Powermeter example source documentation

1. import modules

from Licel import licel_tcpip, powermeter
import argparse

  • licel_tcpip: module required for communication with the ethernet controller.

  • powermeter: module providing the powermeter wrapper around powermeter-specific commands.

  • argparse: for parsing command line arguments in the example.

2. Command-line interface

The example uses a CLI helper to parse the following options:

argparser.add_argument('--ip', type=str, default = "10.49.234.234")
argparser.add_argument('--port', type=int, default=2055)
argparser.add_argument('--acq', type=int, default=100)
argparser.add_argument('--channel', type=int,  default=0)
argparser.add_argument('--internalTrigger', action=argparse.BooleanOptionalAction)

3. Initialize objects and open connections

Create the EthernetController and the powermeter instance and open both the command and push sockets:

ethernetController = licel_tcpip.EthernetController(ip, port)
Powermeter = powermeter.powermeter(ethernetController)

ethernetController.openConnection()
ethernetController.openPushConnection()

  • ethernetController.openConnection() — opens the command socket to the controller.

  • ethernetController.openPushConnection() — opens the push socket used for streaming data.

4. Verify device capability and select channel

Check that the controller supports the powermeter subcomponent and select the ADC channel:

print(ethernetController.getID())
capability = ethernetController.getCapabilities()
if capability.find('POW') == -1:
        raise RuntimeError("Missing capabilities POW")

print(Powermeter.selectChannel(channel))

  • ethernetController.getCapabilities() — returns a capability string that should contain “POW” if powermeter is supported.

  • Powermeter.selectChannel(channel) — selects the ADC input used for subsequent acquisitions (0 = photodiode, 2 = powermeter).

5. Optional: enable internal trigger

The example can enable the controller internal trigger simulation. Use when –internalTrigger is set:

if SimTrig:
        print(Powermeter.startInternalTrigger())

  • Powermeter.startInternalTrigger() — activates the internal trigger simulation.

6. Start acquisition loop (push mode)

Start push-mode acquisition and read lines from the push socket. In this mode the Powermeter will automatically send data on the push socket once started. The example reads ACQUISTION_CYCLES lines, each containing timestamp, pulse amplitude and trigger number:

print(Powermeter.Start())
for i in range(0, ACQUISTION_CYCLES):
        timestamp, pulseAmplitude, trigger_num = Powermeter.getPowermeterPushData()
        print(f"Pulse amplitude = {pulseAmplitude}, controller timestamp {timestamp} ms, trigger number {trigger_num}")
print(Powermeter.Stop())

  • Powermeter.Start() — starts powermeter push acquisition on the controller.

  • Powermeter.getPowermeterPushData() — returns a tuple (timestamp, pulseAmplitude, trigger_num) read from the push socket.

    • timestamp : EthernetController time since start in milliseconds.

    • pulseAmplitude : The calculated pulse amplitude of the acquired trace. The number represents the ADC raw value.

    • trigger_num : represents the trigger that caused the data to be collected.

  • Powermeter.Stop() — stops the powermeter push acquisition.

7. Acquire single-trace

Request a single trace over the command socket:

singleTraceData = Powermeter.getTrace()
print(singleTraceData)

  • Powermeter.getTrace() — requests a single trace over the command socket and returns a list of integer samples.

8. Disable internal trigger and close sockets

If an internal trigger was activated, stop it. Then shut down push and command sockets:

if SimTrig:
        print(Powermeter.stopInternalTrigger())

ethernetController.shutdownPushConnection()
ethernetController.shutdownConnection()

  • Powermeter.stopInternalTrigger() — stop internal trigger simulation.

  • ethernetcontroller.shutdownPushConnection() and shutdownConnection() — close push and command sockets respectively.