Hello,
I have a laptop (HP EliteBook 8560p) with an on-board 9-pin male com port (COM1).
I want to read RS-232 data from a digital balance using this COM1 port by using an Arduino Uno board (connected at COM8).
Digital balance is set at 9600 baud, 7-bit ASCII data, odd parity, one stop bit.
I am able to read the data using HyperTerminal but I need to read the data using Arduino IDE v1.6.9.
I looked for a simple code but not able to find any.
Which library should I use?
How do I define the COM1 port and other parameters given above?
What is the simplest code to accomplish this task?
Thanks in advance.
Muharrem Keskin
Dear Muharrem,
Unfortunately, There is no library for that. There is also no simple code for that. You must discover how to establish communication with digital balance using HyperTerminal or other programs (Serial port readers).
Arduino RS232 shield must be connected to an Arduino uno. Then, using communication protocol between balance and computer, you can read data. RS232 shield is generally connected to 0 Rx, 1 Tx pins (COM8 for you). Therefore, Serial.begin(9600) (other communication parameters is defined in device manager), serial.read and serial.write commands must be used in Arduino code.
There is no other way without using RS232 shield, as far as I know.
Good Luck,
Best Wishes,
Fatih Cemal CAN
Dear Fatih,
Thanks for your answer.
I already mentioned that I managed to read the data using HyperTerminal before.
After some trials, I managed to read the data from the balance using Arduino IDE as well.
I checked the output signal of the RS-232 cable which is -10V and +10V that is not appropriate for Arduino Uno card.
I used an RS-232 to TTL converter to convert the signal to 0-5V.
I connected TTL output to one of the PWM pin (#11) of Arduino Uno card.
I modified the sample code given on this page using CustomSoftwareSerial library:
http://forum.arduino.cc/index.php?PHPSESSID=c69ksstdemj3mfn899qnjfoku5&topic=396450.0
Best ragards,
Muharrem Keskin
Thank you for your method.
I did not use R232 TTL converter before.
This is low cost method.
Dear Muharrem Keskin .
If you want to read it through Arduino IDE then you must interface digital balance via Arduino. you must care about the voltage in it. Usually there must need some kind-off logic shifter between the arduino and balance then you can directly connect the Arduino and the Arduino IDE
Dear Muharrem
I also want connect R&D balance wit rs232-ttl to the arduino. we tested some codes but didnt give any data from balance. If it possible please share your code.
Dear Nasser,
Below are some recommendations.
Before trying to read the data using Arduino board, you should be sure that your device sends data and your PC reads it.
For this, I used a free serial terminal program on Windows 7 that I downloaded from internet. I used hyperterminal program and it had two files:
"hypertrm.dll" and "hypertrm.exe"
https://digitizor.com/install-winxp-hyperterminal-client-on-windows-vista-or-windows-7-free/
I used a PC which had built-in COM port, I connected the device and I tried different comfigurations and finally I managed seeing data on the PC screen.
In this way, I made sure that the device is sending data and the PC reads it.
Then I connected the device to RS232-to-COM-port converter and connected the converter to the Arduino board.
I copied a code from this web site and made some changes accordingly:
http://forum.arduino.cc/index.php?topic=396450.0
I used "CustomSoftwareSerial.h" library with
"CustomSoftwareSerial mySerial(11, 12)" // First Rx, Second Tx
(Mention here which Arduino pin you are using to connect the signal).
I used "mySerial.begin(9600,CSERIAL_7O1)" in the setup part of the code.
9600 baud, 7 data bits, odd parity and 1 stop bit.
(you have to make sure that your divice is configured in same way)
My device was a digital balance and it sends the mass value.
It puts a sign "+" before the mass and "g" after it.
So my code ignored any data before "+" and after "g".
If your device sends data seperated by comma, you should do parsing.
You read the data in lines and separate the data between two commas
using parsing coding.
I am also sending the code I used as attached.
I hope this helps.
If you need more help I will be glad to do so (If I can).
Muharrem Keskin
Mustafa Kemal University, Turkey
Dear Muharrem
thanks to your response and sharing your code.
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