Set-dominant bistable (sr), C.1.13 set-dominant bistable (sr) – Nematron Pointe Controller User Manual

Page 348

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Appendix C: Ladder Diagram Block Reference

Pointe Controller User Guide

346

Configuration Reference

The parameters of this block are described in the following table:

Param

Name

Config

Var Type

Description

EN

Enable

no

-

The state of the rung (off/on)
received from the left.

ENO

Enable
Out

no

-

The state of the rung (off/on)
passed to the right.

CLK

Clock

req

%IX

%MX

%QX

T_DONE

The input value.

Q

Output

req

%IX

%MX

%QX

The output value that is triggered
when the input value transitions
from 0 to 1.

C.1.13 Set-Dominant Bistable (SR)

When used in a Ladder Diagram, the SR block switches an output bit between 0
and 1 depending on the values of two input bits. The block is “set-dominant,
meaning that a decision to set the output bit to 1 will override a decision to reset
the output bit to 0.

Select the

tool (from the

Relays and Coils

toolbar) and click on a ladder rung

to insert the following block:

Once the block is inserted, you can double-click on it to

configure

it.

Functional Description

This block always passes the Enable input state (EN) through to the Enable Out
output state (ENO) without change; when EN becomes on, ENO is turned on, and
when EN becomes off, ENO is turned off.

When EN becomes on, the block function is executed: a new value for the Output
(Q) is determined based on the Set and Reset inputs (S1 and R), as well as the
existing value of Q. If S1 is true or 1, then Q is set to 1. If R is true or 1, then Q is
reset to 0. (However, the block is set-dominant, so S1 will override R.) If both S1
and R are false or 0, then Q is left at its existing value regardless of what it is.

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