PLC Programming Fundamentals – OTE Instruction

Introduction

The OTE, also known as Output Energize, instruction will energize a single bit of data if the input leading to it is true. It’s a fundamental instruction used in Programmable Logic Controllers (PLCs). This instruction will be found on the right side within a ladder logic structure and turn a bit to a HIGH state if the preceding instructions evaluate to true. If the same instructions evaluate to false, the OTE instruction will set the specified bit to a LOW state.

Example & Usage of OTE

Here’s a real-world scenario of an OTE instruction:

1. A Micrologix 1100 Allen Bradley PLC is used to control a process.
2. A motor contactor is connected to Output 0 (O:o/o of the PLC).
3. A normally open push button (“System Start”) is connected to Input 0 (I:0/0 of the PLC).
4. An operator presses the start button.
5. The XIC instruction is tied to I:0/0.
6. The OTE instruction is tied to O:0/o.
7. The OTE instruction energizes the output (O:0/0) while the XIC is TRUE.
8. The OTE instruction de-energizes the output (O:0/0) while the XIC is FALSE.

Programming example in RSLogix 500:

Outcome:
The OTE instruction will energize the output of the PLC which will allow the motor tied to the starter to run.

Data Types Allowed for OTE

The OTE instruction will work with the following data types within the RSLogix 500 environment:

• Boolean – The OTE may only evaluate TRUE/FALSE or 1/0 or HIGH/LOW.

Important Notes

• Note 1 – The OTE instruction was initially used to set the status of miscellaneous outputs landed on the PLC. However, it may be used on any boolean within the program. In other words, it can energize or de-energize any boolean within the program. Through this property, programmers can utilize the OTE instruction for a wide range of applications.