Python Pyserial Readline Example

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Usage examples can be found in the examples where two TCP/IP - serial converters are shown, one using threads (the single port server) and an other using select (the multi port server). Note Each new client connection must create a new instance as this object (and the RFC 2217 protocol) has internal state. Python documentation: Read from serial port. Initialize serial device. Data = ser.readline to read the data from serial device while something is.

Miniterm¶

Miniterm is now available as module instead of example.see serial.tools.miniterm for details.

Python File Readlines

miniterm.py
The miniterm program.
setup-miniterm-py2exe.py
This is a py2exe setup script for Windows. It can be used to create astandalone miniterm.exe.

TCP/IP - serial bridge¶

This program opens a TCP/IP port. When a connection is made to that port (e.g.with telnet) it forwards all data to the serial port and vice versa.

This example only exports a raw socket connection. The next examplebelow gives the client much more control over the remote serial port.

  • The serial port settings are set on the command line when starting theprogram.
  • There is no possibility to change settings from remote.
  • All data is passed through as-is.
tcp_serial_redirect.py
Main program.

Single-port TCP/IP - serial bridge (RFC 2217)¶

Simple cross platform RFC 2217 serial port server. It uses threads and isportable (runs on POSIX, Windows, etc).

  • The port settings and control lines (RTS/DTR) can be changed at any timeusing RFC 2217 requests. The status lines (DSR/CTS/RI/CD) are polled everysecond and notifications are sent to the client.
  • Telnet character IAC (0xff) needs to be doubled in data stream. IAC followedby another value is interpreted as Telnet command sequence.
  • Telnet negotiation commands are sent when connecting to the server.
  • RTS/DTR are activated on client connect and deactivated on disconnect.
  • Default port settings are set again when client disconnects.

New in version 2.5.

rfc2217_server.py
Main program.
setup-rfc2217_server-py2exe.py
This is a py2exe setup script for Windows. It can be used to create astandalone rfc2217_server.exe.

Multi-port TCP/IP - serial bridge (RFC 2217)¶

This example implements a TCP/IP to serial port service that works withmultiple ports at once. It uses select, no threads, for the serial ports andthe network sockets and therefore runs on POSIX systems only.

  • Full control over the serial port with RFC 2217.
  • Check existence of /tty/USB0...8. This is done every 5 seconds usingos.path.exists.
  • Send zeroconf announcements when port appears or disappears (usespython-avahi and dbus). Service name: _serial_port._tcp.
  • Each serial port becomes available as one TCP/IP server. e.g./dev/ttyUSB0 is reachable at <host>:7000.
  • Single process for all ports and sockets (not per port).
  • The script can be started as daemon.
  • Logging to stdout or when run as daemon to syslog.
  • Default port settings are set again when client disconnects.
  • modem status lines (CTS/DSR/RI/CD) are not polled periodically and the servertherefore does not send NOTIFY_MODEMSTATE on its own. However it responds torequest from the client (i.e. use the poll_modem option in the URL whenusing a pySerial client.)

Requirements:

  • Python (>= 2.4)
  • python-avahi
  • python-dbus
  • python-serial (>= 2.5)

Installation as daemon:

  • Copy the script port_publisher.py to /usr/local/bin.
  • Copy the script port_publisher.sh to /etc/init.d.
  • Add links to the runlevels using update-rc.dport_publisher.shdefaults99
  • That’s it :-) the service will be started on next reboot. Alternatively runinvoke-rc.dport_publisher.shstart as root.

New in version 2.5: new example

port_publisher.py
Multi-port TCP/IP-serial converter (RFC 2217) for POSIX environments.
port_publisher.sh
Example init.d script.

Python Pyserial Read Example

wxPython examples¶

A simple terminal application for wxPython and a flexible serial portconfiguration dialog are shown here.

Python pyserial readline example python
wxTerminal.py
A simple terminal application. Note that the length of the buffer islimited by wx and it may suddenly stop displaying new input.
wxTerminal.wxg
A wxGlade design file for the terminal application.
wxSerialConfigDialog.py
A flexible serial port configuration dialog.
wxSerialConfigDialog.wxg
The wxGlade design file for the configuration dialog.
setup-wxTerminal-py2exe.py
A py2exe setup script to package the terminal application.

Unit tests¶

The project uses a number of unit test to verify the functionality. They allneed a loop back connector. The scripts itself contain more information. Alltest scripts are contained in the directory test.

The unit tests are performed on port loop:// unless a different devicename or URL is given on the command line (sys.argv[1]). e.g. to run thetest on an attached USB-serial converter hwgrep://USB could be used orthe actual name such as /dev/ttyUSB0 or COM1 (depending on platform).

run_all_tests.py
Collect all tests from all test* files and run them. By default, theloop:// device is used.
test.py
Basic tests (binary capabilities, timeout, control lines).
test_advanced.py
Test more advanced features (properties).
test_high_load.py
Tests involving sending a lot of data.
test_readline.py
Tests involving readline.
test_iolib.py
Tests involving the io library. Only available for Python 2.6 andnewer.
test_url.py
Tests involving the URL feature.

Download the Serial Example: DSIPythonEX (zipped .py)

After python and the pyserial module has been installed on your system, this example code will send connect, send, and receive commands from our products:

# for PYTHON 3+ with pySerial module installed# DS INSTRUMENTS 2017 PYTHON SCPI REMOTE CONTROL EXAMPLE

import serial # use the serial module (https://pypi.python.org/pypi/pyserial)

import time # delay functions

badCommandResponse = b'[BADCOMMAND]rn’ # response if a command failed (b makes it into bytes)

ser = serial.Serial(“COM79”, 115200, timeout=1) #Change the COM PORT NUMBER to match your device

if ser.isOpen(): # make sure port is open

print(ser.name + ‘ open…’) # tell the user we are starting

ser.write(b’*IDN?n’) # send the standard SCPI identify command

myResponse = ser.readline() # read the response

print(b’Device Info: ‘ + myResponse) # print the unit information

Python pyserial readline examples

time.sleep(0.1) # delay 100ms

ser.write(b’PHASE?n’) # try asking for phase

myResponse = ser.readline() # gather the response

if myResponse != badCommandResponse: #is this is not a phase shifter why print the error

print(b’Phase=’ +myResponse)

time.sleep(0.1) # delay 100ms

ser.write(b’FREQ:CW?n’) # try asking for signal generator setting

myResponse = ser.readline() # gather the response

if myResponse != badCommandResponse: # is this is not a signal generator why print the error

print(b’Frequency=’ + myResponse)

time.sleep(0.1) # delay 100ms

Example

ser.write(b’ATT?n’) # try asking for step attenuator setting

myResponse = ser.readline() # gather the response

if myResponse != badCommandResponse: # is this is not an attenuator why print the error

print(b’Attenuation=’ + myResponse)

time.sleep(0.1) # delay 100ms

ser.write(b’FREQ:CW 3GHZn’) #lets change a setting now!