Preferred Instruments PCC-IV, Instruction Manual

Page: 89 / 135

PCC-IV Instruction Manual (Rev. 0.1) Page 6-4 Section 6
– Blockware Functions
Technical Reference
F0 [A0] Analog Constant, 0.00%
Function A0 provides a constant Output of 0.00%.
No inputs or parameters are required for
A0 .
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NAME: A0 SINGLE USE FUNCTION: N OUTPUT TYPE: A
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No Inputs and No Parameters
F1 [A100] Analog Constant, 100.00%
Function A100 provides a constant Output of 100.00%.
Analog 100.00% is useful as a dummy input to many other functions:
ASW , AB/C ,
…. No inputs or parameters are
required for A100 .
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NAME: A100 SINGLE USE FUNCTION: N OUTPUT TYPE: A
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No Inputs and No Parameters
F2 [AIN] Analog Input
Function AIN is the blockware interface to the PCC-IV Analog Inputs A/D converter hardware. AIN retrieves the
0.000 - 5.100 Vdc signal from the selected field terminals, applies a digital low pass filter, scales the voltage to a 0-
100.00% Block Output, and optionally takes the square root. A jumper selectable 250 ohm, 0.1% resistor on the
circuit board is used to convert a 4-20 mA Input to 1-5 Vdc Input. A hardware based low pass filter (-3 dB @ 0.6
Hz, -63 dB @ 60 Hz) is included for each analog Input for noise reduction, and high frequency aliasing prevention.
The AIN function interfaces to Analog Inputs on the CPU board and on option boards. Parameter 1 specifies the
board location, the CPU board = board 0. Parameter 2 selects a specific Input on the specified board.
Any portion of the 0 - 5.100 Vdc Input range (0.5 Vdc min. span) may be selected and scaled to the 0-100.00%
Block Output using parameters 3 & 4. Voltages outside the configured 0-100.00% range produce proportional Block
Outputs, within the limitations of 0-5.100 Vdc measurement range, and +/- 327% Block Output range. Parameters
3 & 4 may be configured for reverse Inputs (0% = 5 Vdc, 100% = 1 Vdc for 20-4 mA transmitters).
Scaling Example: Parameter 3 (0%) = 1.000 Vdc, Parameter 4 (100%) = 5.000 Vdc. Outputs for other voltages:
0.000 Vdc = -25%, 1.000 Vdc (or 4 mA) = 0 %, 4.000 Vdc (or 20 mA) = 75.00%, 5.100 Vdc in = 102.50%
The square root option is scaled for 0-100% Input = 0-100% Output, that is:
Block Output = 10 * [sq. root (Input).]
Square Root Example:
100% Input = 100% Output, 49% Input = 70% Output, 4% Input = 20% Output. Negative Inputs yield a 0% Output.
The Low Flow Cutoff parameter forces the Block Output to 0.00% if the Block Output would be less than (Parameter
7). This feature is bypassed if the Cutout is 0.0%.