Filter
Top Products
Advanced Programming
36
ALD-H48 Lighting Controller
Adding Functions to Modules
Commands to The Device
This module supplies a mechanism to allow additional device features to be added to software
using the module. This is the PASSTHRU command, which allows protocol strings to be passed
through the module. The device-specific protocol must be known in order to use this feature.
As an example, suppose that a module for a projector has not implemented the 'white balance
adjustment' feature. The command that the projector protocol requires is 03H, 10H, 05H, 14H,
followed by a checksum. The documentation for the PASSTHRU command specifies that the
module will automatically generate the checksum. In this case, the following string should be sent
from the UI code to implement 'white balance adjustment'.
send_command vdvDevice, "'PASSTHRU-',$03,$10,$05,$14"
The reason to use PASSTHRU instead of sending a protocol string directly to the device port is that
the device may require command queuing, calculation of checksums, or other internal processing,
which would not be done if the string was sent directly. Because of this, it is best to filter all
communication TO the device through the module. (The module documentation will indicate any
processing that will be automatically done to the PASSTHRU string like checksum calculation.)