PCC-IV Instruction Manual (rev. 0.1)
Page 1-4
Section 1 - Product Overview
Blockware Concepts
The PCC-IV makes use of Blockware (aka Function Blocks) which makes control strategy configuration easy. In
Section 5
, we will discuss Blockware and configuration in greater detail, but the basic elements that make up
Blockware are as follows:
Blocks
The PCC IV memory is made up of blocks. Each block is a container into which a Blockware Function is placed.
Think of a b
lock as a “cell” in an Excel spreadsheet, you put a formula or a function into a cell, and the formula uses
the values from other cells as inputs for the formulas. The controller includes sufficient memory to handle 256
blocks.
Library of Functions
The PCC-IV has an extensive library of Functions to handle any type of control task. These Functions are identified
and described in detail in
Section 6
of this manual. The library includes Functions for the conversion of inputs to
engineering values, mathematical operations, logical operations, timing operations, the traditional PID algorithm,
and other types of special
PID
Functions. Additional special Functions such as “Learn”, “Boiler Efficiency”, etc. are
included and are described in
Section 6
.
Any-Function-Any-Block
Each block is assigned a Function-type during configuration. Any Function-type can be used in any block number.
The block number only determines the order in which the blocks are calculated. In the example below at left, Block
number 22 is not being used, so it has the default
NOP
, or “
N
o
OP
eration” Function in it. At right, Block 22 was
changed from a
NOP
to a
HIALM
(high alarm) Function type.
Reusable Functions
Almost all PCC IV Function-types can be used as many times as required, within the 256-block limit. There are
some Functions that are directly linked to the hardware that can only be used as many times as there is mating
hardware. For example, only one
PANEL
Function (Front Panel Display Interface) can be used because there is
only one front panel. While those related to
PID
Functions, curve fitting Functions, etc. can be used as many times
as is deemed necessary for the application.
Softwiring
Most Function-types, like
HIALM,
need information from other sources (i.e., blocks) to calculate a result. Softwiring
is the term used to describe how the blocks are interconnected within the software. Softwiring allows the input of a
block to monitor the output of any other block. At right below, the PV (Process Variable) input of Block 22 (
HIALM
)
is monitoring the output of Block 20 (
AIN
), via a softwiring connection.
