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[KB430]64 bit floating point values using Open Modbus TCP/IP protocol

Tags: Modbus TCP/IP

Data acquisition
15 years ago
By ACHT
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Applies to:

PcVue version 8.2 SP2 and version 9.0 SP1.
The basic content of this article may also be applicable to other versions of PcVue although the detail may vary.
Summary:

This article explains how to retrieve 64 bit floating point values using the Open Modbus TCP/IP protocol.
Details:

For this method it is necessary to understand the format of, and directly edit, the variable definition file VAREXP.DAT.

1/ Declare a word frame (16 bits)

64_bits_floating

2/ Create EQT variables (3 variables in the sample) as shown in the screenshot below.

64_bits_floating2

3/ Map your variables every 4 words.

64_bits_floating3

4/ Stop the project and change the variable type directly in the varexp.dat file using a text editor.

 –          Original variable below (from file “original varexp.dat”):

 

REG,78,FRAME64,WORD0,,,,,,””,””,,,,,,E,0,0,0,0,0,1,0,0,0,0,,,1,MODBUS,PLC1,WORD_FRAME,U,0,0,16,,,,,,,,,,,,,,,,,,,,,,, ,0,0,65535,0,0,65535,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,””,””,””,,,””,””,,,,,,,,,,,,,,0,””,””,””,””,””,””,””,””,””,””,””,””,””,””,,,,,,,,,,,,0,0,,,0,,,,,,,,,,,,,,0,-1,-2,-2,0,””,,,,,,,,,,,,,,,,,,,,,,,,,,

 

REG,79,FRAME64,WORD2,,,,,,””,””,,,,,,E,0,0,0,0,0,1,0,0,0,0,,,1,MODBUS,PLC1,WORD_FRAME,U,8,0,16,,,,,,,,,,,,,,,,,,,,,,,,0,0,65535,0,0,65535,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,””,””,””,,,””,””,,,,,,,,,,,,,,0,,””,””,””,””,””,””,””,””,””,””,””,””,””,,,,,,,,,,,,0,0,,,0,,,,,,,,,,,,,,0,-1,-2,-2,0,””,,,,,,,,,,,,,,,,,,,,,,,,,,

 

REG,80,FRAME64,WORD3,,,,,,””,””,,,,,,E,0,0,0,0,0,1,0,0,0,0,,,1,MODBUS,PLC1,WORD_FRAME,U,16,0,16,,,,,,,,,,,,,,,,,,,,,,,,0,0,65535,0,0,65535,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,””,””,””,,,””,””,,,,,,,,,,,,,,0,””,””,””,””,””,””,””,””,””,””,””,””,””,””,,,,,,,,,,,,0,0,,,0,,,,,,,,,,,,,,0,-1,-2,-2,0,””,,,,,,,,,,,,,,,,,,,,,,,,,,

 

–          For PcVue to consider variables as 64 bits floating point values, you must change U to D

and 16 to 64  as shown below:

 

REG,78,FRAME64,FLOAT0,,,,,,””,””,,,,,,E,0,0,0,0,0,1,0,0,0,0,,,1,MODBUS,PLC1,WORD_FRAME,D,0,0,64,,,,,,,,,,,,,,,,,,,,,,,,0,0,65535,0,0,65535,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,””,””,””,,,””,””,,,,,,,,,,,,,,0,””,””,””,””,””,””,””,””,””,””,””,””,””,””,,,,,,,,,,,,0,0,,,0,,,,,,,,,,,,,,0,-1,-2,-2,0,””,,,,,,,,,,,,,,,,,,,,,,,,,,

 

REG,79,FRAME64,FLOAT1,,,,,,””,””,,,,,,E,0,0,0,0,0,1,0,0,0,0,,,1,MODBUS,PLC1,WORD_FRAME,D,8,0,64,,,,,,,,,,,,,,,,,,,,,,,,0,0,65535,0,0,65535,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,””,””,””,,,””,””,,,,,,,,,,,,,,0,””,””,””,””,””,””,””,””,””,””,””,””,””,””,,,,,,,,,,,,0,0,,,0,,,,,,,,,,,,,,0,-1,-2,-2,0,””,,,,,,,,,,,,,,,,,,,,,,,,,,

 

REG,80,FRAME64,FLOAT2,,,,,,””,””,,,,,,E,0,0,0,0,0,1,0,0,0,0,,,1,MODBUS,PLC1,WORD_FRAME,D,16,0,64,,,,,,,,,,,,,,,,,,,,,,,,0,0,65535,0,0,65535,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,””,””,””,,,””,””,,,,,,,,,,,,,,0,””,””,””,””,””,””,””,””,””,””,””,””,””,””,,,,,,,,,,,,0,0,,,0,,,,,,,,,,,,,,0,-1,-2,-2,0,””,,,,,,,,,,,,,,,,,,,,,,,,,,

 

5/ Save varexp.dat and restart the project. You will be able to retrieve directly double float values.

See in the attached sample project for an example AP_64BITS.zip

Download attachments: AP_64BITS.zip

Created on: 22 Feb 2011 Last update: 13 May 2024