Hach 4-20 mA Manual Del Usuario página 10

Option Description
SET FUNCTION Select a function. Further options will vary depending on
which function is chosen. LINEAR CONTROL—Signal is
linearly dependent on the process value. PID
CONTROL—Signal works as a PID (Proportional,
Integral, Derivative) controller. LOGARITHMIC—Signal
is represented logarithmically within the process variable
range. BILINEAR—Signal is represented as two linear
segments within the process variable range.
SET TRANSFER If TRANSFER is or will be selected as the ERROR
HOLD MODE, select SET TRANSFER and enter the
transfer value. Range: 3.0 to 23.0 mA (default = 4.000).
Refer to Set the error hold mode
SET FILTER Enter the filter value. This is a time-average filter value
of 0 to 120 seconds (default = 0).
SCALE 0mA/4mA Select the scale (0–20 mA or 4–20 mA).
4–20 mA activation options
1. Select SETUP SYSTEM>SETUP OUTPUTS>4–20mA SETUP.
2. Select the applicable OUTPUT.
3. Select SET FUNCTION>LINEAR CONTROL and then select the
applicable options in the ACTIVATION menu.
Option Description
SET LOW VALUE Sets the low endpoint of the process variable range.
SET HIGH VALUE Sets the high endpoint (upper value) of the process
variable range.
10 English
4. Select SET FUNCTION>PID CONTROL and then select the
applicable options in the ACTIVATION menu.
Option
SET MODE
PHASE
on page 11.
SET SETPOINT Sets the value for a control point in the process.
PROP BAND
INTEGRAL
DERIVATIVE
TRANSIT TIME
Description
AUTO—the signal is automatically controlled by the
algorithm when the analyzer uses proportional, integral
and derivative inputs.
MANUAL—the signal is controlled by the user. To change
the signal manually, change the % value in MANUAL
OUTPUT.
Selects the signal result when process changes occur.
DIRECT—signal increases as the process increases.
REVERSE—signal increases as the process decreases.
Sets the value for the difference between the measured
signal and the necessary setpoint.
Sets the period of time from the reagent injection point to
the contact with the measuring device.
Sets a value that adjusts for vacillation of the process. The
majority of applications can be controlled without the use
of the derivative setting.
Sets the value to stop the PID control for a selected period
of time when the sample moves from the control pump to
the measurement sensor.