PLC Simulator
Pro
5 min

CCST 01 — XIC/XIO Basic Contacts

ccstladdercontactsxicxio

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CCST 01 — XIC/XIO Basic Contacts scenario preview

Briefing

Write a rung that energises OUTPUT_1 when SENSOR_A is TRUE and SENSOR_B is FALSE. Tests your understanding of Examine-If-Closed (XIC) and Examine-If-Open (XIO) contacts.

Objectives

  • Use an XIC contact for SENSOR_A
  • Use an XIO contact for SENSOR_B
  • Energise OUTPUT_1 when both conditions are met

Hints

  • XIC energises when the bit is 1 (TRUE)
  • XIO energises when the bit is 0 (FALSE) — insert a NOT in IEC
  • OUTPUT_1 := SENSOR_A AND NOT SENSOR_B

I/O Table

Inputs

SENSOR_A

Sensor A

BOOL · %I0.0

SENSOR_B

Sensor B

BOOL · %I0.1

Outputs

OUTPUT_1

Output 1

BOOL · %Q0.0

Your program will be tested against:

All test cases run automatically when you submit. Assertions are hidden until you pass.

  1. #1OUTPUT off when both inputs false

    OUTPUT off when both inputs false

  2. #2OUTPUT on when A=T, B=F

    OUTPUT on when A=T, B=F

  3. #3OUTPUT off when B is also true

    OUTPUT off when B is also true

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Job-readiness and assessment field guide

CCST 001 XIC and XIO contact practice: readiness checklist

Direct answer

The candidate can build a truth table, predict rung continuity for both tag states and explain the complete field-to-tag-to-output path.

Written for beginning controls candidates learning how examined-on and examined-off contacts evaluate a Boolean tag without confusing symbols with physical contact construction.

a controls technician completing an evidence-led practical assessment on a generic PLC, alarm, motor and instrumentation bench while studying XIC and XIO Boolean evaluation, field-state meaning and scan-by-scan evidence
System map / 02

NODE 01observable

Role scope

Physical condition, input electrical state, controller Boolean tag, XIC truth, XIO truth, rung result, final output and scan timing.

NODE 02observable

Skills map

Field contact through input channel and image into Boolean evaluation, branch result, output command and independent physical response.

NODE 03observable

Core exercise

False and true states tested from a clean scan with the written truth table matching observed rung and output behavior.

NODE 04observable

Stretch case

Normally open versus normally closed device, inverted meaning, alias mismatch, forced value, multiple writers, startup state and fast transitions.

NODE 05observable

Troubleshooting

A field, electrical, input-image, tag, instruction-truth, rung, final-writer or output-response mismatch.

NODE 06observable

Portfolio evidence

The behavior recreated with exact target-platform instruction help, I/O configuration and supervised physical checks.

Answer surface / 07

Does XIO mean a normally closed field contact?

No. XIO describes how the instruction evaluates its Boolean operand. The physical device contact arrangement and the tag’s process meaning are separate decisions.

How do I remember XIC versus XIO?

Use a two-row truth table: XIC is true when its Boolean operand is true; XIO is true when the operand is false. Then map that operand back to the real field condition.