Operating Instructions
J22 TDLAS Gas Analyzer
58
Hauser
6.4
Modbus data map
Function of the Modbus data map
The device offers a special memory area, the Modbus data map (for a maximum of 16 device parameters), to allow
users to call up multiple device parameters through Modbus RS485 or Modbus TCP and not only individual device
parameters or a group of consecutive device parameters. Modbus TCP/IP clients and servers listen and receive
Modbus data through port 502.
Grouping of device parameters is flexible and the Modbus client can read or write to the entire data block
simultaneously with a single request telegram.
Structure of the Modbus data map
The Modbus data map consists of two data sets:
•
Scan list: Configuration area.
The device parameters to be grouped are defined in a list in that their Modbus
RS485 or Modbus TCP register addresses are entered in the list.
•
Data area.
The measuring device reads out the register addresses entered in the scan list cyclically and writes
the associated device data (values) to the data area.
6.4.1
Scan list configuration
For configuration, the Modbus RS485or Modbus TCP register addresses of the device parameters to be grouped must
be entered in the scan list. Please note the following basic requirements of the scan list:
Max. entries
16 device parameters
Supported device parameters
Only parameters with the following characteristics are supported:
•
Access type: read or write access
•
Data type: float or integer
Configuring the scan list through Modbus RS485 or Modbus TCP
Carried out using register addresses 5001 – 5016
Scan list
No.
Modbus RS485 or Modbus TCP register
Data type
Configuration register
0
Scan list register 0
Integer
Scan list register 0
. . .
. . .
Integer
15
Scan list register 15
Integer
Scan list register 15
6.4.2
Reading out data through Modbus RS485 or Modbus TCP
The Modbus client accesses the data area of the Modbus data map to read out the current values of the device
parameters defined in the scan list.
Client access to data area
From register addresses 5051 to 5081
Содержание SpectraSensors J22 TDLAS
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