Crown Audio PIP-Lite Module - Manual (Page 34)

Networked PIP Series
page 34 Reference Manual
5.2.24 Load Supervision
The load supervision feature allows real-time monitoring of the load connected to each
amplifier channel. When enabled, the PIP continuously monitors the amplifier output voltage
and current, and calculates the long-term average load impedance. The measured load
impedance is compared against the user-defined high and low limits. If either limit is
exceeded, the status indicator and, if enabled, the IQwic Error Reporting functions alert the
user of the problem. There are six controls and two indicators for each channel:
Enable: Enables or disables the load-supervision function.
High Limit: Sets the upper bound above which the system will report a “high” error status.
Low Limit: Sets the lower bound below which the system will report a “low” error status.
Nominal Load Impedance: Sets the expected average impedance for the connected load.
This value determines the output signal level required for the test. This parameter is also
used by the average power limiter to determine the expected power threshold. (See Section
4.2.25).
Report Error to Network: Enables Error Reporting to send an error report via the network
so that high and low load conditions are reported to the software. (See Section 4.2.18).
Report Error to Aux: Enables and high or low load error to be reported by the AUX output.
(See Sections 4.2.18 and 6.1.)
Test Indicator: This indicator is active when the amplifier output signal is sufficient to
allow load impedance calculation and test verification.
Low/Normal/High Indicator: This indicator shows the present status of the load imped-
ance with respect to the user-defined high and low limits.
Z Average Monitor: Reports the actual calculated average load impedance in ohms. Its
range is from 0 ohms to 250 ohms.
Load Supervision Applications
The Load Supervision feature can be used to monitor the amplifier load in real time with
almost any program material. Average load impedance is calculated as a function of ampli-
fier output voltage and current. This function is different from the SLM feature as it uses the
program material to calculate. The system requires approximately 20-30 mA of average
amplifier output current for adequate supervision. This allows typically low average output
power levels of less than ½ watt with most loads. The maximum load impedance for reliable
system performance is limited to about 50 ohms. Higher impedances can be measured but
may require higher amplifier output levels for reliable operation.