Application; Technical Characteristics; Functions: Analogue Calculator; Sample-Hold - PR electronics 2289 User Manual

SIGNAL CALCULATOR 2289
• Two analogue inputs
• Multiple functions
• Front-programmable
• 3-digit LED display
• Version with a Pt100 input
• Analogue output

APPLICATION:

Operates as a PID controller with an analogue or a Pt100 input, a manual /
automatic controller, an analogue calculator with a scale function on both inputs,
a sample-hold transmitter, a peak-hold transmitter, a delay transmitter, a signal
limiter, averaging of noisy signals, monitoring of a signal's slope, or an analogue
•
multiplexer. The 2289 Signal Calculator will meet the demands of any process
engineer with an unexpected or special signal processing assignment at hand.

TECHNICAL CHARACTERISTICS:

The unit is built around a microprocessor core with an efficient program operation.
The basic calibration data and the present set-up are saved in an EEPROM
thereby avoiding the loss or change of data at power off. The user interface
consists of a 3-digit dis play and 3 front function keys. The input and output values,
function, and all parameter selections are entered by means of the user interface.
Both the input signals and the output signal can be inverted.
FUNCTIONS:
ANALOGUE CALCULATOR:
Contains the following calculation functions: addition, sub traction, maximum /
minimum selection, multi plication, division, raising to a power and root extraction.
At raising to a power and root extraction, any of the analogue inputs can be
selected. By means of the scale function the calculation functions can be
executed on differently scaled input signals.

SAMPLE-HOLD:

Activation of the digital input (hold) will set the output value to the present
input value and will hold this value for as long as the digital input is active. At a
deactivated digital input the output value will track the input value.
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PEAK-HOLD:

At a deactivated digital input the output value is the greatest input value
registered since the last reset. Activation of the digital input will set the output
value at the present input value (reset).

DELAY:

The delay function transfers the input value to the output according to an
exponential curve (R/C delay), where the time constant of the R/C delay can be
entered.

PID CONTROLLER:

Features the following regulation parameters: XP (proportio nal band), TI
(integrating time), and TD (differentiating time). The units are selected as XP %,
TI s, and TD s. By selecting TI and TD as 0, the function will be a pure proportional
controller. The regulation can be either direct or inverted. The setpoint can be
selected as an internal or external current / voltage signal.

MANUAL / AUTOMATIC CONTROLLER:

The digital input is used to change between the manual and automatic mode. In
the auto matic mode the analogue output follows input A. When changing to the
manual mode the analogue output is fixed and can now be activated up or down
manually. The output holds the manual setting for an unlimited period.

SIGNAL LIMITER:

By the signal limiting function the output follows the input values linearly in the range
between the min. and max. settings. At input signals outside the min. and max.
settings, the output is fixed on either the min. or the max. value. The min. or the
max. value can be set externally by means of the other analogue input.

AVERAGING TRANSMITTER:

The averaging function calculates an accurate average value of the input values
over a set period. Once this period has expired the output will be updated by the
average value. This means that the ouput will typically make a jump at each update.
A stack function can be selected to increase the updates of the output and to
decrease any jumps while still keeping the set averaging period.

SLOPE TRANSMITTER (DI/DT FUNCTION):

The dI/dt function converts the slope of the input over a set period to an analogue
output signal. The min. and max. slope to be converted are entered in % of the
input span. The slope can be selected as either positive or negative. By means
of a pressure transmitter the dI/dt function is suitable for for instance leak
monitoring or flow measurement of substances with a high viscosity grade.
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