Data Dictionary - Hach Anatel PAT700 User Manual

Modbus Protocol

11.3.1 Data dictionary

Page 152
The following tables detail the Modbus addresses required to access each item of the
public data.
Addressing (0 or 1 Based)
The addressing within the Modbus/TCP protocol (that is, the data within the physical
packet) is 0-based, meaning the first element/item to be accessed is referenced by
address 0. The Modbus standard for handling and displaying the data is 1-based;
meaning the first element/data item to be access is referenced by address 1.
Most client applications handle this by having the user enter the 1-based number, and
then subtract 1 to revert to the 0-based addressing required at the protocol level.
Some client applications allow the user to enter the 0-based number, or a combination,
depending on how it is configured.
The addresses defined within the following table are 1-based, as the majority of the client
applications work with this method.
Identification Block
The Identification Block registers consists of basic information about the instrument.
These registers are read-only and are updated by the instrument during the initial
power-on sequence. In addition, these registers are only configurable at the factory and
by qualified field service personnel.
Note: Use FC16 where '*' is indicated.
Address Register Description
0000 Manufacturer ID
0015 Model Number
0025 Serial Number
0030 Secondary ID
0034 Last Calibration Date
0036 Calibration Due Date
0038 Firmware Version
0039 Hardware Version
0040-0099 Future Expansion
Address 0-14 (Manufacturer Identification) (Format: Strings)
Get the instrument's Manufacturer ID. The ID consists of 30 bytes of printable ASCII
characters (0x20-0x7E). A register byte value of 0x00 or word value of 0x0000 indicates
the end of the Manufacturer ID.
Address 15-24 (Model Number) (Format: Strings)
Get the model number. The model number consists of 20 bytes of printable ASCII
characters (0x20-0x7E). A register byte value of 0x00 or word value of 0x0000 indicates
the end of the model description.
Identification Block
Size
Access
(Words)
R 15
R 10
R 5
R 4
R 2
R 2
R 1
R 1