PT113
Instruction Manual
40
Zero Calibration
01,10,00,08,00,01,02,00,01,66,D8
Weight Mode Selection
01,10,00,0D,00,01,02,00,04,A6,8E
5 mV Input signal range selection
01,10,00,0E,00,01,02,00,00,A7,7E
Load Medium (5) to Digital filter
01,10,00,0F,00,01,02,00,05,66,AC
Span Calibration Command with Span value 50000
01,10,00,09,00,03,06,00,DC,00,00,C3,50,B7,B0
Read Voltage of Power Supply value
01,03,00,21,00,01,D4,00
Answer of Voltage of Power Supply
(Voltage of Power Supply is 23.5 V)
01,03,02,00,EB,F8,0B
The above commands are not the complete Modbus transmissions, they do not include the header.
A typical complete transmission without checksum, <CR> or <LF> is shown below.
The command is 000100000006110300210001 where each pair of digits is hexadecimal for a
character.
00 01 00 00 00 06 11 03 00 21 00 01
00 01 is the transaction identifier,
00 00 is the protocol identifier,
00 06 is the message length (i.e. 6 bytes to follow)
11 is the unit identifier (address). Hex 11 = decimal 17. Preset to 01 for RS-232C and Ethernet.
03
is the function code (read analogue registers)
00 21 is the address of the first register requested, hex 0021 = dec. 33. Address = 40001+33=40034
(for the PT113 this is power supply voltage)
00 01 is the total number of registers to read.
A typical response shown here in hexadecimal is 0001000000051103020077
Transaction 0001, protocol 0000, length 0005, address 11, function 03, data bytes 02, data 0077.
Hex 0077 = dec. 119 = voltage 11.9
Note: Weight values are transmitted as an integer without decimal point and 2s compliment for negative
values.
9.1.2.2 CHK Checksum
For RS-232C and RS-485 calculate the checksum without the header, from the address (unit identifier)
onwards. The checksum is a CRC-16 Modbus checksum comprising 2 bytes with the low order byte
inserted first. Consult the Modbus website or use an online CRC generator such as
http://www.tahapaksu.com/crc/.
9.1.2.3 Command Termination
Transmit commands with a <CR><LF> termination on RS232C and RS-485 and without the termination
over Ethernet.