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F2. VPFlowScope DP/Probe/In-line register tables

Reading Time: 3 minutes - Video Time:

1. Introduction

Before you start, familiarize yourself with RS485 networks and the Modbus protocol basics.

Since RS485 networks and the Modbus protocol are typically understood only by trained technicians, we refer to chapter G9; for more information on the communication protocol, definitions and additional resources for training.

In Modbus devices, the actual measurement data is placed in holding registers. To readout this data, you will need to use the corresponding holding registers which are given in the next table. All data is stored in two 16-bit registers with below register number as a start address. Read out the data with this start address and length 2.

2. Holding register table

DecimalHEXDescriptionTypeRead / Write
160x 10Flow in mn/sec32-bit integer (x10)Read
170x 11Flow in m3/hr32-bit integer (x10)Read
180x 12Flow in ln /min32-bit integer (x10)Read
190x 13Flow in SCFM32-bit integer (x10)Read
200x 14Flow in m3n /min32-bit integer (10x)Read
210x 15Flow in sfps32-bit integer (10x)Read
320x 20Pressure in bar32-bit integer (10x)Read
330x 21Pressure in psi32-bit integer (10x)Read
640x 40Temperature in oC32-bit integer (10x)Read
650x 41Temperature in oF32-bit integer (10x)Read
1280x 80Totalizer in m3n32-bit integer (10x)Read / Write*

* Writing to the totalizer will reset the totalizer to zero.

DecimalHEXDescriptionTypeRead / Write
80x 08Diameter32-bit Floating pointRead / Write
90x 094 .. 20mA Max32-bit Floating pointRead / Write
100x 0A4 .. 20mA Min32-bit Floating pointRead / Write
110x 0B4 .. 20mA Unit32-bit Floating pointRead / Write
240x 18Flow in mn/sec32-bit Floating pointRead
250x 19Flow in m3n / hr32-bit Floating pointRead
260x 1AFlow in l/min32-bit Floating pointRead
270x 1BFlow in SCFM32-bit Floating pointRead
280x 1CFlow in m3n /min32-bit Floating pointRead
290x 1DFlow in sfps32-bit Floating pointRead
400x 28Pressure in bar32-bit Floating pointRead
410x 29Pressure in psi32-bit Floating pointRead
720x 48Temperature in oC32-bit Floating pointRead
730x 49Temperature in oF32-bit Floating pointRead
1360x 88Totalizer in m3n32-bit Floating pointRead / Write*

* Writing to the totalizer will reset the totalizer to zero.

Available write operations

You can also configure some parameters of the VPFlowScope DP / Probe and In-line via Modbus.

3. Modbus settings

The Modbus settings can be changed via the display and with VPStudio 2 you can change the options below:

  • Hardware address: 1-247
  • Integer multiplier: 1-1000

When the type of your Modbus is integer your output is rounded to the nearest integers. This will sometimes result in a less precise outcome. To get your output more precise VPStudio 2 has an integer multiplier option. With this option, you can multiply the outcome to get a more significant output.

The output of your temperature in Modbus is 33 degrees. You set your integer multiplier to 100.

The new output of your temperature is 3343. So actually the temperature is 33.4 degrees.

In chapter B6 we show how to change your Modbus settings.

Data format
Function code 0x03 for reading(Holding register).
Function code 0x10 for writing (Holding register).
32-bit Floating point Little-endian [CDAB]
32-bit signed Integer Little-endian [CDAB]

4. Next step

There are many ways to readout your VPFlowScope. Go to the next chapter to learn more about the real-time readout via VPStudio 2 software. The key for a long lifetime and reliable measurement results, it is key to service the equipment on a regular basis.

Next step:

Updated on July 8, 2020

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