# Error setting LaserLockBox settings in Multi-Intstument mode

**URL:** <https://forum.liquidinstruments.com/t/error-setting-laserlockbox-settings-in-multi-intstument-mode/1254>\
**Category:** Moku:Pro\
**Created:** [December 16, 2025, 12:49am UTC](https://forum.liquidinstruments.com/t/error-setting-laserlockbox-settings-in-multi-intstument-mode/1254 "2025-12-16T00:49:33Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![jephwack](https://avatars.discourse-cdn.com/v4/letter/j/47e85d/32.png) [@jephwack](https://forum.liquidinstruments.com/u/jephwack)\
**Post date:** [December 16, 2025, 12:49am UTC](https://forum.liquidinstruments.com/t/error-setting-laserlockbox-settings-in-multi-intstument-mode/1254/1 "2025-12-16T00:49:34Z")

</div>

Single instrument works as expected

```auto
from moku.instruments import LaserLockBox
LLB = LaserLockBox('moku.pro2.lab', force_connect=True, platform_id=4)
LLB.set_scan_oscillator(shape = 'NegativeRamp')

```

```auto
{'Output channel': 64,
 'Scan shape': 2,
 'amplitude': 0.5,
 'enabled': True,
 'frequency': 10.0,
 'output': 'AnalogOutput1',
 'shape': 'NegativeRamp'}

```

same request fails in multi instrument mode

```auto
from moku.instruments import LaserLockBox, MultiInstrument
MIM = MultiInstrument('moku.pro2.lab', force_connect=True, platform_id=4)
LLB = MIM.set_instrument(1, LaserLockBox)
LLB.set_scan_oscillator(shape = 'NegativeRamp')

```

```auto
---------------------------------------------------------------------------
InvalidParameterException Traceback (most recent call last)
Cell In[37], line 4
      2 MIM = MultiInstrument('moku.pro2.lab', force_connect=True, platform_id=4)
      3 LLB = MIM.set_instrument(1, LaserLockBox)
----> 4 LLB.set_scan_oscillator(shape = 'NegativeRamp')

File /opt/conda/envs/lab/lib/python3.13/site-packages/moku/instruments/_laserlockbox.py:242, in LaserLockBox.set_scan_oscillator(self, enable, shape, frequency, amplitude, output, strict)
    233 operation = "set_scan_oscillator"
    234 params = dict(
    235 strict=strict,
    236 enable=enable,
   (...) 240 output=output,
    241 )
--> 242 return self.session.post(
    243 f"slot{self.slot}/{self.operation_group}", operation, params
    244 )

File /opt/conda/envs/lab/lib/python3.13/site-packages/moku/session.py:23, in handle_response.<locals>.func_wrapper(self, *args, **kwargs)
     20 @wraps(func)
     21 def func_wrapper(self, *args, **kwargs):
     22 response = func(self, *args, **kwargs)
---> 23 return self.resolve(response)

File /opt/conda/envs/lab/lib/python3.13/site-packages/moku/session.py:204, in RequestSession.resolve(self, response)
    202 return data.data
    203 elif data.success is False:
--> 204 self._handle_error(data.code, data.messages)
    205 else:
    206 # Log the full response details for debugging
    207 logger.debug(f"HTTP error response: {response. __dict__ }")

File /opt/conda/envs/lab/lib/python3.13/site-packages/moku/session.py:158, in RequestSession._handle_error(code, messages)
    156 raise exceptions.NoInstrumentBitstream(messages)
    157 elif code == "INVALID_PARAM":
--> 158 raise exceptions.InvalidParameterException(messages)
    159 elif code == "INVALID_REQUEST":
    160 raise exceptions.InvalidRequestException(messages)

InvalidParameterException: ['AnalogOutput1 is not a valid value for Output channel']

```

---

<div class="post-metadata">

**Author:** ![Dylan](https://avatars.discourse-cdn.com/v4/letter/d/e95f7d/32.png) [@Dylan](https://forum.liquidinstruments.com/u/Dylan)\
**Post date:** [December 16, 2025, 3:15am UTC](https://forum.liquidinstruments.com/t/error-setting-laserlockbox-settings-in-multi-intstument-mode/1254/2 "2025-12-16T03:15:30Z")

</div>

Hello @jephwack ,

Thank you for reaching out to Liquid Instruments! This error is because `set_scan_oscillator()` has a parameter `output` that is by default `Output1`. In Multi-Instrument mode, the syntax changes to `Output A/B` which will have to be explicitly set (see documentation [here](https://apis.liquidinstruments.com/api/reference/llb/set_scan_oscillator.html)). Changing the line to `LLB.set_scan_oscillator(shape='NegativeRamp', output='OutputA')` should fix the error.

-Dylan

---

<div class="post-metadata">

**Author:** ![jephwack](https://avatars.discourse-cdn.com/v4/letter/j/47e85d/32.png) [@jephwack](https://forum.liquidinstruments.com/u/jephwack)\
**Post date:** [December 17, 2025, 1:38am UTC](https://forum.liquidinstruments.com/t/error-setting-laserlockbox-settings-in-multi-intstument-mode/1254/3 "2025-12-17T01:38:08Z")

</div>

Thanks, you suggestion works

```auto
from moku.instruments import LaserLockBox, MultiInstrument
MIM = MultiInstrument('moku.pro2.lab', force_connect=True, platform_id=4)
LLB = MIM.set_instrument(1, LaserLockBox)
LLB.set_scan_oscillator(output = 'OutputA' , shape = 'NegativeRamp')

```

```auto
{'Output channel': 96,
 'Scan shape': 2,
 'amplitude': 0.5,
 'enabled': True,
 'frequency': 10.0,
 'output': 'GenericOutputA',
 'shape': 'NegativeRamp'}

```

Passing invalid parameters as defaults should be considered a bug.

The documentation does not cover all the values we have seen, what is Analog vs Generic?

---

<div class="post-metadata">

**Author:** ![Dylan](https://avatars.discourse-cdn.com/v4/letter/d/e95f7d/32.png) [@Dylan](https://forum.liquidinstruments.com/u/Dylan)\
**Post date:** [December 18, 2025, 12:56am UTC](https://forum.liquidinstruments.com/t/error-setting-laserlockbox-settings-in-multi-intstument-mode/1254/4 "2025-12-18T00:56:28Z")

</div>

Hello @jephwack ,

In Multi-Instrument mode, the output can be routed to an analog output, or to another instrument; that is why it is referred to as ‘GenericOutputA/B’ vs in single instrument mode, the output is assigned to an analog output and referred to as ‘AnalogOutput1/2’. As far as the default parameters being invalid, I will discuss with my team how we can update the documentation to make this more clear. I hope this helps!

-Dylan