yes.
The equipment can output:-
ASCII comma separated data with RS232, RS422 or RS485 levels.
SDI-12 format data.
Modbus ASCII or RTU data with RS232 or RS485 levels.
But now the equipment directly the computer via serial port(rs232). what should I do ? whether use modbus serial is supported? if it not support it whether I must use modbus tcp/ip?
Configuring equipment for MODBUS
equipment Supported Modbus Specification
MODBUS RTU or ASCII.
Baud Rate 9600 or 19200 Baud.
COMMS RS232 point to point only, RS485 2 wire networkable.
Modbus Parameters ASCII or RTU.
Parameter Modbus ASCII Modbus RTU
Character ASCII 0 to 9 and A to F (Hex) Binary 0 to 255
Error Check Longitudinal Redundancy Check (LRC) Cyclic Redundancy Check (CRC)
Frame Start Character ':' (3A Hex) 3.5 Characters Silence
Frame End Characters CR/LF (0D/0A Hex) 3.5 Characters Silence
Gaps in Message 1 Second 1.5 Times Character Length
Start Bit 1 1
Data Bits 7 8
Parity Even/Odd None Even/Odd None
Stop Bits 1 2 1 2
Requires:-
with version 2346-4.00 firmware and onwards.
version 2.02-02 and onwards.
Connect equipment to a PC COM port (default communication is RS232).
Open Software.
Click on Connect and Read to reach the Editing Pages as shown below.
Configuration
Click on the MODBUS Page
Mode: Choose between RTU and ASCII, in this case RTU.
Address: Choose a MetPak Address number to be between 1 to 247.
Data Bits: Choose 7 for Modbus ASCII and 8 for Modbus RTU.
Stop Bits: Choose 1 for Even/Odd Parity or 2 for No Parity (None).
Parity: Choose Even/Odd or None.
Termination Char ASCII code: Choose between 0-255.
Inter Char Timeout (ms): Choose between 500ms to 10000ms.
Operation
Select the COMMS Page
Protocol: Select MODBUS
Interface: Default is RS232. Select RS232 or RS4852W. RS232 will only
allow a single point to point non multi drop network connection. RS485 2 wire will
allow networking with up to 32 connected devices.
Baud Rate: Default is 19200. Select required Baud rate (9600 or 19200
supported).
Node ID: Default is Q. Not used for MODBUS.
Output Rate: Default is 1Hz. Set update rate for Data (0.25Hz
to 1Hz).
Message Mode: Default is CONT. Select POLL mode and equipment will
only make and output a measurement (set by the output rate) on demand from the
Modbus Master. In CONTinuous mode the MetPak continuously makes
measurements set by output rate (0.25Hz to 1Hz) and only outputs a result when
demanded from the Modbus Master.
When required settings have been selected click on Save Settings to Device
Click on Yes and OK.
Power down the and apply power back to the MetPak to complete setting
changes.
Note: now that the unit is in MODBUS mode if any further changes need to be
made use the SAFE MODE connection and method to re-establish communication
with equipment
METPAK MODBUS NOTES
- All registers are 16bit.
- The first byte is high order and the second is low.
- Each measurement is comprised of two 16bit registers.
- The registers are arranged High Word/ Low Word.
- Registers start at address 40001.
- Holding registers available in the order of the MetPak data string (which can be
established by the REPORT command in non-Modbus ASCII Mode).
MetPak Pro MODBUS Default Data String Field Encoding:
Node 4-byte character string Registers 40001-2.
Direction: 32 Bit Floating point value Registers 40003-4.
Speed: 32 Bit Floating point value Registers 40005-6.
Pressure: 32 Bit Floating point value Registers 40007-8.
Temperature: 32 Bit Floating point value Registers 40009-10.
Relative Humidity: 32 Bit Floating point value Registers 400011-12.
Dewpoint: 32 Bit Floating point value Registers 400013-14.
PRT: 32 Bit Floating point value Registers 400015-16.
AN1: 32 Bit Floating point value Registers 400017-18.
AN2: 32 Bit Floating point value Registers 400019-20.
DIG1: 32 Bit Floating point value Registers 400021-22.
Supply Voltage: 32 Bit Floating point value Registers 400023-24.
Status: 32 bit Unsigned Integer (UINT) Registers 400025-26.
See Simply Modbus program reading example MODBUS Data as
follows: