Sonic Driver Ultrasonic Flow Transmitter Modbus RTU Slave Meter Instruction Manual
Introduction
Modbus RTU Slave functionality is implemented on the Sonic Driver TM clampon Ultrasonic Flow Transmitter(UFT).
Meter settings are fully configurable on the UFT using a Windows based program running on a PC or laptop. In addition a full range of flow measurements and diagnostics can be read from the meter.
Once installed and commissioned the computer can be disconnected and the meter wired back to a control room PCL or similar.
Mode
The Modbus RTU protocol is implemented over RS485 hardware.
Mobile connection uses a USB-RS45 converter cable.
Baud rate
The RS485 baud rate is 19200.
Parity
The RS485 parity is Even.
Stop Bits
The RS485 stop bits is 1.
Modbus Address
The UFT Slave address is programmable from 1 to 255.
The default Slave address is set to 1.
Data bits
RS485 serial data is fixed at 8 bits.
Register format
In the UFT each Modbus register is a 16-bit word, consisting of two 8-bit bytes.
Register data in Modbus messages are packed as 2 bytes per register. The binary contents are right justified in each byte. For each register the first byte contains the high order bits and the second byte contains the low order bits.
A floating-point number is stored as 32 bits using 4 bytes and therefore occupies 2 Modbus registers.
Representation of floating-point values
The UFT stores floating point values in IEEE 754 single precision format.
The bus Master accesses a floating-point value from any one of 4 different register tables. Each register table represents a different byte order.
| Table start | Byte order | Common Description |
| 0x0000 | 1,0,3,2 | Floating-point Little-Endian with byte swap (Default) |
| 0x1000 | 0,1,2,3 | Floating-point Little-Endian Format |
| 0x2000 | 3,2,1,0 | Floating-point Big-Endian Forma |
| 0x3000 | 2,3,0,1 | Floating point Big-Endian with byte swap |
By reading the first 2 registers of each table the user can determine which format matches their system when a fixed test value of 1234.0 is received.
Modbus Commands
The UFT implements Modbus commands 03, 04, 06 and 16.
Read Holding Registers 03
This function code is used to read from 2 to 110 contiguous holding registers from the UFT. Registers are addressed starting at zero. Therefore holding registers numbered 1-110 are addressed as 0-109.
The Modbus Master specifies a start address and register count.
Read Input Registers 04
This function code is used to read from 2 to 110 contiguous input registers from the flowmeter. Registers are addressed starting at zero. Therefore input registers numbered 1-110 are addressed as 0-109.
The Modbus Master specifies a start address and register count.
Write Single Register 06
This function code is used to write a single register. This function code is used to program integer values in the UFT.
The Master specifies an address and 16-bit data value for write.
The value is an unsigned 16-bit value. Valid values are defined for each register address, see appendix 3
Writing a value of 0x00 to register 60011 will clear the unit’s internal error log.
Write Single Register 16
This function code is used to write multiple registers. This function code is used to program 32-bit floating-point values in the UFT.
The Master specifies an address and 32-bit data value for write
The value is a pair of unsigned 16-bit values. Valid values are defined for each register address, see appendix 3.
Broadcast address
The UFT supports broadcast address 0.
In broadcast address mode the Modbus master can send a command to all slaves.
No response is sent by the slaves.
Communications Software
There are several communications programs available for download online.
The UFT has been tested using Modbus Poll (for Windows platform) and Modbus Monitor (for Android and Windows platforms).
