What is the examine if closed instruction?
The XIC, also known as Examine If Closed, instruction is one of the fundamental instructions used in ladder logic programming for Programmable Logic Controllers (PLCs). This instruction is always found on the left side of a ladder rung and will verify if the specified bit is in a logic HIGH state.
What is examine if open?
Examine if Open (XIO) [Command Table] [Main Course Page] [Group Index] Use an XIO instruction in your ladder program to determine if a bit is Off. When the instruction is executed, if the bit address is off (0), then the instruction is evaluated as TRUE.
What is the examine if open Xio instruction asking the processor to examine?
This XIO instruction “asks” the processor of the PLC to examine if the contact is open. The processor does this by examining the bit at the memory location which is specified by the address: Depending on the status of the input device or internal address, the memory bit is set to 1 or 0.
What does XIC and XIO mean?
XIO basically means examine if open. Which means our rung will only be looked at by our ladder program if the switch is open. XIC means examine if closed so our rung will only be evaluated if our switch is closed.
Is the input device of PLC?
In a PLC system there will usually be dedicated modules for inputs and dedicated modules for outputs. An input module detects the status of input signals such as push-buttons, switches, temperature sensors, etc.. An output module controls devices such as relays, motor starters, lights, etc.
What is the input status of an open switch stored as?
The status bit of switches and pushbuttons connected to a PLC are stored in the: Input image table file. The scan is normally a sequential process of: Reading the status of inputs, evaluating the control logic and energizing or de-energizing the outputs.
What is a coil in PLC programming?
Contacts and coils are discrete programming elements, dealing with Boolean (1 and 0; on and off; true and false) variable states. Each contact in a Ladder Diagram PLC program represents the reading of a single bit in memory, while each coil represents the writing of a single bit in memory.
How does an internal control relay works?
Internal relays are coils and contacts that are simulated by the PLC in memory. Like external relays, they consist of an output coil and a set of contacts that can be used as the input to other objects on a ladder rung. This true state is fed back into the input to the normally closed contacts of the timer.
Where is the logic status of the input devices stored?
The Programmable Logic Controller stores the application program in the program memory and stores the status of the inputs and outputs in the data memory.
What does Xio mean?
The name Xio is primarily a gender-neutral name of Spanish origin that means Ready For Battle.
What is PLC scan cycle?
The scan cycle is the cycle in which the PLC gathers the inputs, runs your PLC program, and then updates the outputs. This will take some amount of time often measured in milliseconds (ms). The amount of time it takes for the PLC to make one scan cycle is called the scan time of the PLC.
Which is an example of examine if open?
Examine if Open (XIO) When the instruction is executed, if the bit addressed is on (1), then the instruction is evaluated as FALSE. This command is used on the left side of the ladder logic and is wired to an input such as I:0/3. A pushbutton or switch is an example of what can be wired to the input.
How to check if an open instruction is true?
Examine if Open (XIO) [Command Table] [Main Course Page] [Group Index] Use an XIOinstruction in your ladder program to determine if a bit is Off. When the instruction is executed, if the bit address is off (0), then the instruction is evaluated as TRUE.
What does examine if closed in OTE do?
Examine if Closed (XIC) This command is usually used in conjunction with the OTE command or a timer. This instruction functions as an input or a storage bit. If a 1 is input to the XIC instruction, it will allow the rung outputs to energize. If a 0 is input to the XIC instruction, it will de-energize the rung outputs.
What happens when the bit addressed is off in examine if closed?
When the instruction is executed, if the bit addressed is on (1), then the instruction is evaluated as TRUE. When the instruction is executed, if the bit addressed is off (0), then the instruction is evaluated as FALSE. This command is used on the left side of the ladder logic and is wired to an input such as I:0/4.
