Lab.gruppen PLM 20000Q - Manual (Page 99)

Application Guide
93
PLM Series Operation Manual rev 1.2.3
10.6.3 Connections and Cabling
10.6.3.1 Input and Link Connectors
An AES3 input signal is connected to the XLR3F connector labelled INPUT 1-2 in the AES3 input section
on the rear panel. An XLR3M connector, labelled LINK 1-2 is provided as a loop-through output for daisy-
chaining multiple PLM Series devices.
The Input and Link connectors are identical for the analog and digital inputs, so care must be taken when
connecting audio, particularly when analog inputs are used as a backup signal source. Connectors should be
clearly labeled to prevent any confusion.
Never connect a digital signal source to an analog input or an
analog signal source to a digital input.
10.6.3.2 Interconnection Options
If multiple PLM Series devices are receiving the same AES3 signal, connections may be configured in two
ways:
1. Daisy-Chain – Connect the signal source (e.g. mixing console, digital snake or distribution amplifier)
to the AES3 input on the first PLM. Connect the adjacent Link output on the same unit to the Input
on the next PLM, and continue connecting in this manner. Up to 20 PLM units may be daisy-chained
in this manner, though the total may be dependent on environmental conditions and the quality of
connecting cables.
2. AES3 Distribution Amplifier – Connect the input of the distribution amplifier to the signal source, and
connect the outputs individually to the PLMs. The number of available outputs must be equal to or
greater than the number of PLM devices to be driven. The distribution amplifier must be specifically
designed for AES3 signals; a device made for analog signals will not function in this capacity. Please
refer to section 10.6.4 for further information.
Consider the application requirements carefully before choosing an interconnection configuration. Note that
the daisy-chain option presents a potential single-point-of-failure scenario; failure of one cable or connection
will affect all subsequent devices in the chain. Use of distribution amplifiers avoids this scenario, although
extra expense is involved and potential failure of the distribution amplifier itself is introduced.
10.6.3.3 Cable Types and Distance Limitations
All digital connections should be made with 100 ohm balanced cables wired according to the AES3
standard (see Figure 8-11 on page 68). Although standard analog microphone cabling may function in limited
circumstances, the potential for problems is greatly increased. AES3 contains a high-speed data stream, and
requires an effective bandwidth of up to 12 MHz, far beyond the 20 kHz required for analog audio.