Aug 27, 2013 Solution 1. Accept Solution Reject Solution. How about just doing what the name suggests: add up the individual bytes (disregarding overflow), and append the resulting value at the end of the package. Do the same on the receiving end and verify that the last value correspnds to the sum of the rest. Browse other questions tagged c string serial-port checksum or ask your own question. The Overflow Blog Podcast 377: You don't need a math PhD to play Dwarf Fortress, just to code it. Checksum, the algo i would like to use is. Init a counter to 0, read 1 byte data using NI VISA read, change the increment the counter to 1. Read next byte using VISA read, this shud be the checksum sent my micro-controller, if checksum is correct, send an ACK to uC, remove the checksum byte, save only the data byte.
Hi all, i am trying to use my arduino as a modbus master to send 1 bit of data through RTU.
Checksum Error Serial Port Number
When press my digital input from arduino master, modbus poll & modbus tester throw up errors and i cannot receive the data correctly. I have been trying to debug this for many days now and have been unsuccessful, i have re wired my project and checked my code but still cannot figure out these errors.
On Modbuspoll i get ' checksum error' and when no inputs pressed 'timeout error', i have included my wiring and code below along with pictures of the errors that i am receiving.
Element 3d plugin after effects free mac. I also get read rs port error & or illegal response when using mbustester
Checksum Error Serial Port List
I am trying to send the data through the address 0x10001 in order for my slave to read the input of 1 which is sent from the digital input on the arduino.
Hardware:
Arduino Uno
5V TTL to Rs485 Module
SH-U10 USB to RS485 Converter
Push Button
LCD
Hardware:
Arduino Uno
5V TTL to Rs485 Module
SH-U10 USB to RS485 Converter
Push Button
LCD
Code:
I also receive an error whilst compiling although i am able to upload this to the device and other functions work ie, lcd print functioning correct when press digital input
When running 'rosrun rosserial_python serial_node.py /dev/ttyACM0' I get the error message 'wrong checksum for topic id and msg'. After that it may continue to connect but the error 'Serial Port read returned short (expected 78 bytes, received 5 instead).' comes up, or it may just not connect and keep trying. Whats weirder is if I restart the PC and run the code it works fine, I can launch RVIZ, with 'roslaunch robot_description robot_description.py' and it will show me the range sensor and move about as i move my hand to and from the sensor. The next time I run it I get the above errors.
The code I am using is below. pretty basic for the tf stuff, really just copied the arduino copy as a test