9.345 Matrix-Protection-Switcher

This page describes the device driver and the device window for the Matrix-Protection-Switcher logical device. This device lets you use a switch matrix to select the input signal(s) for the backup signal chain in a N:1 redundant configuration controlled by a Protection-Switch-N-To-1 device.

The Matrix-Protection-Switcher provides a 'position' parameter which may be commanded to OFF, 1, 2, 3 ... n. Each numbered selection routes the input signal(s) from this chain to the backup chain. OFF switches the signal at the input off.

The Matrix-Protection-Switcher does not act like a simple N:1 switch, it is aware of the type of switch matrix used (distributive, combining ot crosspoint based), evaluates which signals the matrix actually routes to the signal chain to substitute and replicates this matrix settings for the output connected to the backup chain.

Distributive matrix switching behavior

A distributive matrix permits each output to select exactly one input signal. When the Matrix-Protection-Switcher switches to position n with such a matrix, it looks up which input signal is set for the output connected to chain n and replicates this setting for the output to the backup chain. When switching to OFF, the Matrix-Protection-Switcher simply switches off the signal to the backup chain.

Crosspoint based matrix switching behavior

A crosspoint based switch matrix permits to select an arbitrary combination of input signals for every output. The output signal is the sum of all input signals routed to it. When the Matrix-Protection-Switcher switches to position n with such a matrix, it looks up which crosspoints are set for the output connected to chain n and replicates this setting for the output to the backup chain. When switching to OFF, the Matrix-Protection-Switcher switches off all crosspoints for the output connected to the backup chain.

Combining matrix switching behavior

A combining matrix permits each input to select exactly one output to route the signal to. The output signal is the sum of all input signals routed to it. When the Matrix-Protection-Switcher switches with such a matrix to position n, it looks up which inputs are actually routed to chain n and switches these inputs to the backup chain. Chain n is without input signals after this. When switching to OFF, the Matrix-Protection-Switcher switches off all inputs which actually are connected to the backup chain.

The combining matrix looses the information which inputs were routed to to the operational chain after switching them to the backup chain. For this reason switching to chain n is a one shot operation with this matrix type. In case of a fault in one of the operational chains its signals are switched by the Protection-Switch-N-To-1 device to the backup chain. Switching back however must be done manually by commanding the switch matrix directly.

Device window pages

The following table shows which device window pages are available with this individual device type. Tool-bar functions not mentioned here are described at the general description of device windows .

• --- The switch position.
• --- The faults page.
• --- The device info page.
• --- The maintenance page. The configuration parameters described below are set at this page.

Configuration parameters

At the maintenance page of the device window there are a couple of configuration parameters which must be set to integrate the device into the VLC/M&C.

Remarks

1. The Matrix-Protection-Switcher device evaluates the switch matrix type from the naming of the input/output parameters used by the device driver of the matrix:

• If the driver defines a parameter output.01 or output.001 the matrix is considered to be distributive.
• If the driver defines a parameter input.01 or input.001 the matrix is considered to be combining.
• If the driver defines a parameter out.01.in.01 the matrix is considered to be crosspoint based.

2. Most matrix drivers use 01,02,...64 as port index, but matrices with more than 99 ports use 3 digit index values.
3. When using a combining matrix, switching the input signals from chain n to the backup chain means that the operational chain has no input signal after this. As the Protection-Switch-N-To-1 device first switches the input signal, then configures the backup equipment and finally switches the backup chain signal on air, there will be some seconds of signal outage between input / output switching.

Variables defined by this device driver