get - Get Channel Value

Description

The get command retrieves the current value of a specific channel with performance metrics. It can capture multiple samples and provides detailed timing statistics.

Syntax

get --channel <channel_name> [options]

Required Options

Optional Options

Examples

Single Sample

get --channel "VOLTAGE_SENSOR_1"

Multiple Samples with Statistics

get --channel "TEMPERATURE_1" --samples 100

Using Short Options

get -c "ADC_CH0" -s 1000

With Interval Between Samples

get -c "TEMPERATURE" -s 100 -i 100

With Detailed Timing Analysis

get -c "VOLTAGE" -s 50 -d

Logging to CSV File

get -c "CURRENT_SENSE" -s 1000 -l "latency_log.csv"

Combined Options

get -c "ADC_CH0" -s 500 -i 10 -l "adc_timing.csv" -d

Output Format

Single Sample

Reading channel: VOLTAGE_SENSOR_1

3.3000 (2.15 ms)

Multiple Samples

Reading channel: VOLTAGE_SENSOR_1

3.3001 (2.10 ms)
3.3002 (2.15 ms)
3.2999 (2.18 ms)
...

Average: 2.14 ms over 100 samples

With Detailed Analysis

Reading channel: VOLTAGE_SENSOR_1
Detailed network timing analysis enabled

3.3001 (2.10 ms)
...

CSV Log Output

When using --log-file, the CSV file contains:

Timestamp,Channel,LatencyMs
2024-01-15 10:30:45.123,ADC_CH0,2.150
2024-01-15 10:30:45.235,ADC_CH0,2.120
...

Output Colors

Channel names and values are colored by channel type (matching the GUI):

• Values are displayed with type-specific colors via ColorHelper
• Each sample shows timing in dim text: (2.15 ms)
• Yellow text indicates detailed analysis mode enabled
• Magenta text shows average statistics for multiple samples

Performance Metrics

The command provides timing information:

Additional features:

• Detailed analysis: Enabled with -d flag, shows network timing breakdown
• CSV logging: Records timestamp, channel name, and latency for each sample
• Interval delays: Optional delay between samples using -i option

Behavior

1. Resolves channel name using regex matching
2. Displays channel being read with type-specific color
3. Shows detailed analysis notice if -d flag is used
4. Opens CSV log file if -l specified (creates with header if new)
5. For each sample:
   • Records start time
   • Calls GetValue on the channel
   • Records end time and calculates duration
   • Displays value with timing
   • Logs to CSV if enabled
   • Waits for interval if specified and not last sample
6. After all samples, shows average if samples > 1
7. Closes CSV log file if used

Channel Name Resolution

The command uses regex matching to find channels:

• If VOLTAGE is provided, it matches the first channel containing "VOLTAGE"
• For exact matching, use the full channel name
• Uses GetFirstChannelNameFromRegex() internally

Use Cases

Performance Testing

# Test acquisition speed with logging
get -c "FAST_ADC" -s 10000 -l "performance_test.csv"

Value Monitoring with Interval

# Monitor voltage every 100ms
get -c "VDD_CORE" -s 1000 -i 100

Network Timing Analysis

# Analyze network latency
get -c "SENSOR" -s 100 -d

Long-term Logging

# Log data over time (appends to existing file)
get -c "TEMPERATURE" -s 5000 -i 1000 -l "temp_log.csv"

Notes

• Requires an active connection (use init first)
• Samples are captured sequentially (not parallel)
• Timing includes network/communication overhead
• Large sample counts may take significant time

Performance Considerations

• Sample acquisition time varies by channel type:

  • Fast: Digital I/O (< 1 ms)
  • Medium: ADC channels (2-5 ms)
  • Slow: Complex calculations (> 10 ms)

• Network latency affects timing:

  • Local network: 1-5 ms overhead
  • Remote network: 10-100 ms overhead

Error Handling

Common errors:

• Channel not found: Check channel name or use list to see available channels
• Not connected: Run init command first
• Timeout: Channel may not be responding

See Also

• set - Set channel values
• list - List all available channels
• wait - Wait for channel to reach specific value
• num - For statistical analysis of numeric channels