> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lagerdata.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Power Supply

> Control power supply on box

Control and monitor power supply Nets through the Lager CLI. Supports multi-vendor bench power supplies with voltage/current setting, protection thresholds, real-time monitoring via TUI, and concurrent access.

## Syntax

```bash theme={null}
lager supply [OPTIONS] NET_NAME COMMAND [ARGS]...
```

When invoked without a subcommand, lists all available power supply nets on the box:

```bash theme={null}
lager supply --box my-box
```

```
Name          Net Type       Instrument     Channel  Address
================================================================
PSU_CH1       power-supply   Rigol_DP832    CH1      USB0::0x1AB1::0x0E11::DP8...
PSU_CH2       power-supply   Rigol_DP832    CH2      USB0::0x1AB1::0x0E11::DP8...
DUT_POWER     power-supply   Keysight_E36312A  1     USB0::0x2A8D::0x1602::...
```

## Global Options

| Option       | Description                 |
| ------------ | --------------------------- |
| `--box TEXT` | Lagerbox name or IP address |
| `--help`     | Show help message and exit  |

## Commands

| Command     | Description                                                           |
| ----------- | --------------------------------------------------------------------- |
| `voltage`   | Set or read output voltage with optional protection thresholds        |
| `current`   | Set or read output current with optional protection thresholds        |
| `enable`    | Enable power output (requires confirmation)                           |
| `disable`   | Disable power output (requires confirmation)                          |
| `state`     | Show current power state including measurements and protection status |
| `clear-ovp` | Clear over-voltage protection fault                                   |
| `clear-ocp` | Clear over-current protection fault                                   |
| `set`       | Set power supply mode                                                 |
| `tui`       | Launch interactive terminal UI for real-time monitoring and control   |

## CLI Validation Ranges

The CLI enforces conservative upper bounds before sending commands to hardware:

| Parameter | Maximum | Notes                            |
| --------- | ------- | -------------------------------- |
| Voltage   | 100.0 V | Most bench supplies are 30-60 V  |
| Current   | 30.0 A  | Typical bench supply limit       |
| OVP       | 110.0 V | Can be slightly above max output |
| OCP       | 33.0 A  | Can be slightly above max output |

All values must be positive. OVP must be greater than or equal to the voltage setpoint.

## Command Reference

### `voltage`

Set or read output voltage with optional protection thresholds.

```bash theme={null}
lager supply NET_NAME voltage [VALUE] [OPTIONS]
```

**Arguments:**

* `VALUE` - Voltage in volts. Omit to read the current voltage setting.

**Options:**

| Option        | Type   | Description                                            |
| ------------- | ------ | ------------------------------------------------------ |
| `--ovp FLOAT` | Volts  | Over-voltage protection threshold (must be >= voltage) |
| `--ocp FLOAT` | Amps   | Over-current protection threshold                      |
| `--yes`       | Flag   | Apply without confirmation prompt                      |
| `--box TEXT`  | String | Lagerbox name or IP                                    |

When VALUE is provided, the CLI prompts for confirmation unless `--yes` is passed:

```
Set voltage to 3.3 V? [y/N]:
```

**Examples:**

```bash theme={null}
# Read current voltage
lager supply PSU voltage

# Set voltage to 3.3V (will prompt for confirmation)
lager supply PSU voltage 3.3

# Set voltage with automatic confirmation
lager supply PSU voltage 3.3 --yes

# Set voltage with OVP and OCP thresholds
lager supply PSU voltage 3.3 --ovp 3.6 --ocp 0.5 --yes
```

### `current`

Set or read output current with optional protection thresholds.

```bash theme={null}
lager supply NET_NAME current [VALUE] [OPTIONS]
```

**Arguments:**

* `VALUE` - Current in amps. Omit to read the current limit setting.

**Options:**

| Option        | Type   | Description                                            |
| ------------- | ------ | ------------------------------------------------------ |
| `--ovp FLOAT` | Volts  | Over-voltage protection threshold                      |
| `--ocp FLOAT` | Amps   | Over-current protection threshold (must be >= current) |
| `--yes`       | Flag   | Apply without confirmation prompt                      |
| `--box TEXT`  | String | Lagerbox name or IP                                    |

When VALUE is provided, the CLI prompts for confirmation unless `--yes` is passed:

```
Set current to 1.0 A? [y/N]:
```

**Examples:**

```bash theme={null}
# Read current limit
lager supply PSU current

# Set current limit to 1A
lager supply PSU current 1.0 --yes

# Set current with protection thresholds
lager supply PSU current 1.0 --ocp 1.2 --ovp 5.0 --yes
```

