Carlo Gavazzi UDM35/40 & USC - Manual (Page 11)

UDM 35/40 PANEL METER USER MANUAL
10
Linearization
Introduction
When is displayed, a signal from a non-linear transducer-sensor
may be modified by setting the input (in. 01 – in. 16) and output (ou. 01 –
ou.16) linearization points so that the accuracy of the displayed value is
maximized. This programming step is available when using the UDM40
and LSX/HSX input modules only. On the illustration below, the nominal
output characteristics of an analog inductive proximity sensor is 4-20mA.
Note the non-linear curve. The nominal characteristics need to be divided
into a number of segments. In this example, we can divide the curve into
9 segments (9 segments + 1) corresponding to the vertical axis. The
menu must be activated and the number of linearization points
set (10 in this example). Then the input/output coordinates must be
determined and entered into the program. In this example, going from
right to left on drawing, Input 1 (shown on drawing as “1.0”; displayed as
“in.01”) = 4. Output 1 (displayed as “ou.01) = 1.0. Likewise “in.02” (shown
on drawing as 0.9) =4.5, ou.02=0.9……Fast-forward to “in.09”=12,
ou.09=0.2, and “in.10”=20, “ou.10=0.1.
It is important to note that the first and last linearization points must
correspond to those points defined in the scale menu . In this
example: “in.01”= LoE, “ou.01”=Lo.d, “in.10”=HiE, “ou.10”=Hi.d.
Inputs are noted on the “X” axis and the analog current values along the
“Y” axis. Input 1.0 has a value of 4. The second input, 0.9, has a value of
4.5, etc.