Siemens SIMATIC S7-1500 PLCs 350

absolute encoder

A device that communicates the current position of a machine axis.

AC

Alternating Current. Current that periodically reverses direction.

analog I/O channels

I/O channels that connect to analog I/O devices. Analog channels use varying voltage or current signals.

analog input device

A device that provides a variable current or voltage, such as 4 to 20 milliamps or 0 to 10 volts, representing a condition in a machine or process. An analog input device provides its signal to an analog input signal channel.

analog output device

A device that is provided a variable current or voltage, such as 4 to 20 milliamps or 0 to 10 volts, representing a condition in a machine or process. An analog output device receives its signal from an analog output signal channel.

bit memory

Part of the global memory of a PLC that incudes binary bits that are available for use by any program block.

code work memory

A section of the work memory that contains parts of the PLC program code.

communication modules

Modules that allow a PLC to communication with other devices through one or more communication ports on the module.

CPU

Central Processing Unit. The brains of the PLC. The CPU stores and scans the user program and stores data needed by the user program and other devices and systems.

data blocks

DBs. Each DB is an organized set of data in a Siemens PLC program that is used by one or more program blocks. An instance DB stores data use by one program block. A global data block contains data that is available to any program block.

data work memory

A section of the work memory that contains parts of the data blocks and technology objects.

DB

Data Block. An organized set of data in a Siemens PLC program that is used by one or more program blocks. An instance DB stores data use by one program block. A global data block contains data that is available to any program block.

DC

Direct Current. Current that flows in one direction.

DIN rail

A 35 millimeter mounting rail for control components and related devices.

fieldbus

An industrial network used for distributed control communication.

firewall

A software or hardware security barrier designed to limit access to a system to authorized personnel or systems.

GB

Gigabyte. Approximately 1 billion bytes. Each byte is 8 consecutive bits.

global memory

Memory areas such as image tables and bit memory that are accessible to all program blocks in the user program.

HMI

Human machine interface. A device or system that displays machine or process information and provides a means for entering control information.

human machine interface

HMI. A device or system that displays machine or process information and provides a means for entering control information.

I/O

Input/Output. Refers to a device, channel, or module involved with PLC inputs and/or output

IEC 61131

A standard of the International Electrotechical Commission that provides common approaches and concepts for PLCs.

image tables

Tables in a PLC CPU memory that store the most recent input and output status conditions. A binary 1 represents an on condition and a binary 0 represents and off condition.

incremental encoder

A device that provides pulses to indicate changes in position.

industrial ethernet

A type of Ethernet local area network that is widely used for computer and control system communication in factories and other industrial environments.

input/output

I/O. Refers to a device, channel, or module involved with PLC inputs and/or outputs.

kbps

Kilobits per second. 1 kbps is a data rate of 1000 bits per second.

LED

Light emitting diode. An indicator light made from semiconductor material.

load memory

Non-volatile storage for the user program, program data, and configuration information.

local memory

Temporary memory used during the processing of a code block.

modbus RTU

Modbus remote terminal unit. A serial communication protocol used to connect a master device, often a PLC or industrial computer, to slave devices. The master device controls the communication of slave devices.

non-volatile memory

Used to describe a type of memory that does not require continual application of power to prevent data loss.

PID Control

Proportional-integral-derivative control. One of the most common types of process control. PID control adjusts system outputs by reacting to three values, one that is proportional to an error, one that represents the error over time, and one that represents the rate of change of the error.

PROFIBUS DP

PROFIBUS DP is an open standard fieldbus of PROFIBUS & PROFINET International (PI) that is widely used for master-slave control communications in factory automation.

PROFINET

The open Industrial Ethernet standard of PROFIBUS & PROFINET International (PI), and the leading Industrial Ethernet standard world-wide.

PROFINET IO

The most widely-used form of PROFINET. PROFINET IO extends the benefits of standardized, Ethernet communication to distributed field devices.

PROFINET IRT

PROFINET isochronous real-time. The highest of three simultaneous performance levels of PROFINET IO communication. PROFINET IRT communication is designed to handle the most time-sensitive motion control applications.

program block

A grouping of PLC instructions. A Siemens PLC can have three types of program blocks: organization blocks (OBs), function blocks (FBs), and functions (FCs).

proportional-integral-derivative control.

PID control. One of the most common types of process control. PID control adjusts system outputs by reacting to three values, one that is proportional to an error, one that represents the error over time, and one that represents the rate of change of the error.

quadrature encoder

A two-channel incremental encoder. By comparing the phasing of the pulses received from both channels, a controller can determine the direction of motion.

resistance temperature device

RTD. A temperature sensor made from a metal such as platinum, nickel, or copper that varies in resistance in a predictable manner as temperature varies.

retentive memory

Non-volatile storage for a limited quantity of work memory values during power loss.

RTD

Resistance Temperature Device. A temperature sensor made from a metal such as platinum, nickel, or copper that varies in resistance in a predictable manner as temperature varies.

run mode

One of three modes of operation for an S7-1500 PLC. In the RUN mode, the CPU executes the PLC scan repeatedly.

scan

A repetitive process performed by a PLC CPU that includes updating input statuses, executing the user program, updating outputs, and other important tasks.

signal module

Also called an I/O module. A module that connects a PLC to input and/or output devices.

STARTUP Mode

One of three modes of operation for an S7-1500 PLC. In the STARTUP mode, the CPU executes any startup logic, if present.

STEP 7 Professional (TIA Portal)

Engineering software used for the configuration and programming of SIMATIC S7-300, S7-400, S7-1200, and S7-1500 PLCs and related devices

STOP Mode

One of three modes of operation for an S7-1500 PLC. In the STOP mode, the CPU is not executing the user program.

thermocouple

A temperature sensor made from two dissimilar metals joined at a point called a junction. A thermocouple produces a small voltage that is temperature dependent.

TIA Portal

Siemens Totally Integrated Automation Portal. Software used for designing, commissioning, operating, maintaining, and upgrading automation systems.

volatile memory

Used to describe a type of memory that requires continual application of power to prevent data loss.

web server

A computer or software that allows information to be displayed using standard Internet protocols.

work memory

Volatile storage for some elements of the user program.