BCD |
Binary Coded Decimal. A binary code in which each group of four consecutive binary bits represents a decimal digit (0 through 9). |
Binary Coded Decimal |
BCD. A binary code in which each group of four consecutive binary bits represents a decimal digit (0 through 9). |
Bit Logic Instructions |
A category of Instructions in the FBD programming language that performs logical operations using single bit memory locations. |
Boolean Logic |
A type of logic that deals with the use of logical functions such as OR, AND, and NOT. |
Byte |
8 consecutive bits or a data type for 8-bit bit strings. |
Data Block |
DB. 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 Type |
A classification that identifies how data in a memory location is interpreted. There are a variety of data types and they are often represented by shorthand names such as Int for a 16-bit signed integer or Real for 32-bit floating point values. |
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. |
DInt |
Signed Double Integer. A data type for 32-bit signed whole numbers. |
Double Word |
32 consecutive bits or a data type for 32-bit bit strings. |
FBD |
Function Block diagram programming. A graphical programming language defined in part 3 of the IEC 61131 standard. |
Function Block Diagram |
FBD. A graphical programming language defined in part 3 of the IEC 61131 standard. |
IEC 61131 |
A standard of the International Electrotechnical Commission that provides common approaches and concepts for PLCs. Part three of the standard describes the FBD programming language for PLCs. |
Int |
Signed integer. A data type for 16-bit signed whole numbers. |
Linear Program |
A PLC user program with all the instructions in the main program block (OB1). |
Negative Edge |
A 1 to 0 transition of a bit or the result of logic operation (RLO). |
Network |
A logical connection of instructions that represents one rung of an FBD program. These instructions are executed from left to right. |
OB1 |
Organization Block 1. The main program block in a Siemens PLC program. |
Operand |
A part of a PLC instruction that identifies a memory location associated with the instruction. |
Organization Block |
A type of program block in a Siemens PLC that interfaces the PLC operating system to the user program. Every program must have at least one OB. If it has only one OB, that block is identified as OB1. |
Organization Block 1 |
OB1. The main program block in a Siemens PLC program. |
Positive Edge |
A 0 to 1 transition of a bit or the result of logic operation (RLO). |
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). |
Real |
A data type designation for 32-bit floating point values. |
Result of Logic Operation |
RLO. The intermediate solution to a configuration of instructions. |
RLO |
Result of Logic operation. The intermediate solution to a configuration of instructions. |
Scan |
A repetitive process performed by a PLC CPU that includes updating input status, executing the user program, updating outputs and other important tasks. |
Signed Double Integer |
DInt. A data type for 32-bit signed whole numbers. |
Signed Integer |
Int. A data type for 16-bit signed whole numbers. |
STEP 7 |
Software used for the configuration, programming, testing, and diagnosis of Siemens SIMATIC S7 PLCs. |
STEP 7 (TIA Portal) |
Siemens STEP 7 PLC software within TIA Portal. |
Structured Program |
PLC programming that divides the user program into multiple program blocks. Depending upon how the program is structured, a specific program block may be executed in each scan of the user program or on a conditional basis. |
TIA Portal |
Siemens Totally Integrated Automation Portal. Software used for designing, commissioning, operating, maintaining, and upgrading automation systems. |
Word |
16 consecutive bits or a data type for 16-bit bit strings. |