### `enable`

Enable power output to device. Requires confirmation to prevent accidental power-on.

```bash theme={null}
lager supply NET_NAME enable [OPTIONS]
```

**Options:**

| Option       | Description                        |
| ------------ | ---------------------------------- |
| `--yes`      | Enable without confirmation prompt |
| `--box TEXT` | Lagerbox name or IP                |

```
Enable Net? [y/N]:
```

### `disable`

Disable power output. Requires confirmation to prevent accidental power-off.

```bash theme={null}
lager supply NET_NAME disable [OPTIONS]
```

**Options:**

| Option       | Description                         |
| ------------ | ----------------------------------- |
| `--yes`      | Disable without confirmation prompt |
| `--box TEXT` | Lagerbox name or IP                 |

```
Disable Net? [y/N]:
```

### `state`

Show comprehensive power supply state including measurements, setpoints, and protection status.

```bash theme={null}
lager supply NET_NAME state [--box TEXT]
```

**Example output (Rigol DP800):**

```
Channel: CH1
Enabled: ON
Mode: CV
Voltage: 3.3000
Current: 0.1520
Power: 0.5016
OCP Limit: 1.0000
    OCP Tripped: NO
OVP Limit: 3.6000
    OVP Tripped: NO
```

Fields:

* **Channel** - Active channel on multi-channel supplies
* **Enabled** - Output ON or OFF
* **Mode** - CV (constant voltage) or CC (constant current)
* **Voltage/Current/Power** - Live measurements (4 decimal places)
* **OCP/OVP Limit** - Protection thresholds
* **OCP/OVP Tripped** - Whether protection has triggered (color-coded: green=NO, red=YES)

### `clear-ovp`

Clear over-voltage protection fault. Use after an OVP trip to reset the protection and allow the output to be re-enabled.

```bash theme={null}
lager supply NET_NAME clear-ovp [--box TEXT]
```

### `clear-ocp`

Clear over-current protection fault. Use after an OCP trip to reset the protection and allow the output to be re-enabled.

```bash theme={null}
lager supply NET_NAME clear-ocp [--box TEXT]
```

### `set`

Set power supply mode. The available modes depend on the hardware.

```bash theme={null}
lager supply NET_NAME set [--box TEXT]
```

### `tui`

Launch an interactive terminal UI for real-time power supply monitoring and control. The TUI provides live-updating measurements, inline command entry, and keyboard shortcuts.

```bash theme={null}
lager supply NET_NAME tui [--box TEXT]
```

Requires the `textual` Python package (`pip install textual`).

**TUI display:**

* Live voltage, current, and power measurements (updated every second)
* Output status (ON/OFF) with color coding
* Mode indicator (CV/CC) with color coding
* Protection thresholds and trip status
* Hardware maximum ratings
* Scrollable command log

**TUI commands** (enter at the prompt):

| Command               | Description               |
| --------------------- | ------------------------- |
| `voltage [VALUE]`     | Set or read voltage       |
| `current [VALUE]`     | Set or read current limit |
| `ocp [VALUE]`         | Set or read OCP threshold |
| `ovp [VALUE]`         | Set or read OVP threshold |
| `enable`              | Enable output             |
| `disable`             | Disable output            |
| `state`               | Display current state     |
| `clear-ocp`           | Clear OCP trip            |
| `clear-ovp`           | Clear OVP trip            |
| `help`                | Show available commands   |
| `clear`               | Clear the command log     |
| `q` / `quit` / `exit` | Exit the TUI              |

**Keyboard shortcuts:**

| Key            | Action                   |
| -------------- | ------------------------ |
| `q`            | Quit                     |
| `Ctrl+C`       | Quit                     |
| `r`            | Refresh display          |
| Up/Down arrows | Navigate command history |

**Concurrent access:** While the TUI is running, other `lager supply` CLI commands (e.g., `lager supply PSU voltage 3.3 --yes`) will automatically route through the TUI's WebSocket connection on port 9000, sharing the USB instrument connection. If the TUI is not running, commands use direct USB access.

## OVP / OCP Protection

Over-voltage protection (OVP) and over-current protection (OCP) thresholds protect your device under test from damage.

