Basler Electric BE1-851 - Manual (Page 148)

The BESTlogic Expression Builder provides a point and click interface that allows the selected input to be
easily connected using a single OR gate, single AND gate, or an AND/OR combination. The usable list of
inputs and outputs in the bottom left of the screen corresponds with the variable lists of Tables 7-1 and
7-2. Currently, the virtual outputs are the only functions that can use the single AND or AND/OR
combination BESTlogic Expression Type.
The top of the screen displays the BESTlogic expression in a text window. Above the text window, the
selected input and the associated ASCII command is displayed.
The Clear button will clear the expression to 0. The Reset button will reset the expression to its original
state when the BESTlogic Expression Builder was first opened. The Cancel button resets the expression
to its original state when the BESTlogic Expression Builder was first opened and returns the user to the
previous screen. The Save button saves the expression shown in the text window and returns the user to
the previous window.
Logic Schemes
A logic scheme is a group of logic variables written in equation form that defines the operation of a multi-
function relay. Each logic scheme is given a unique name of one to eight alphanumeric characters. This
gives you the ability to select a specific scheme and be confident that the selected scheme is in operation.
Six logic schemes, configured for typical protection applications, are stored in nonvolatile memory. Only
one of these logic schemes can be active at a given time. In most applications, preprogrammed logic
schemes eliminate the need for custom programming. Preprogrammed logic schemes may provide more
inputs, outputs, or features than are needed for a particular application. This is because the
preprogrammed schemes are designed for a large number of applications with no special programming
required. Unneeded inputs or outputs may be left open to disable a function, or a function block can be
disabled through operating settings. Unused current sensing inputs should be shorted to minimize noise
pickup.
When a custom logic scheme is required, copying a preprogrammed scheme into the user logic can
reduce programming time. The logic scheme can then be modified to meet the specific application.
User Logic Scheme
Digital, multifunction relays must have a user logic scheme in order to function. All Basler Electric
multifunction relays are delivered with a default user logic loaded into memory. The default user logic
scheme for the BE1-851 is named USER. If the function block configuration and output logic of USER
meets the requirements of your application, then only the operating settings (power system parameters
and threshold settings) need to be adjusted before placing the relay in service.
NOTE
There has been a fundamental improvement to the way the user sets up
BESTlogic in this device. In some prior implementations of BESTlogic, it was
necessary to make a separate setting that determined whether the user’s logic
scheme or one of the preprogrammed logic schemes was to be made active.
This setting was made from the ASCII command interface using the SP-
LOGIC (Set Protection Logic) command. This setting has been eliminated in
relays with firmware version 2.43 and higher.
In the implementation of BESTlogic used in this relay, the logic scheme
defined by the user’s logic settings is always active. If the user wishes to use a
preprogrammed logic scheme, he/she now copies it into his/her user logic
settings. This process is accomplished using BESTCOMS or the ASCII
command interface using the SL-N (Set Logic Name) command in this and
previous BESTlogic implementations
If a different preprogrammed logic scheme is required, it can be easily copied to active logic and used as
is, or customized to your specifications. To accomplish this, communication with the relay must be
established. It is accomplished by connecting a computer to the front or rear RS-232 port.
7-8 BE1-851 BESTlogic™ Programmable Logic 9289900990 Rev R