What products are involved?
Rheonics SRV viscometer, SRD density-viscosity meter, DVP gas density-viscosity meter and DVM HPHT density-viscosity meter.
What is the purpose of this article?
This article describes the procedure for reading Modbus Input Register from Rheonics Viscosity and Density sensors using ModScan
1. Overview
ModScan is a Windows application that operates as a Modbus master. It is ideal for quick and easy testing of Rheonics Modbus TCP protocol by validating communication parameters, such as register types and data formats, before full integration into the process or for troubleshooting purposes. ModScan can be downloaded from WinTECH’s website.
This article will provide step-by-step instructions on how to use ModScan to successfully read Modbus TCP Input Registers from Rheonics viscosity and density sensors.
2. Intro to ModScan
The first step is to connect to Rheonics Sensor via TCP/IP from the PC. Usually this is done by connecting an Ethernet Cable to the Rheonics SME Ethernet port.
On the PC, open ModScan64 software and click on Connection menu, then on Connect.
Figure 1. ModScan Software
Connection Details configuration will show up. Fill the options as shown on Figure 2 and click OK.
Figure 2. ModScan Connection Details
Next, select the Input Registers of interest. Modbus TCP - Input Registers: Rheonics Support shows a complete list of Input Registers available for Rheonics Viscosity and Density sensors. The most used are listed on Table 1.
Table 1. Most used Input Registers - Float32
Parameter Name | Address (Dec) | Register (Dec) | Length (Reg) | Type | Description |
Temperature Median | 56 | 300057 | 2 | Float32 | Parameter 2 value as float |
Viscosity Last Good | 136 | 300137 | 2 | Float32 | Parameter 12 value as float |
Density Last Good | 144 | 300145 | 2 | Float32 | Parameter 13 value as float |
In this example, a single Modbus request with the maximum allowable length (125) is used to view the majority of the records at once. However, the length can be adjusted to include only the specific records required for the user’s application.
Fill the options as shown on Figure 3.
Figure 3. ModScan Input Register Settings
Rheonics Input Registers come in two formats: Float32 and SInt16 as detailed in Modbus TCP - Input Registers. To read Float32 Registers, select Float (MSRF), as shown on Figure 4.
Figure 4. ModScan - Float (MSRF)
Figure 5 shows the Input Registers for a Rheonics Viscosity Sensor. The parameters from Table 1 are highlighted in red.
Figure 5. ModScan - Float32 Input Registers
3. References
- Rheonics Support, "Modbus TCP - Input Registers," Feb. 29, 2024. [Online]. Available: Modbus Input Registers. [Accessed: Jan. 6, 2025].
- Rheonics Support, "Using Modbuspoll pre-configured files for Rheonics Modbus Devices," Rheonics Support Portal, Feb. 29, 2024. [Online]. Available: Using Modbuspoll pre-configured files for Rheonics Modbus Devices. [Accessed: Jan. 6, 2025].