Appendix 1: Communication Command Structure
| Read holding registers | ||
| Slave ID | (1 byte) | |
| Function | (1 byte=03H) | |
| Start Address | (2 bytes) | |
| No. of Registers R | (2 bytes) | |
| CRC code | (2 bytes) | |
| Reply | ||
| Slave ID | (1 byte) | |
| Function | (1 byte) | |
| N = 2R | Byte Count N | (1 byte) |
| Hex Data | (N bytes) | |
| CRC code | (2 bytes) | |
| Read input registers | ||
| Slave ID | (1 byte) | |
| Function | (1 byte=04H) | |
| Start Address | (2 bytes) | |
| No. of Registers R | (2 bytes) | |
| CRC code | (2 bytes) | |
| Reply | ||
| Slave ID | (1 byte) | |
| Function | (1 byte) | |
| N = 2R | Byte Count N | (1 byte) |
| Hex Data | (N bytes) | |
| CRC code | (2 bytes) | |
| Write single register | Slave ID | (1 byte) |
| Function | (1 byte=06H) | |
| Start Address | (2 bytes) | |
| Hex Data | (2 bytes) | |
| CRC code | (2 bytes) | |
| Write multiple registers | Slave ID | (1 byte) |
| Function | (1 byte=10H) | |
| Start Address | (2 bytes) | |
| No. of Registers R | (2 bytes) | |
| N = 2R | Hex Data | (N bytes) |
| CRC Code | (2 bytes) | |
Appendix 2: Command 03 and 04 UFT Register Map
| Modbus Address | Measurement/Variable | Bytes | Format |
| 40001 | Fixed test pattern 1234.0 | 4 | IEEE |
| 40002 | |||
| 40003 | Flow Velocity (m/s) | 4 | IEEE |
| 40004 | |||
| 40005 | Flow Rate Volumetric (l/min) | 4 | IEEE |
| 40006 | |||
| 40007 | Flow Rate Mass (kg/min) | 4 | IEEE |
| 40008 | |||
| 40009 | NA | 4 | IEEE |
| 40010 | |||
| 40011 | Amplifier gain (dB) | 4 | IEEE |
| 40012 | |||
| 40013 | Signal Amplitude (dB) | 4 | IEEE |
| 40014 | |||
| 40015 | Signal Noise (dB) | 4 | IEEE |
| 40016 | |||
| 40017 | SNR (dB) | 4 | IEEE |
| 40018 | |||
| 40019 | Delta Time Difference (ns) | 4 | IEEE |
| 40020 | |||
| 40021 | Upstream Transit Time (us) | 4 | IEEE |
| 40022 | |||
| 40023 | Downstream Transit Time (us) | 4 | IEEE |
| 40024 | |||
| 40025 | Arrival Bin | 4 | IEEE |
| 40026 | |||
| 40027 | Signal Quality 1 (us) | 4 | IEEE |
| 40028 | |||
| 40029 | Signal Quality 2 (ADU) | 4 | IEEE |
| 40030 | |||
| 40031 | Meter Error Code | 4 | IEEE |
| 40032 | |||
| 40033 | Transducer Type (List) | 4 | IEEE |
| 40034 | |||
| 40035 | Transducer Wedge Angle (deg) | 4 | IEEE |
| 40036 | |||
| 40037 | Transducer SOS at 20 deg C (m/s) | 4 | IEEE |
| 40038 | |||
| 40039 | Transducer SOS at 60 deg C (m/s) | 4 | IEEE |
| 40040 | |||
| 40041 | Transducer Crystal Offset (m) | 4 | IEEE |
| 40042 | |||
| 40043 | Transducer Spacing Offset (m) | 4 | IEEE |
| 40044 | |||
| 40045 | Transducer Frequency Code (List) | 4 | IEEE |
| 40046 | |||
| 40047 | Transducer Delta Time Offset(ns) | 4 | IEEE |
| 40048 | |||
| 40049 | Transducer K Factor | 4 | IEEE |
| 40050 | |||
| 40051 | Pipe Type (List) | 4 | IEEE |
| 40052 | |||
| 40053 | Pipe SOS (m/s) | 4 | IEEE |
| 40054 | |||
| 40055 | Pipe Outer Diameter (m) | 4 | IEEE |
| 40056 | |||
| 40057 | Pipe Wall Thickness (m) | 4 | IEEE |
| 40058 | |||
