FT-13 Technical Manual, Rev. 1.40 March 2013
Page 48 of 56
Modbus exception codes
1
: Function code is not supported
2
: Address is out of range (start and end)
3
: Invalid value feed or wrong byte number
4
: Operation error
Terminal [hex] - Examples:
Performing direct read and write operations (Modbus RTU HiLo)
with the instrument address set to “01”. Empty
spaces in the example commands are only for a good pattern recognition; Use the commands without them.
Reading weight data
:
01, 03, 00,00, 00,02, C4,0B
Reading status data
:
01, 03, 00,02, 00,01, 25,CA
Reading tare data
:
01, 03, 00,03, 00,02, 34,0B
Reading last filling value
:
01, 03, 00,13, 00,02, 04, 0F,D4
Reading total weight filled
:
01, 03, 00,16, 00,02, 04, 0F,18
Reading inputs
:
01, 03, 00,18, 00,01, 02, 8D,02
Activating Tare
:
01, 10, 00,08, 00,01, 02, 00,02, 26,D9
Activating Start
:
01, 10, 00,08, 00,01, 02, 00,08, A6,DE
Activating Reset
:
01, 10, 00,08, 00,01, 02, 00,09, A3,33
Loading value 5000 to Target :
01, 10, 00,0A, 00,02, 04, 00,00,13,88, 7E,86
Loading value 50 to Tolerance :
01, 10, 00,0C, 00,02, 04, 00,00,00,32, 72,2F
Loading value 500 to Coarse
:
01, 10, 00,0E, 00,02, 04, 00,00,01,F4, 72,34
Loading value 100 to Fine
:
01, 10, 00,10, 00,02, 04, 00,00,00,64, F3,48
Activating all standard outputs :
01, 10, 00,19, 00,02, 04, 00,00,00,FF, 72,89
Activating outputs 1 and 6
:
01, 10, 00,19, 00,02, 04, 00,00,00,21, F2,D1
Loading Target, Tolerance, Coarse and Fine in one message (with above values):
01, 10, 00,0A, 00,08, 10, 00,00,13,88,00,00,00,32,00,00,01,F4,00,00,00,64, 8F,B2
-
Details of an example: Loading value “5000” to Target
01
10
00,0A
00,02
04
00,00,13,88
7E,86
FT
address
Write
function
Register
address
No. of
registers
Data byte
count
Data bytes:
Value 5000 in hex
CRC
checksum
Calculate check sums:
1. Load a 16
–bit register with FFFF hex (all 1‟s). Call this the CRC register.
2. Exclusive OR the first 8
–bit byte of the message with the low–order byte of the 16–bit CRC register, putting the result in
the CRC register.
3. Shift the CRC register one bit to the right (toward the LSB), fill a zero into the MSB. Extract and examine the LSB.
4. (If the LSB was 0): Repeat Step 3 (another shift). (If the LSB was 1): Exclusive OR the CRC register with the polynominal
value A001 hex (1010 0000 0000 0001).
5. Repeat Steps 3 and 4 until 8 shifts have been performed. When this is done, a complete 8
–bit byte will have been
processed.
6. Repeat Steps 2 through 5 for the next 8
–bit byte of the message. Continue doing this until all bytes have been
processed.
7. The final contents of the CRC register is the CRC value.
8. When the CRC is placed into the message, its upper and lower bytes must be swapped as described below.
Attention:
For hardware connection details please refer to the related hardware descriptions within this manual
For more Modbus information please refer to the web site
http://www.modbus.org
