Hamilton-sundstrand-company Fuel Metering Valves XVG Manuel d'utilisateur télécharger pdf (Page 6)

7.2 Modbus Transactions

The slave’s response message is also constructed using Modbus protocol. It

contains fields confirming the action taken, any data to be returned, and an error–

checking field.

If an error occurred in receipt of the message, or if the slave is unable to perform

the requested action, the slave will construct an error message and send it as its

response.

Request

FUNCTION CODE + REQUEST DATA

Response, no error

FUNCTION CODE + RESPONSE DATA

Response, with error

EXCEPTION FUNCTION CODE + REQUEST DATA

where

EXCEPTION FUNCTION CODE = (FUNCTION CODE + 0x80)

Table 2: Modbus Transactions

7.3 Modbus Register Types

Each Modbus register in the XVG/eXVG is identified by its 4-digit number

address. With XVG/eXVG, the term “register” refers to both Modbus Holding

Registers (read-write) and Modbus Input registers (read-only). The types of

XVG/eXVG Modbus registers are listed in Table 3.

Type

Size Data Type

Address

Range

Description

U16 16 bit Integer

3000-

3999

Unsigned 16-bit integers ranging

from 0 to 65535.

U32 16 bit Integer

5000-

6999

Use in pairs to store unsigned 32-bit

integers ranging from 0 to

4294967295.

Float 16 bit Floating-point

7000-

7999

Use in pairs to store 32-bit floating-

points values in single-precision

IEEE 754 format.

ASCII 16 bit 8-bit ASCII

3000-

3999

One or more consecutive registers.

Each register stores two 8-bit ASCII

characters (16 bits total).

Table 3: Modbus Transactions

1 2 3 4 5 6 7 8 9 10 11 ... 35 36

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