Votesen VLS722 ULM device Understanding and Protocol debugged.docx

[NEAL SINGH]

 

Votesen VLS722 ULM device

Here is the key data to interface to the device

The Signal Strength and the Level and Temp are in two commands;

Get Signal Strength Command

First byte: Device ID

Second Byte: Command

Third & 4^th Byte: Register

5^th & 6th Byte: Number of registers read.

7^th & 8^th: CRC

(W HEX) [8]    01 03 01 0D 00 01 14 35

 

Response

First byte: Device ID

Second Byte: Command

Third Byte: Payload Length

Fourth & 5th Byte: Data (001E)

Sixth and 7^th: CRC

 

(R HEX) [7]    01 03 02 00 1E 38 4C

 

 

 

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Get Level &Temp Command (5 registers)

(W HEX) [8]    01 03 00 FF 00 05 B5 F9

 

First byte: Device ID

Second Byte: Command

Third & 4^th Byte: Register

5^th & 6th Byte: Number of registers read.

7^th & 8^th: CRC

 

(R HEX) [15]    01 03 0A 0D 80 FF FF 01 24 00 03 00 24 15 4C

 

Get Level &Temp Command (2 registers)

This is a better commands we don’t need the other data, just Level and Temp

(W HEX) [8]    01 03 00 FF 00 02 F4 3B

 

First byte: Device ID

Second Byte: Command

Third & 4^th Byte: Register

5^th & 6th Byte: Number of registers read.

7^th & 8^th: CRC

 

Response

(R HEX) [9]    01 03 04 0D 80 FF FF F8 C7

 

 

 

�Black core wire, sensor supply wires, connecting power supply negative pole

�Green core wire, sensor signal wires, the signal wire is marked as RX/A and connecting to the TX/A end of the user device

�Yellow core wire, sensor signal wires, the signal wire is marked as TX/B and connecting to the RX/B end of the user device

 

How to change the address of the Probe

The address change instruction is: 00 06 01 07 (**) (checksum)  “00060107B6B8”

1. (**) Please enter the address you want to change

2. (Checksum) Please replace MODBUS checksum

Alternately if you don’t know the Address, you can use a broadcast mode (1 device connected) to change the Address

(W HEX) [8]    FF 06 01 07 00 01 ED E9

(R HEX) [8]    FF 06 01 07 00 01 ED E9

 

Understanding the protocols

It is always important to know the default address of the ATG supplier. In this case it was suppose to be 01 but it turned out to be 00 – the reset of the explanation will be done with this address.

Broadcast Command to determine Address of a device

 

(W HEX) [8]    FF 03 00 FF 00 05 A0 27

(R HEX) [15]    FF 03 0A 0D 80 FF FF 01 20 00 02 00 0C E3 2D

This did two things;

1. The device was in an Auto-transmit mode (used when working with a GPS) – this command took it out of that mode.
2. It revealed the Address to be 01.

 

This is the command to specifically get the address;

(W HEX) [8]    FF 03 01 07 00 01 21 E9

(R HEX) [7]    FF 03 02 00 01 50 50

 

Command to determine the Level only for address 00

00 03 01 00 00 01 84 27 - This is the read distance value to read the liquid level height.

(W HEX) [8]    00 03 01 00 00 01 84 27

(R HEX) [7]    00 03 02 FF FF 84 34

The height is given by “FF FF”

 

Command to determine all relevant data

01 03 00 FF 00 05 B5 F9 - continue read 5 register address instructions. This is to read the sensor working time, temperature, liquid level height, version

(W HEX) [8]    01 03 00 FF 00 05 B5 F9

(R HEX) [15]    01 03 0A 0D 80 FF FF 01 20 00 02 00 0D 74 92

 

 

01 Address 03 Read function code 0A Version 0D 80 Software version FF FF Distance-  01 20 Temperature 00 02 hours 00 02 minutes 74 92 checksum