Boolean Engineering Pty. Ltd.

Audiophile and Home Theatre Electronics Technology Design


LTD 4 - 20
Large Trending Display of 4 - 20 ma Data Stream


WHAT IS THE EASYdisplay LTD 4 - 20


The EASYdisplay device is a 1 metre long strip of 30 individually addressable, full colour LEDs that display the data from a 4 -20 ma current loop in a large format, trending data display mode.

Each unit has a solid state relay alarm ouput that is triggered by user set PCB links for high and/or low set points, and device operation and status is echoed via a USB port for remote monitoring and data logging.

If the USB has been connectioned to a RS232 terminal handler like CoolTerm, then the following status reports will be displayed:

Confirmation that the LTD 4 - 20 is on and the serial connection is operational. Confirm Model: e.g. LTD 4 - 20 is a 1 metre long display strip with 30 LED density etc.

Test LEDs for operation at the used colours Red, Green, Blue, White and blank. Read the High and Low user selected set point links

AN59 - EASYdisplay: Standard Operation Mode


Process and Idustrial control systems generate Trending data, usually displayed by digital meters. The EASYdisplay generates large format (1 metre), intelligent data display(colour and motion) to assess these process variables which can be loggeg via the USB link.

Process systems in large, noisy and poorly lit machine halls can now be monitored from afar and with greater intelligence than standard digital meters and status lights.


As each value of the 4 - 20 ma loop current is read it is reported for logging and displayed as follows:
RED for values above the High set point.
BLUE for values below the Low set point.
GREEN for values between the High and Low set points.
WHITE for user selected set points.

Loop integrity is continually tested, and the display will whiteout if the current is less than 4 ma. If High or Low set points are detected, the alarm relay is activatd and the LEDs in that zone flash a warning.

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