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SECTION 22.9 GPI CONTROLLERS

GPI, or General Purpose Interface, is long serving analog control signal system based on simple contact closure. GPI inputs and outputs are very common on professional production equipment.

The macro system in NewTek live production devices can take advantage of intermediary devices, such as the eBOX™ network/GPI hardware interface from JLCooper Electronics, to support both GPI signal input and output.

CONFIGURATION

For an external GPI device to communicate with a NewTek live production system, it must be manually defined by text entries in the file named gpi_setup.xml. This file can be located in the directory shown below as appropriate for your product:

 C:\TriCaster\Configuration\

 C:\3Play\Configuration\

The entry for a given GPI control device must contain an IP address and port, password, and custom name, entered as follows:

< device name="name " ip="###.###.###.###" port="##" password=" "/> At the time of writing, the xml ‘element name’ signified above by the placeholder

device should be “jlcooper”, without the quotation marks.

The value for the “name” attribute that follows is a custom name of your choosing.

Hint: Normally, connected GPI devices are identified by unique names in this file; otherwise (if GPI devices share a single name) GPI commands are issued to them simultaneously.

The remaining configuration attributes (“ip”, “port” and “password”) are set at the external hardware device (refer to the vendor’s documentation for details); the corresponding values need only be transferred into the XML configuration file.

A typical entry might look like this:

<jlcooper name="JLCooper1" ip="192.168.128.102" port="23" password=""/>

LISTENING FOR GPI TRIGGERS

Configured and connected GPI interface devices can trigger macros just like a keyboard shortcut, control surface, or MIDI button operation can.

To assign a GPI trigger to a macro, simply click a ‘gesture field’ in the Shortcuts group at the bottom of the Macro Configuration panel, then send the desired external GPI trigger to the system. The ‘listening’ control will recorded the GPI signal, and a suitable shortcut entry will be displayed.

SENDING GPI COMMANDS

A special macro command allows you to send GPI signals to external devices and systems via network-connected GPI interface devices (such as the eBOX™ from JLCooper Electronics).

GPI macro entries are formatted as shown below:

 Delay – the interval, in milliseconds, between the time when the command on the prior line (if any) was issued to the system, and execution of this line.

 Shortcut – Use the entry “gpi” in this field to send a GPI signal.

 Value – The shortcut value is the name of the GPI device (defined earlier in gpi_setup.xml) that you want the signal defined on this line to address.

 Key # (0 – n) – The value you enter in this field identifies a target pin on the external DVI device to receive a signal defined in the following field. The entry should be formatted as “pin#” (e.g., “pin1”, without quotation marks).

 Value # (0 – n) – This value controls the contact closure state (on or off) for the GPI device pin identified by the preceding key. The value can be entered variously as “1” or “0” , “on” or “off”, “true” or “false” (without quotations).

A typical entry might look like the following:

Hint: Multiple GPI pins can be targetted simultaneously by key/value pairs entered on a single line. Alternatively, some GPI devices require a GPI ‘pulse’ of a specified duration. In such a case, you might send an “on” command on one line, followed – after a suitable delay – by an “off” command sent to the same pin.

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