VVP10 HART
HART
®
VALVE POSITIONER
INSTALLATION, OPERATION, CONFIGURATION AND MAINTENANCE MANUAL
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Rate Open/Close
It sets the opening and closing time of the actuator to slow down the system.
The open rate will be given by R
open
= 100% / t
open
, provided that t
open
is higher than the value found in the Auto
Calibration procedure (in seconds).
The closing rate will be given by R
close
= 100% / t
close
, provided that t
close
is higher than the value found in the Auto
Calibration procedure (in seconds).
WARNING
These times will be automatically changed to the maximum system performance (lowest value possible)
when the Auto Calibration or Opening/Closing Test procedures are performed.
CHARACTERIZATION CURVES
This directory (
Specific/Characterization
) allows user to configure the Setpoint according to a pre-established system
flow characterization function or following a specific table of up to 16 points. The pre-established characterization
functions are described below.
Linear
This function characterizes the output directly proportional to the Setpoint input signal (either by the input current or
local mode).
Equal Percentage (EQ)
This function characterizes the output according to a percentage increment in the flow over its previous value. This
percentage can be 25%, 33% or 50%, which causes a logarithmic curve as shown in the following figure.
Quick Open (QO)
This function characterizes the output according to a high increase in the flow, also in percentage (25%, 33% or 50%)
on a small variation in the input signal, which causes a logarithmic curve as shown in the following figure.
Figure 3.11 – Linear, equal percentage and quick opening functions for Setpoint characterization (respectively).
User Table
Used in measurements that require custom output.
VVP10 HART has a user table with 16 points with input
and output as a percentage (depending on the input
signal).
The user must configure at least two points in the table.
The points will define the characterization curve to be
used for the calculation of the Setpoint that will be sent
to the PID control.
It is recommended to select equally distributed dots over
the desired band or over a part of the band where better
precision is required. The table should be monotonically
increasing, ie all points in the growing order of x, as in
the example in figure 3.12.
Figure 3.12 – Setpoint characterization user table.
