Modbus Easyview

What is Modbus?
Modbus is a protocol used by many measuring devices to make current readings available to other systems. Devices that support Modbus have a register table containing current readings, among other things. A so-called "master" can connect to one or more measuring devices (called "slaves") and read current values from specific registers. Often, a master is a type of hardware like a PLC, but software like EasyView can also act as a master.

Getting Started
If you’re connected to your device via USB cable or a USB to RS485 adapter, select “RTU” at the top. If connected via network, select “TCP.”

To log via Modbus TCP, you need to know your device’s IP address and the port to use. If the device has a display, the IP address and port may be shown there. Otherwise, you can find the IP address by logging into the network’s router. The default port for Modbus TCP is 502.

To log via Modbus RTU, you’ll need the COM port, baud rate, parity, stop bits, and data bits. You can identify the COM port by checking which one appears in the Windows Device Manager when the USB cable is connected. Other settings are usually in the manual or selected in the device's configuration software. If connected to a Flexible Head Unit via the USB port on the front, baud rate, parity, stop bits, and data bits don’t matter.

When the communication settings are correct, click “New Register” at the bottom to add a new register. A new row should appear in the table, where you can specify slave address, register, number of decimals, function code, data type, label, unit, and range.

If the devices you want to communicate with have a display, the slave address is often shown there. Otherwise, you may need to use the device’s configuration software to find and change the slave address. Make sure no devices have the same slave address. If connected to a Flexible Head Unit via Ethernet or USB on the front, the default slave address is 255.

The registers, number of decimals, function code, and data type are usually specified in the device’s manual. Note that some manufacturers start counting from register 1, while others start from register 0. EasyView starts counting from register 0, so if you encounter issues, try the previous register. Also, some manufacturers combine registers and function codes. For example, if the manual states register 30001, it usually means you should enter register 0 and function code 04 in EasyView. If it says 40001, use register 0 and function code 03.

If the manual for your device states Int16*10 in the register table, it means the value sent by the device is 10 times larger, requiring the decimal point to be shifted one place for correct presentation. In this case, set 1 as the number of decimals. If using a Flexible Head Unit, the number of decimals per channel is chosen in the configuration software. For correct presentation in EasyView, the same number of decimals must be set.

Once the configuration is complete and you want to check that everything works, click "Read Measurements...". EasyView will then read current values and display them under “Measured Value” for each register. Before starting the measurement, it’s a good idea to save your settings. Do this by clicking “Save Template…” at the top. All configurations are stored in a file, which can easily be reloaded by clicking “Open Template…”.

Example
Below is an example of a configuration for an Intab Flexible Head Unit. In this case, the head unit is connected to the network and has 5 PT100 sensors connected on channels 1-5. Each channel is set to store 2 decimals.

Troubleshooting
If “Measured Value” turns red and says “Failed,” it means either EasyView didn’t receive a response, the response took too long, or an incorrect register was requested. If this happens, you can start by checking “Log Commands” and selecting where to save the log file. Then click “Read Measurements…” and open the log file. Each line in the log has a timestamp followed by either > or <. Lines with > indicate what EasyView sent, and lines with < are responses. If no response appears, the communication settings are likely incorrect.

If you’re trying to retrieve data via Modbus RTU:

• Check that the communication settings are correct.
• Verify that the slave address and function code are correct.
• Increase “Time Between Messages” and try again.

If you’re trying to retrieve data via Modbus TCP:

• Ensure the IP address and port are correct.
• Verify that the slave address and function code are correct.
• Open the command prompt, ping the IP address, and check if the device responds.
• Make sure communication on the specified port is allowed in the firewall.

If there’s a response in the log file but it still says “Failed,” it may mean an incorrect register has been specified.

OPC in Easyview

We have implemented OPC UA in Easyview 

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