| 40059 | Pipe Inner Wall Roughness (m) | 4 | IEEE |
| 40060 | |||
| 40061 | Fluid Type (List) | 4 | IEEE |
| 40062 | |||
| 40063 | Fluid Temperature (deg C) | 4 | IEEE |
| 40064 | |||
| 40065 | Fluid SOS (m/s) | 4 | IEEE |
| 40066 | |||
| 40067 | Fluid Density (kg/m3) | 4 | IEEE |
| 40068 | |||
| 40069 | Fluid Kinematic (cSt) | 4 | IEEE |
| 40070 | |||
| 40071 | Fluid SHC (J/(kg.K)) | 4 | IEEE |
| 40072 | |||
| 40073 | Flow Minimum Cut-off (m/s) | 4 | IEEE |
| 40074 | |||
| 40075 | Flow Damping (s) | 4 | IEEE |
| 40076 | |||
| 40077 | Modbus Address | 4 | IEEE |
| 40078 | |||
| 40079 | Corrected SOS (m/s) | 4 | IEEE |
| 40080 | |||
| 40081 | Window Delay (us) | 4 | IEEE |
| 40082 | |||
| 40083 | Zero Tracking (On/Off) | 4 | IEEE |
| 40084 | |||
| 40085 | Zero Calibration (On/Off) | 4 | IEEE |
| 40086 | |||
| 40087 | NA | 4 | IEEE |
| 40088 | |||
| 40089 | NA | 4 | IEEE |
| 40090 | |||
| 40091 | NA | 4 | IEEE |
| 40092 | |||
| 40093 | Flow Profile K Factor | 4 | IEEE |
| 40094 | |||
| 40095 | Reynolds Number | 4 | IEEE |
| 40096 | |||
| 40097 | Number of Passes | 4 | IEEE |
| 40098 | |||
| 40099 | Tup Method | 4 | IEEE |
| 40100 | |||
| 40101 | Transducer Spacing (m) | 4 | IEEE |
| 40102 | |||
| 40103 | ATA/ETA (%) | 4 | IEEE |
| 40104 | |||
| 40105 | NA | 4 | IEEE |
| 40106 | |||
| 40107 | NA | 4 | IEEE |
| 40108 | |||
| 40109 | NA | 4 | IEEE |
| 40110 | |||
| 40111 | Interval On/Off | 4 | IEEE |
| 40112 | |||
| 40113 | NA | 4 | IEEE |
| 40114 | |||
| 40115 | NA | 4 | IEEE |
| 40116 | |||
| 40117 | NA | 4 | IEEE |
| 40118 | |||
| 40119 | Positive Volumetric Total (l) | 4 | IEEE |
| 40120 | |||
| 40121 | Negative Volumetric Total (l) | 4 | IEEE |
| 40122 | |||
| 40123 | Net Volumetric Total (l) | 4 | IEEE |
| 40124 |
Text Strings, company name (26 chars), model code (26 chars), serial number (8 chars), HW/SW version (6 chars)
| Modbus Address | Text Strings, 2 chars | Bytes | Format |
| 40300 | So | 2 | Word |
| 40301 | ni | 2 | Word |
| 40302 | c< > | 2 | Word |
| 40303 | Dr | 2 | Word |
| 40304 | Iv | 2 | Word |
| 40305 | er | 2 | Word |
| 40306 | < >< > | 2 | Word |
| 40307 | < >< > | 2 | Word |
| 40308 | < >< > | 2 | Word |
| 40309 | < >< > | 2 | Word |
| 40310 | < >< > | 2 | Word |
| 40311 | < >< > | 2 | Word |
| 40312 | < >< > | 2 | Word |
| 40313 | UF | 2 | Word |
| 40314 | T<> | 2 | Word |
| 40315 | <><> | 2 | Word |
| 40316 | <><> | 2 | Word |
| 40317 | <><> | 2 | Word |
| 40318 | <><> | 2 | Word |
| 40319 | <><> | 2 | Word |
| 40320 | <><> | 2 | Word |
| 40321 | <><> | 2 | Word |
| 40322 | <><> | 2 | Word |
| 40323 | < >< > | 2 | Word |
| 40324 | < >< > | 2 | Word |
| 40325 | < >< > | 2 | Word |
| 40326 | 30 | 2 | Word |
| 40327 | 00 | 2 | Word |
| 40328 | 00 | 2 | Word |
| 40329 | 00 | 2 | Word |
| 40330 | 10 | 2 | Word |
| 40331 | 01 | 2 | Word |
| 40332 | 00 | 2 | Word |
Serial number in the example is 3000000, HW and SW versions are 1.00 and 1.00.
Signal Data Trace Values, as pairs of 8-bit values.
