Simple python script for demonstrating SCPI programming

Documentation/UserManual/SCPI_Examples/.gitignore

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+venv/
+__pycache__
+.idea
+

Documentation/UserManual/SCPI_Examples/libreVNA.py

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+import socket
+from asyncio import IncompleteReadError  # only import the exception class
+
+class SocketStreamReader:
+    def __init__(self, sock: socket.socket):
+        self._sock = sock
+        self._recv_buffer = bytearray()
+
+    def read(self, num_bytes: int = -1) -> bytes:
+        raise NotImplementedError
+
+    def readexactly(self, num_bytes: int) -> bytes:
+        buf = bytearray(num_bytes)
+        pos = 0
+        while pos < num_bytes:
+            n = self._recv_into(memoryview(buf)[pos:])
+            if n == 0:
+                raise IncompleteReadError(bytes(buf[:pos]), num_bytes)
+            pos += n
+        return bytes(buf)
+
+    def readline(self) -> bytes:
+        return self.readuntil(b"\n")
+
+    def readuntil(self, separator: bytes = b"\n") -> bytes:
+        if len(separator) != 1:
+            raise ValueError("Only separators of length 1 are supported.")
+
+        chunk = bytearray(4096)
+        start = 0
+        buf = bytearray(len(self._recv_buffer))
+        bytes_read = self._recv_into(memoryview(buf))
+        assert bytes_read == len(buf)
+
+        while True:
+            idx = buf.find(separator, start)
+            if idx != -1:
+                break
+
+            start = len(self._recv_buffer)
+            bytes_read = self._recv_into(memoryview(chunk))
+            buf += memoryview(chunk)[:bytes_read]
+
+        result = bytes(buf[: idx + 1])
+        self._recv_buffer = b"".join(
+            (memoryview(buf)[idx + 1 :], self._recv_buffer)
+        )
+        return result
+
+    def _recv_into(self, view: memoryview) -> int:
+        bytes_read = min(len(view), len(self._recv_buffer))
+        view[:bytes_read] = self._recv_buffer[:bytes_read]
+        self._recv_buffer = self._recv_buffer[bytes_read:]
+        if bytes_read == len(view):
+            return bytes_read
+        bytes_read += self._sock.recv_into(view[bytes_read:])
+        return bytes_read
+
+class libreVNA:
+    def __init__(self, host='localhost', port=19542):
+        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        try:
+            self.sock.connect((host, port))
+        except:
+            raise Exception("Unable to connect to LibreVNA-GUI. Make sure it is running and the TCP server is enabled.")
+        self.reader = SocketStreamReader(self.sock)
+
+    def __del__(self):
+        self.sock.close()
+
+    def __read_response(self):
+        return self.reader.readline().decode().rstrip()
+
+    def cmd(self, cmd):
+        self.sock.sendall(cmd.encode())
+        self.sock.send(b"\n")
+        self.__read_response()
+
+    def query(self, query):
+        self.sock.sendall(query.encode())
+        self.sock.send(b"\n")
+        return self.__read_response()

Documentation/UserManual/SCPI_Examples/simple_generator_control.py

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+#!/usr/bin/env python3
+
+import time
+from libreVNA import libreVNA
+
+# Create the control instance
+vna = libreVNA('localhost', 19542)
+
+# Quick connection check (should print "LibreVNA-GUI")
+print(vna.query("*IDN?"))
+
+# Make sure we are connecting to a device (just to be sure, with default settings the LibreVNA-GUI auto-connects)
+vna.cmd(":DEV:CONN")
+dev = vna.query(":DEV:CONN?")
+if dev == "Not connected":
+    print("Not connected to any device, aborting")
+    exit(-1)
+else:
+    print("Connected to "+dev)
+
+# Simple generator demo
+
+# switch to generator
+vna.cmd(":DEV:MODE GEN")
+
+# set the output level
+vna.cmd(":GEN:LVL -20")
+
+# set initial frequency and enable port 1
+print("Generating signal with 1GHz at port 1")
+vna.cmd(":GEN:FREQ 1000000000")
+vna.cmd(":GEN:PORT 1")
+
+try:
+    while True:
+        time.sleep(2)
+        print("Setting frequency to 1.5GHz")
+        vna.cmd(":GEN:FREQ 1500000000")
+        time.sleep(2)
+        print("Setting frequency to 1.0GHz")
+        vna.cmd(":GEN:FREQ 1000000000")
+except KeyboardInterrupt:
+    # turn off generator
+    vna.cmd(":GEN:PORT 0")
+    exit(0)
+