feat: add IT6000C eload driver (PyVISA) with manual control CLI

drivers/eload.py

@@ -0,0 +1,97 @@
+import time
+
+import pyvisa
+
+
+class EloadError(Exception):
+    pass
+
+
+class EloadConnectionError(EloadError):
+    pass
+
+
+class EloadCommunicationError(EloadError):
+    pass
+
+
+class Eload:
+    """ITECH IT6000C bi-directional supply, used here as an electronic load (CV mode with +/- current limit)."""
+
+    def __init__(self, resource_name, baud_rate=9600, timeout_ms=3000, retries=3, retry_delay_s=0.2):
+        self._retries = retries
+        self._retry_delay_s = retry_delay_s
+        try:
+            self._rm = pyvisa.ResourceManager()
+            self._inst = self._rm.open_resource(resource_name)
+        except pyvisa.VisaIOError as exc:
+            raise EloadConnectionError(f"failed to open {resource_name}") from exc
+
+        self._inst.baud_rate = baud_rate
+        self._inst.write_termination = "\n"
+        self._inst.read_termination = "\n"
+        self._inst.timeout = timeout_ms
+
+    def _write(self, cmd):
+        for attempt in range(self._retries):
+            try:
+                self._inst.write(cmd)
+                return
+            except pyvisa.VisaIOError as exc:
+                if attempt == self._retries - 1:
+                    raise EloadCommunicationError(f"write failed: {cmd!r}") from exc
+                time.sleep(self._retry_delay_s)
+
+    def _query(self, cmd):
+        for attempt in range(self._retries):
+            try:
+                return self._inst.query(cmd).strip()
+            except pyvisa.VisaIOError as exc:
+                if attempt == self._retries - 1:
+                    raise EloadCommunicationError(f"query failed: {cmd!r}") from exc
+                time.sleep(self._retry_delay_s)
+
+    def set_remote(self):
+        self._write("SYST:REM")
+
+    def set_local(self):
+        self._write("SYST:LOC")
+
+    def set_mode_cv(self):
+        self._write("SOUR:FUNC VOLT")
+
+    def set_mode_cc(self):
+        self._write("SOUR:FUNC CURR")
+
+    def set_voltage(self, volts):
+        self._write(f"VOLT {volts}")
+
+    def set_current(self, amps):
+        self._write(f"CURR {amps}")
+
+    def set_current_limit_positive(self, amps):
+        self._write(f"CURR:LIM:POS {amps}")
+
+    def set_current_limit_negative(self, amps):
+        self._write(f"CURR:LIM:NEG {amps}")
+
+    def output_on(self):
+        self._write("OUTP ON")
+
+    def output_off(self):
+        self._write("OUTP OFF")
+
+    def is_output_on(self):
+        return self._query("OUTP?") == "1"
+
+    def measure_voltage(self):
+        return float(self._query("MEAS:VOLT?"))
+
+    def measure_current(self):
+        return float(self._query("MEAS:CURR?"))
+
+    def measure_power(self):
+        return float(self._query("MEAS:POW?"))
+
+    def disconnect(self):
+        self._inst.close()