**Setting thresholds:**

```bash theme={null}
# Set OVP and OCP when setting voltage
lager supply PSU voltage 3.3 --ovp 3.6 --ocp 0.5 --yes

# Set OCP when setting current
lager supply PSU current 1.0 --ocp 1.2 --yes
```

**Validation rules:**

* All values must be positive
* OVP must be >= the voltage setpoint
* OCP must be >= the current setpoint
* Values are validated against CLI maximum limits before being sent to hardware

**When protection trips:**

1. The supply output is disabled automatically
2. `state` shows the tripped status in red
3. Clear the fault with `clear-ovp` or `clear-ocp`
4. Re-enable the output with `enable`

**Automatic OVP management (Rigol):** When setting a new voltage that would exceed the current OVP limit, the driver temporarily raises OVP by 10% headroom, sets the new voltage, then restores the desired OVP. This prevents false trips during voltage changes.

## Supported Hardware

| Manufacturer | Model Series   | Channels | Specs                      | Notes                  |
| ------------ | -------------- | -------- | -------------------------- | ---------------------- |
| Rigol        | DP832 / DP832A | 3        | Ch1-2: 30V/3A, Ch3: 5V/3A  | Most common            |
| Rigol        | DP821          | 2        | Ch1: 60V/1A, Ch2: 8V/10A   |                        |
| Rigol        | DP811 / DP811A | 1        | 20V/10A or 40V/5A (range)  |                        |
| Keithley     | 2281S          | 1        | 20V/6A/120W                | Battery simulator mode |
| Keysight     | E36200 series  | 2        | E36233A: 30V/20A per ch    | Dual output            |
| Keysight     | E36300 series  | 3        | E36311A/12A/13A            | Triple output          |
| EA           | PSI/EL series  | 1        | PSB 10080-60, PSB 10060-60 | Two-quadrant           |

Multi-channel supplies use the channel number configured in the net record. Each channel is typically configured as a separate net.

## Default Net

Set a default power supply net to avoid specifying the name each time:

```bash theme={null}
lager defaults add --supply-net PSU
```

Then commands can omit the net name:

```bash theme={null}
lager supply voltage 3.3 --yes
lager supply state
```

## Examples

```bash theme={null}
# List all power supply nets
lager supply --box my-box

# Set voltage with protection
lager supply PSU voltage 3.3 --ovp 3.6 --ocp 0.5 --yes

# Set current limit
lager supply PSU current 1.0 --ocp 1.2 --yes

# Enable output (skip confirmation)
lager supply PSU enable --yes

# Check state
lager supply PSU state

# Disable output
lager supply PSU disable --yes

# Clear protection faults
lager supply PSU clear-ovp
lager supply PSU clear-ocp

# Launch interactive TUI
lager supply PSU tui
```

### Scripting Example

```bash theme={null}
#!/bin/bash
# Power cycle a device under test
BOX="my-box"
NET="DUT_POWER"

lager supply $NET voltage 3.3 --ovp 3.6 --ocp 0.5 --yes --box $BOX
lager supply $NET enable --yes --box $BOX
sleep 2

# Run tests while powered
lager python test_script.py --box $BOX

# Power down
lager supply $NET disable --yes --box $BOX
```

## Troubleshooting

| Error                    | Cause                                    | Fix                                             |
| ------------------------ | ---------------------------------------- | ----------------------------------------------- |
| "Resource busy"          | TUI is using the supply's USB connection | Close the TUI (press `q`), then retry           |
| "No route to host"       | Box unreachable                          | Check VPN/Tailscale: `lager hello --box <box>`  |
| Connection refused       | Box service not running                  | Verify box is online: `lager hello --box <box>` |
| OVP/OCP validation error | Protection threshold below setpoint      | Set OVP >= voltage, OCP >= current              |
| "exceeds maximum limit"  | Value above CLI safety limits            | Check equipment specs; CLI max is 100V / 30A    |

## Notes

* All `voltage` and `current` set operations require confirmation (use `--yes` to skip)
* `enable` and `disable` also require confirmation
* Net names refer to names assigned when setting up your testbed with `lager nets`
* The TUI connects via WebSocket (port 9000) for real-time updates
* Protection thresholds help prevent damage to your device under test
* Multi-channel supplies: each channel is configured as a separate net

## See Also

* [Battery Simulation](/source/reference/cli/battery) -- Control battery simulators (Keithley 2281S)
* [Electronic Load](/source/reference/cli/eload) -- Programmable electronic loads
* [Watt Meter](/source/reference/cli/watt) -- Power measurement with Yocto-Watt and Joulescope
* [Python Supply API](/source/reference/python/supply) -- Automate power supply control in Python scripts