Omron NX-SL series User Manual

3 Safety Standard Function Blocks
3 - 8
NX-series Safety Control Unit Instructions Reference Manual (Z931)
 Operation as an Up Counter
When reset signal RESET changes to TRUE, counter value CV changes to 0 and up-counter output
QU changes to FALSE.
When up-counter input signal CU changes to TRUE, CV is incremented. When the value of CV
reaches the value of PV or higher, the value of QU changes to TRUE.
After the value of CV reaches the value of PV or higher, the value of CV does not change even if the
value of CU changes to TRUE.
 Operation as a Down Counter
When load signal LOAD changes to TRUE, counter value CV changes to the value of preset value
PV and down-counter output QD changes to FALSE.
When down-counter input signal CD changes to TRUE, CV is decremented. When the value of CV
reaches 0 or less, the value of QD changes to TRUE.
After the value of CV reaches 0 or less, CV does not change even if CD changes to TRUE.
 Common Operation for Up and Down Counters
CU and CD are ignored while LOAD or RESET is TRUE. CV is not incremented or decremented.
If both CU and CD change to TRUE at the same time, CV will not change.
If RESET and LOAD are both TRUE, RESET has priority and the value of CV changes to 0.
If RESET changes to TRUE, CV changes to 0, and so QD changes to TRUE.
If LOAD changes to TRUE, the value of CV changes to PV, and so QU changes to TRUE.
The following table shows the relationship between RESET, LOAD, CV, QU, and QD. This assumes
that the value of PV is larger than 0.
RESET Load CV QU QD Operation
FALSE FALSE 0 or lower FALSE TRUE Only an up counter operation is
performed.
CV is incremented when CU
changes to TRUE.
It is not decremented when CD
changes to TRUE.
Between 0
and PV
FALSE FALSE Both up and down counter opera-
tion is performed.
CV is incremented when CU
changes to TRUE and decre-
mented when CD changes to
TRUE.
PV or higher TRUE FALSE Only down counter operation is
performed.
CV is decremented when CD
changes to TRUE.
It is not incremented when CU
changes to TRUE.
TRUE FALSE 0 FALSE TRUE The up counter is reset.
The value of CV is set to 0.
FALSE TRUE PV TRUE FALSE The down counter is reset.
The value of CV is set to PV.
TRUE TRUE 0 FALSE TRUE The up counter is reset. Reset
takes priority over Load.
The value of CV is set to 0.

Omron NX-SL series Specifications

General

Brand	Omron
Model	NX-SL series
Category	Control Unit
Language	English

Summary

Introduction to Instructions for Safety Control Units and Interpreting Instruction Descriptions

Types of Instructions

Describes the three types of instructions used with Safety Control Units.

Interpreting Instruction Descriptions

Explains the notation used to describe instructions.

Standard Functions

Execution Control Instructions

Details instructions for controlling program execution flow.

Data Type Conversion Instructions

Explains instructions for converting data types between different formats.

Boolean Operation Instructions

Describes instructions for performing logical Boolean operations.

Math Instructions

Details instructions for arithmetic operations on integers and durations.

Comparison Instructions

Instructions for comparing values of variables.

Selection Instructions

Instructions for selecting values based on conditions.

Safety Standard Function Blocks

Safety Standard Function Block Instructions

Lists and describes safety standard function block instructions.

SF_CTD

Decrements the counter value when the counter input signal is received.

SF_CTU

Increments the counter value when the counter input signal is received.

SF_CTUD

Creates an up-down counter operating on up and down counter inputs.

SF_F_TRIG

Outputs TRUE for one task period when the input signal changes to FALSE.

SF_R_TRIG

Outputs TRUE for one task period when the input signal changes to TRUE.

SF_RS

Retains the value of a SAFEBOOL variable, giving priority to Reset.

SF_SR

Retains the value of a SAFEBOOL variable, giving priority to Set.

SF_TOF

Outputs FALSE when the set time elapses after the timer starts.

SF_TON

Outputs TRUE when the set time elapses after the timer starts.

SF_TP

Outputs TRUE during the set time after the timer starts.

Safety Function Blocks

General Rules for Safety Function Blocks

Provides general rules for safety function blocks, including rules specific to FBs.

Safety Function Block Instructions

Lists and describes various safety function blocks.

SF_Antivalent

Monitors discrepancy time for two antivalent SAFEBOOL inputs.

SF_EDM

Controls a safety output and monitors actuator control.

SF_EmergencyStop

Monitors the input from an emergency stop button.

SF_EnableSwitch

Supports stopping a safety function using an enable switch.

SF_Equivalent

Monitors discrepancy time for two equivalent SAFEBOOL inputs.

SF_ESPE

Monitors electro-sensitive protective equipment (ESPE).

SF_GuardLocking

Controls entry to hazardous areas with a four-state interlock guard.

SF_GuardMonitoring

Monitors safety guards and opens/closes them.

SF_ModeSelector

Selects system operation mode (automatic, manual, etc.).

SF_MutingPar

Performs parallel muting with four muting sensors.

SF_MutingPar_2Sensor

Performs parallel muting with two muting sensors.

SF_MutingSeq

Performs sequential muting with four muting sensors.

SF_OutControl

Controls a safety output with control and safety signals.

SF_SafetyRequest

Makes requests for safe state and monitors actuator safety state.

SF_TestableSafetySensor

Tests functionality with external test function of ESPE sensors.

SF_TwoHandControlTypeII

Provides type II, two-hand control function per ISO 13851.

SF_TwoHandControlTypeIII

Provides type III, two-hand control function per ISO 13851.

Index