| Modbus Address | Signal Data Trace Value Pairs | Bytes | Format |
| 40401 | 8-bit data point 0, 8-bit data point 1 | 2 | WORD |
| 40402 | 8-bit data point 2, 8-bit data point 3 | 2 | WORD |
| 40403 | 8-bit data point 4, 8-bit data point 5 | 2 | WORD |
| 40404 | 8-bit data point 6, 8-bit data point 7 | 2 | WORD |
| 40405 | 8-bit data point 8, 8-bit data point 9 | 2 | WORD |
| 40406 | 8-bit data point 10, 8-bit data point 11 | 2 | WORD |
| .. | …,… | .. | … |
| .. | …,… | .. | … |
| 40649 | 8-bit data point 496, 8-bit data point 497 | 2 | WORD |
| 40650 | 8-bit data point 498, 8-bit data point 499 | 2 | WORD |
Appendix 3: Command 06 and 16 Definitions
| Write Single | Write Multiple | 16/32 bit Write | Value | Default | Minimum | Maximum | SI Unit | ||||||||||||
| Value | CMD 06 | CMD 16 | |||||||||||||||||
| Transducer Type | 0 | 16 | 1 | 1 | 0 | 3 | List | DN40/DM10/DM20/DS10 | |||||||||||
| Transducer Wedge Angle | 0 | 32 | 40.000 | 40.000 | 1.000 | 90.000 | deg | ||||||||||||
| Transducer SOS at 20degC | 2 | 32 | 2522.000 | 2522.000 | 500.000 | 7000.000 | m/s | ||||||||||||
| Transducer SOS at 60degC | 4 | 32 | 2522.000 | 2522.000 | 500.000 | 7000.000 | m/s | ||||||||||||
| Transducer Crystal Offset | 6 | 32 | 0.012 | 0.012 | 0.001 | 0.100 | m | ||||||||||||
| Transducer Spacing Offset | 8 | 32 | 0.030 | 0.030 | 0.001 | 0.100 | m | ||||||||||||
| Transducer Transmit Code | 1 | 16 | 1 | 1 | 0 | 2 | 4/1/2 MHz | ||||||||||||
| Transducer Delta Transit Time Offset | 10 | 32 | 0 | 0 | -2.00E-08 | 2.00E-08 | s | ||||||||||||
| Transducer K Factor | 12 | 32 | 1.000 | 1.000 | 0.001 | 1000.000 | |||||||||||||
| Pipe Type | 2 | 16 | 0 | 0 | 0 | 6 | List | Carbon Steel/Stainless Steel/Copper/PVC/Cast Iron/Ductile Iron/HDPE | |||||||||||
| Pipe SOS | 14 | 32 | 3230.0 | 3230.0 | 500.0 | 7000.0 | m/s | ||||||||||||
| Pipe Outer Diameter | 16 | 32 | 0.0606 | 0.0606 | 0.01 | 6.50 | m | ||||||||||||
| Pipe Wall Thickness | 18 | 32 | 0.0032 | 0.0032 | 0.0005 | 0.1 | m | ||||||||||||
| Pipe Inner Wall Roughness | 20 | 32 | 0.00001 | 0.00001 | 0.000001 | 0.002 | m | ||||||||||||
| Fluid Type | 3 | 16 | 0 | 0 | 0 | 3 | List | Water/Petrol/Diesel/Glycol-Water | |||||||||||
| Fluid Temperature | 22 | 32 | 18.000 | 18.000 | 0.000 | 150.000 | deg C | ||||||||||||
| Fluid SOS | 24 | 32 | 1475.000 | 1475.000 | 50.000 | 3000.000 | m/s | ||||||||||||
| Fluid Density | 26 | 32 | 998.520 | 998.520 | 50.000 | 3000.000 | kg/m2 | ||||||||||||
| Fluid Kinematic | 28 | 32 | 1.080 | 1.080 | 0.001 | 40000.000 | cSt | ||||||||||||
| Fluid Specific Heat Capacity | 30 | 32 | 4184.000 | 4184.000 | 10.000 | 10000.000 | J/(g.K) | ||||||||||||
| Minimum Flow Cut Off | 32 | 32 | 0.025 | 0.025 | 0.000 | 1.000 | m/s | ||||||||||||
| Flow damping | 4 | 16 | 10 | 10 | 0 | 255 | s | ||||||||||||
| Modbus Address | 5 | 16 | 1 | 1 | 1 | 255 | |||||||||||||
| Transducer Wedge Corrected SOS | 34 | 32 | 2522.000 | 2522.000 | 500.000 | 7000.000 | m/s | ||||||||||||
| Sampling Window delay | 6 | 16 | 169 | 169 | 11 | 65535 | us | ||||||||||||
| Zero Tracking On/Off | 7 | 16 | 1 | 1 | 0 | 1 | On/Off | ||||||||||||
| Zero calibration On/Off | 8 | 16 | 0 | 0 | 0 | 1 | On/Off | ||||||||||||
| Number of Passes | 10 | 16 | 4 | 4 | 1 | 16 | |||||||||||||
| Tup Method | 12 | 16 | 3 | 3 | 0 | 4 | List | Method 0, 1, 2, 3, 4 | |||||||||||
| Interval On/Off | 13 | 16 | 0 | 0 | 0 | 5 | On/Off | 0 – Off, 5 – On | |||||||||||
Documents / Resources
 |
Sonic Driver Ultrasonic Flow Transmitter Modbus RTU Slave Meter [pdf] Instruction Manual Ultrasonic Flow Transmitter Modbus RTU Slave Meter, Ultrasonic, Flow Transmitter Modbus RTU Slave Meter, Transmitter Modbus RTU Slave Meter, Modbus RTU Slave Meter, RTU Slave Meter, Slave Meter |
