Before connecting a potentiometer to an analog input, the potentiometer must be biased with 5 volts. This is done by simply connecting 5 volts to one side of the pot and ground to the other. The wiper (center connection) of the pot is then connected to one of the analog inputs. To read the pot position an RDx command is sent to the ADR Interface . The interface will respond with position information represented by a digital number depending on the resolution of the analog input.

000 to 255 for 8-bit inputs ( ADR101)

0000 to 1023 for 10-bit inputs ( ADR2100)

0000 to 4095 for 12-bit inputs ( ADR2000A,ADR2000B,ADR2010)

00000 to 65535 for 16-bit inputs ( ADR7700 )

This sample BASIC program below reads the position of the two pots using an ADR101 and continually updates their position on the screen.

10 OPEN "COM1:9600,N,8,1,CS,DS,RS" AS#1
20 CLS
30 LOCATE 1,1
40 PRINT#1, "RD0"
50 INPUT#1, POT1
60 PRINT#1, "RD1"
70 INPUT#1, POT2
80 POT1=(POT1/255)*100 :PRINT "POT#1 IS AT"POT1, "PERCENT"
90 POT2=(POT2/255)*100 :PRINT "POT#2 IS AT"POT2, "PERCENT"
100 GOTO 40        

 Back to Applications Page

NEWS         PRODUCTS         PROGRAMMING          APPLICATIONS          CUSTOM DESIGN          ORDERING          HOME

TestPoint is a trademark of Capital Equipment Corp.   
LabVIEW is a trademark of National Instruments.
Visual BASIC is a trademark of Microsoft Corporation

Copyright © 1999 ONTRAK CONTROL SYSTEMS 764 Notre Dame Ave, Unit #1 , Sudbury, Ontario, CANADA P3A 2T2  
"Quality serial Data Acquisition Interfaces"           PH. (705) 671-2652 FAX (705) 671-6127