Fieldbus Register Table
Created by NodeFileCreator V2.7 (wv) on 08/06/11 at 14:57:05
FIELDBUS REGISTER TABLE FORMAT RULES
This document lists all of the available registers for the control unit with the abovementioned software. The registers are described using a fixed format. Below is a detailed explanation of the various elements that describe any given register.
Register Name:
This is the name of the register, of which there are four basic types. The first three letters of the register name define the register type and or operation that can be performed. The rest of the name simply describes which particular bit of data is involved.
Available Function:
This defines the type of operation that can be performed. The possible operation types are: “Read data” and “Write data”.
Available Register Range: (always in hexadecimal notation)
This defines the range of the data block the register is part of. It shows the start address of the data block (first register: XXXX) and the end of the data block (last register:YYYY) in the format: XXXX...YYYY. Note: in case the registers are part of a”broadcast” (Adv) data block or are part of the range 4000....5FFF it is always possible to request individual (minimum 1 word) or partial sections of the data block.
Max Register Length: (always in hexadecimal notation)
This defines the maximum data size (number of register) in the overall data block.
Register Address (always in hexadecimal notation)
This defines the actual register address to access the register. In case the FIELDBUS being used is MODBUS RTU the register addresses are exactly the same as "MODBUS holding register addresses". In case of PROFIBUS DP, DEVICENET or other fieldbusses the register adresses are simply numerical identifiers for the various data items.
Register Length: (always in hexadecimal notation)
This defines the fundamental size of the data at the actual register address. It is shown as number of registers (16 bit words) and/or the number of bytes.
Just below the “Register Length” entry there is either a description of the “DATA-TYPE”, “DATA-CONVERSION” or additional comments to describe the structure of the data in more detail.
Descriptions of the various “DATA-TYPE” and “DATA-CONVERSION” items can be found at the bottom of this document.
General terms used in this document
MSB: Most Significant Byte (always the “high order” byte in a 16 bit word => also the “first” byte)
LSB: Least Significant Byte (always the “low order” byte in a 16 bit word => also the “second” byte)
FIELDBUS REGISTER TABLE DATA ACCESS RULES
In principle accessing the data within a data block is only possible when using the full data block size.
Example: the “GetStatus” request for a compressor always produces 3 data words. When requesting the data it is necessary to always request the data as 3 word data block, otherwise the data cannot be read.
The only exceptions to th e rule are “broadcast” (Adv) data blocks (all controller models) and register addresses within the range 4000...5FFF. For those data blocks it is possible to read individual data elements within the data block. Any request for data that falls within the specified data block range is acceptable. Write operations are only possible using the full data block size
Example: a basic sequencer unit broadcast data block which contains 7 individual registers:
- Register F020: AdvAvailableStatus
- Register F021: AdvRunningStatus
- Register F022: AdvLoadedStatus
- Register F023: AdvAlarmStatus
- Register F024: AdvSystemStatus
- Register F025: AdvTargetPressure
- Register F026: AdvSystemPressure
To access data within this data block it is possible to:
- Request each individual register (always 1 word).
- Ask for two subsequent registers (e.g: F021 & F022)
- Ask for any set of registers within the block.
- Ask for the entire data block (F020...F026) with a single request.
The only basic rule is that the data should be requested in such a way that the combination of register start address + number of registers does not exceed the last register address, e.g.: the gateway will not accept a request starting at address F025 with a length of 3 registers.
FIELDBUS REGISTER TABLE
FIELDBUS REGISTER DETAILS。