Basler BE1-CDS240, Instruction Manual

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9365200990 Rev F BE1-CDS240 BESTlogic Programmable Logic 7-1
SECTION 7

BESTLOGIC PROGRAMMABLE
LOGIC
INTRODUCTION
Multifunction relays such as the BE1-CDS240 Current Differential System are similar in nature to a panel
of single-function protective relays. Both must be wired together with ancillary devices to operate as a
complete protection and control system. In the single-function static and electromechanical environment,
elementary diagrams and wiring diagrams provide direction for wiring protective elements, switches,
meters, and indicator lights into a unique protection and control system. In the digital, multifunction
environment, the process of wiring individual protection or control elements is replaced with the entry of
logic settings. The process of creating a logic scheme is the digital equivalent of wiring a panel. It
integrates the multifunction protection, control, and input/output elements into a unique protection and
control system.
BESTlogic is a programming method used for managing the input, output, protection, control, monitoring,
and reporting capabilities of Basler Electric's digital, multifunction, protective relay systems. Each relay
system has multiple, self-contained function blocks that have all of the inputs and outputs of its discrete
component counterpart. Each independent function block interacts with control inputs, virtual outputs, and
hardware outputs based on logic variables defined in equation form with BESTlogic. BESTlogic equations
entered and saved in the relay system's nonvolatile memory integrate (electronically wire) the selected or
enabled protection and control blocks with control inputs, virtual outputs, and hardware outputs. A group
of logic equations defining the function of the multifunction relay is called a logic scheme.
One preprogrammed relay logic scheme is stored (embedded) in the relays memory and several others
are available in the logic library of BESTCOMS, Basler Electric's Windows based graphical user interface
program.
Each scheme is configured for a typical protection application and virtually eliminates the need
for “start-from-scratch” programming. Any of the preprogrammed schemes can be copied and saved as
the active logic. Preprogrammed logic schemes can also be copied and then customized to suit your
application. Detailed information about preprogrammed logic schemes is provided later in this section.
BESTlogic is not used to define the operating settings (pickup thresholds and time delays) of the
individual protection and control functions. Operating settings and logic settings are interdependent but
separately programmed functions. Changing logic settings is similar to rewiring a panel and is separate
and distinct from making the operating settings that control the pickup thresholds and time delays of a
relay. Detailed information about operating settings is provided in Section 4,
Protection and Control .
WORKING WITH PROGRAMMABLE LOGIC
BESTlogic uses two types of logic settings: output logic settings and function logic block settings. These
two types of settings are discussed in the following paragraphs. Output logic settings are entered in
equation form and control the hardware outputs of the relay. BESTlogic function blocks are illustrated in
Figures 7-1 through 7-5 and are discussed in the following paragraphs.
Names assigned to inputs, outputs, timers, and protection and control elements represent the logic
variables in the equations. Table 7-1 lists the logic variable names and descriptions.