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User's Guide

On Error Codes

On Google Play

On Raw Sensors Data

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0> Initialization

  • When starting the Modbus Monitor for the first time downloading on your device, there are no previous communications settings/preferences stored on your mobile device. Click "Reset" to default communication settings and setup new list management database.

  • The same dialog box is presented with Settings are corrupted for whatever reason or when clicking Reset Settings.

  • If you click Cancel, it will bug you again later so might as well click Reset when you know things aren't right.

1> Communications

  • Setup Basic communication settings. No reason to do anything else and then come to this step when encountered with many errors. Must specify the "IP Address" per your remote Modbus TCP device. Other Default settings are good choices that work with most devices.

  • Check that "IP Address" and "Port" matches the device you are trying to connect. Port 502 is the industry standard Modbus TCP port. Unless your device is at different port, no good reason to change it. Obviously the device you trying to connect must speak Modbus TCP protocol.

  • Station ID: Specify the default Station or Slave ID here. There is also an option to setup different Slave ID per Monitor points. Again check your Modbus server device for correct ID or you will get errors.

  • TimeOut: Specify the delay in milliseconds (ms) to wait for response before tagging the request as an error. Slow device will need higher <delay> value then faster device; obviously. If your device's manufacturer can not help you answer that question then you may want to experiment with this setting until errors are none. The default value of 3000 (ms) is a good choice.

  • Retries: The Modbus Monitor tries to resend the request on failed response. Specify the how many times should be tried again before marking the item or monitoring points as an error. The default value of 3 is usually a good choice.

  • Link Timeout: Specify how long to wait before current TCP/IP Socket is marked bad and New TCP/IP Connection Socket needs to be Reestablished. This occurs most often the the WiFi communication goes down. Default 30 seconds is good choice.

  • Inter-Packet: This settings is for advanced or lab users. This settings gives you more finer control over time to wait before sending next Modbus TCP frame. Higher value keeps smaller input buffer from overflowing and gives slower phone more time to process the information. Keep the default value if you are not getting any errors.

  • Interval: Specify how many milliseconds (ms) to wait before cycling through the whole list again. The default value of 0 updates the list as fast as possible.

  • Battery Saver: Check this box to stop updating the list of monitoring points. Uncheck the box to continue polling the data while mobile device goes to sleep state.

  • Modbus RTU: Click the check box to enable the Modbus RTU over TCP protocol.

2> Add / Change Register

  • Click here for Error Codes on this screen.

  • IP Addr:

    • Modbus Monitor (FREE): IP Address is not implemented per register or Monitoring Point. You can ignore the value or put same IP Address as in setup. See Communication section above.

    • Modbus Monitor Advanced: Enter IP Address of the TCP or TCP/RTU Client in this box with "" format.

  • "R" or "Modbus RTU over TCP" Checkbox:

    • Modbus Monitor (FREE): This feature is not implemented. Ignore this setting.

    • Modbus Monitor Advanced: Check "Modbus RTU over TCP" checkbox when client supports RTU protocol such as "RTU to TCP" converter box.

  • Name: Name your monitor point or register meaningful to you.

  • Address: Enter the address of Modbus Register in this box. The full 16-bits range of Modbus PDU can be used (0 to 65535). This is the real address that goes out inside Modbus Packet. Refer to Modbus Specification for more information. There are many addressing scheme out there that makes it very confusing for beginners. Some information to help beginners:

Modbus Classic/PLC Addresses:

Address Modbus Monitor

(4x) 40001 = Address = 1 , Function = 3, "1" Checked

(3x) 30001 = Address = 1 , Function = 4, "1" Checked

(1x) 10001 = Address = 1 , Function = 2, "1" Checked

(0x) 1 = Address = 1 , Function = 1, "1" Checked

Protocol Addresses:

Address Modbus Monitor

(4x) 40001 = Address = 0, Function = 3, "1" Not Checked

(3x) 30001 = Address = 0, Function = 4, "1" Not Checked

(1x) 10001 = Address = 0, Function = 2, "1" Not Checked

(0x) 1 = Address = 0 , Function= 1, "1" Not Checked

["1" unchecked, 0 Based]

  • "1" Checkbox: Check this box when the address in the Address box is "1" based. Thus, the range of the address becomes 1 to 65536.

  • Slave ID: Enter the ID number for the Modbus Server. The range is from 0 to 255.

  • Count: Enter the number of continuous (16-bit) register count.

  • Register Type: Pick the register type. The function code and register range is shown in the list. The following function codes are supported. Function codes: 01-Coil Status, 02-Input Status, 03-Holding Reg, 04-Input Register.

  • Data Conversion: Pick the data conversion from the list. Note that data will be shown correctly depending of several settings such as register counts, register type, and byte / word swaps.

  • Swap: Pick the correct data swap. Both byte and word swaps are supported.

  • f(x) = mx+b

    • Gain (m): Apply any gain value here after the data is processed. This is the "m" or slope part of Linear equation "f(x)=mx+b".

    • Offset (b): Apply any offset value here after the data is processed. This is the "b" or y-intercept part of the Linear equation.

    • Example: m=1.8 and b= 32 to convert from degree Celsius to degree Fahrenheit

3> Import / Export

  • Import and Export is done with common CSV format. Formats and sample file can be found below.

Import / Export Header