Examples of a typical transmission:
Intermission Message 1 ▶ Intermission Message 2 ▶ Intermission Message 3 ...
38
register and functional description
®
architecture which the following chapters will refer to.
®
Function
8 bit
specification, separate messages must be divided by an
®
WIKA operating instructions transmitter, models GDT-20 and GDHT-20
Data
n x 8 bit
CRC check
16 bit