LOOP powered 4 to 20 ma SEVEN SEGMENT INDICATOR

[joshua.svn]

HI,

CAN ANY BODY KINDLY EXPLAIN HOW A LOOP POWERED INDICATOR (4 TO 20MA )

AND THE DISPLAY IS ICL7107

WILL FUNCTION, AND WHAT INTERNAL COMPONENTS AND ALL OTHER STUFF RELATED TO ....

WEB ADDRESS FOR MORE INFORMATION..


http://www.radix.co.in/catalog_data/PLD40_CAT140.pdf


THANKS AND REGARDS
SVN.

 

[panic mode]

4-20mA is calibrated range, with some 3-21mA being full range (including burnout and tolerances).
this means that loop powered device must draw less than 3mA.

since 7-segment display has total of 8 LEDs (segments + DP) and one would likely want at least 3 full digits, we get some 24-27 LEDs.

while there ARE high efficiency displays, with single segment drawing as little as 1mA, combined current draw of the segments is still way above 3mA limit.

note that the ICL71xx is very old product and draws up to 2mA by itself so in this case LED display is out. instead of ICL7107 you can try ICL7106 (which is same thing, just an LCD version). if you really want LEDs, you have to do some serious analysis and careful design.

next, it would be really awesome if you would turn off caps lock. using all caps is bad etiquette meaning you are shouting and nobody likes that...