The setup and calibration of the PLD is done via the ELD Assignment Tab of the amplifier. The configuration for the PLD triggering failover is done via the Options tab > ELD Fault Triggers Failover.
PLD’s can be enabled on a per channel basis by the checkbox in the PLD column. Configuration of a PLD device is a two-step process, first you need to enable a PLD on a channel, and second you need to run the characterisation/detection process. The characterization process will allow the amplifier to detect the PLD on the speaker line. The PLD detection is performed by pressing one of the ‘Calibrate’ or ‘Recalibrate All’ buttons. This will trigger all channels with a PLD configured to perform a characterisation/detection cycle with pink noise. After the pink noise, the impedance curve for this frequency area will be used to determine the centre frequency to be used. Once the centre frequency is found, a Tone Test will be performed to calculate the nominal impedance and bandwidth for the PLD. This information will then be used to configure the Impedance Monitoring Band which is used to detect the PLD. If the PLD cannot be found in the impedance curve then the PLD status will show ‘PLD Detection Failed’. The button ‘Recalibrate All’ will allow calibration on all channels configured to use PLD’s even if they have been calibrated already. The Status column will display the state of the PLD before, during and after the calibration/detection process.
| Status | System | Color | Description |
| Requires Calibration | Online / Offline | Yellow | PLD requires calibration on this channel. |
| Detecting | Online | White | The amplifier is applying pink noise over the PLD frequencies to determine the PLD center frequency notch. |
| Calibrating | Online | White | PLD calibration is being performed. |
| Calibrated | Offline | White | The PLD was calibrated correctly. |
| Calibrated | Online | White | The line is being measured and a result is not yet available |
| PLD Detection Failed | Online / Offline | Red | The PLD detection or calibration process failed. |
| Connected | Online | Green | The PLD has been detected on the speaker line. |
| Channel Failure | Online | Red | The PLD couldn't be found on the speaker line. |
Each channel of an amplifier can be configured to use Impedance Monitoring in conjunction with Vocia ELD-1's, or a Vocia PLD device to monitor the integrity of the speaker line, but not both.
When a PLD-1 is configured and enabled on a VA-8600(c) three Impedance Monitoring Bands are available. When using a PLD-2 on a VA-4300CV or a VA-8150CV four monitoring bands are available.
The PLD model used must be matched with the correct host device for proper operation and reporting of faults. A PLD device can be identified by the color of its lead. The lead on a PLD-1 is white and the lead on a PLD-2 is yellow.
It is permissible to use a mixture of ELD-1's and PLD's across different amplifier channels.
PLD devices monitor the integrity of the speaker lines connected to each output channel. Any loss of device will be reported as a speaker line fault and if ELD Fault Triggers Failover is enabled, this will cause failover to occur.
In contrast to most other devices in the Vocia product range, PLD's do not require the setting of a Device ID or require a network connection.