Multimeter Device - MP730027 Driver

Digital multimeter control library with support for voltage, current, resistance, continuity, and temperature measurements using SCPI protocol over Ethernet.

Device Info

Model: Multicomp-Pro MP730027
Type: Digital Multimeter
Interface: Ethernet (TCP Socket)
Default Port: 3000
Protocol: SCPI (Standard Commands for Programmable Instruments)

Installation

The MP730027 driver is part of the multimeter_device package:

from multimeter_device import MP730027

Quick Start

from multimeter_device import MP730027

# Connect to multimeter
mm = MP730027("192.168.1.99", port=3000)

# Measure DC voltage
voltage = mm.measure_dc_voltage()
print(f"DC Voltage: {voltage}V")

# Measure resistance
resistance = mm.measure_resistance()
print(f"Resistance: {resistance}Ω")

# Generic measurement
result = mm.measure("ac_current")
print(f"AC Current: {result['value']}A")

API Reference

Initialization

mm = MP730027(ip, port=3000, timeout=2)

Parameters:

ip (str): Device IP address
port (int): TCP port (default: 3000)
timeout (float): Socket timeout in seconds (default: 2)

Voltage Measurements

`measure_dc_voltage() -> str`

Measure DC voltage (V).

voltage = mm.measure_dc_voltage()
# Returns: "5.00" (as string)

`measure_ac_voltage() -> str`

Measure AC voltage (V).

voltage = mm.measure_ac_voltage()
# Returns: "230.5" (as string)

Current Measurements

`measure_dc_current() -> str`

Measure DC current (A).

current = mm.measure_dc_current()
# Returns: "0.50" (as string)

`measure_ac_current() -> str`

Measure AC current (A).

current = mm.measure_ac_current()
# Returns: "1.23" (as string)

Resistance & Continuity

`measure_resistance() -> str`

Measure resistance (Ω).

resistance = mm.measure_resistance()
# Returns: "1500" (as string, in ohms)

`measure_continuity() -> str`

Test continuity (beeps if resistance < 50Ω).

result = mm.measure_continuity()
# Returns: "0" (beeps) or "1" (open circuit)

Temperature

`measure_temperature() -> str`

Measure temperature (°C). Requires probe sensor connected.

temp = mm.measure_temperature()
# Returns: "25.3" (as string, in Celsius)

Generic Measurement

`measure(mode: str) -> dict`

Unified interface for all measurement types.

result = mm.measure("dc_voltage")
# Returns: {"mode": "dc_voltage", "value": "5.00"}

Supported Modes:

"dc_voltage" - DC voltage measurement
"ac_voltage" - AC voltage measurement
"dc_current" - DC current measurement
"ac_current" - AC current measurement
"resistance" - Resistance measurement
"continuity" - Continuity test
"temperature" - Temperature measurement

Returns:

{
    "mode": str,      # The measurement mode used
    "value": str      # The measured value
}

Low-Level IO

For advanced usage or custom SCPI commands:

`write(cmd: str)`

Send command to device (no response expected).

mm.write("CONF:VOLT:DC")

`query(cmd: str) -> str`

Send command and retrieve response.

response = mm.query("MEAS:VOLT:DC?")

REST API

Flask-based HTTP interface for remote access.

Starting the Server

cd multimeter_device
python -m flask --app flask_app run --port 5001

Server runs on http://localhost:5001

API Endpoints

`POST /measure`

Measure with specified mode.

Request:

{
  "mode": "dc_voltage"
}

Response:

{
  "mode": "dc_voltage",
  "value": "5.00"
}

`GET /measure/<mode>`

Quick measurement with mode in URL.

Request:

GET /measure/dc_voltage
GET /measure/resistance
GET /measure/ac_current

Response:

{
  "mode": "dc_voltage",
  "value": "5.00"
}

Valid Modes:

dc_voltage, ac_voltage
dc_current, ac_current
resistance, continuity, temperature

Common Patterns

Multi-Measurement Reading

measurements = {
    "dc_voltage": mm.measure_dc_voltage(),
    "dc_current": mm.measure_dc_current(),
    "resistance": mm.measure_resistance(),
}

for name, value in measurements.items():
    print(f"{name}: {value}")

Continuous Monitoring

import time

for i in range(10):
    voltage = mm.measure_dc_voltage()
    print(f"Reading {i+1}: {voltage}V")
    time.sleep(1)

Convert to Float

voltage_str = mm.measure_dc_voltage()
voltage_float = float(voltage_str)
print(f"Type: {type(voltage_float)}, Value: {voltage_float}")

Verify Connection

try:
    voltage = mm.measure_dc_voltage()
    print("Connected!")
except:
    print("Connection failed")

Device-to-Device Coordination

See demo.py for example of using multimeter to verify PSU output:

from psu_device import MP711001
from multimeter_device import MP730027

psu = MP711001("192.168.1.100")
mm = MP730027("192.168.1.99", port=3000)

# Set PSU and verify with multimeter
psu.set_voltage(1, 5.0)
psu.output_on(1)

import time
time.sleep(2)  # Wait for stabilization

measured = mm.measure_dc_voltage()
print(f"Set: 5.0V, Measured: {measured}V")

Error Handling

The driver automatically reconnects on socket errors. No explicit error handling required in most cases.

For custom error handling:

try:
    voltage = mm.measure_dc_voltage()
except ValueError as e:
    print(f"Invalid mode: {e}")
except Exception as e:
    print(f"Measurement error: {e}")
    # Driver will attempt reconnect on next command

Performance Notes

Timing: 0.15-0.2s delay between commands for stability
Measurement: Single-shot, blocking. No polling loops.
Reconnection: ~0.5s delay on error recovery
Response Format: All measurements return strings (convert with float() as needed)

Specifications

Typical multimeter specifications (refer to device manual for exact values):

Voltage Range: 0-1000V AC/DC
Current Range: 0-10A AC/DC
Resistance Range: 0-100MΩ
Display Resolution: 3-4 digits typical
Accuracy: ±0.5-1% typical

Troubleshooting

"Connection refused"

Check device IP address: ping 192.168.1.99
Verify device is powered on
Confirm port 3000 is not blocked by firewall

"Socket timeout"

Device may be slow; try increasing timeout parameter
Check network latency
Ensure probe connections are secure

"Invalid mode" error

Check mode spelling (use constants or list from docstring)
Verify mode is supported by device

Measurements reading zero

Check probe connections
Verify measurement range for device
Try a known voltage source to verify device operation

Temperature sensor not working

Confirm temperature probe is connected
Some devices require probe to be recognized before use
Check device manual for probe specifications

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