Mitsubishi PLC Programming A Program consists sequence of instructions with Device name and address. Specific device is identified by its address. we know that controller have multiple input and output and each input and out have deferent address. where instructions perform a specific operation like counter are used for counting bit increment/decrement, arithmetic instructions perform addition subtraction, multiplication or other mathematics operation. In a Mitsubishi have predefined Device type which are used for different purpose for example A timer device used only for timer instruction. In Mitsubishi PLC Programming Device represented by A latter followed by Number. for example X0 where X is input device and 0 is the specific device address. Below image represent A timer device with Address. in this example timer Device specified as letter T and it's Address is 0.

What are Devices in Mitsubishi Plc Programming?

A device is a internal memory of Plc with specific address. in a Plc program when Device is declared than plc access particular device and process the input or output. each device have specific property that tell to controller to which type of data stored in a memory. these device are specified with predefined letter for example a input device specify by letter X. these memory hold or store processed data. in a Mitsubishi plc programming device reference has two parts

• The Device Name
• the Device Address

to read specific inputs and outputs you need to specify both the device name and address. below is the example have used two device first is X0 which are used as input device and Address of X is 0 and second is Y0, Y is a Output Device with specific address 0.Mitsubishi PLCs have predefined types of devices, each with a specific purpose. These are typically represented by letters followed by numbers. The following are common types of devices in Mitsubishi PLCs:

• Mitsubishi Input Devices (X)
• Mitsubishi Output Devices (Y)
• Mitsubishi internal Relays Devices (M)
• Mitsubishi Timers Devices (T)
• Mitsubishi Counter Devices (C)
• Mitsubishi Data Registers Devices (D)
• Mitsubishi Special Registers Devices (SD)
• Mitsubishi Index Registers Devices (V, Z)

What is Mitsubishi Input Devices (X)

A input Device is a Physical inputs from sensors. input device is represent as letter X followed by Address example X000, X0001 etc. below is the image shows both physical input and output. these device have only two state On and Off if the when the voltage at the input terminal is reached to 24 VDC than input device is set to ON state otherwise Input state is OFF. it means controller not control Input Devices. state of input devices is depend on sensor or switches.

What is Mitsubishi Output Devices (Y)

A Output Device is a Physical outputs of plc when instruction is executed. Output device is represent as letter Y followed by address example Y0000, Y0001, Y0002, Y0003 etc. Physical outputs is depend on program or logic. if an output instruction is executed on an output the result of current operation is applied to the output terminal. for example if we have a push button on input terminal X0 and a lamp on output terminal Y0 when push button is pressed our output is set to high(24VDC).

Example Of Mitsubishi input and Output Devices Connection

in above example we have a limit switch (LM1) connected to terminal zero it means the input device address is X0 and a lamp (out 0) is connected to Y0 terminal it means lamp address is Y0. in above program when limit switch is operated lamp is On otherwise off. if the limit switch is operated than input terminal voltage(X0) is set to 24VDC it change state of input device OFF to ON so X0 in a program is automatically set to ON and our output is also ON.

What is Mitsubishi internal Relays Devices (M)

Mitsubishi internal Relays Devices are internal memory of Controller. Internal relays are not a physical device.it is used to store binary result temporary for future reference. you can also used same result more than once. These devices store only bit form either 0 or 1. Plc have special memory cell to store these data called auxiliary relays. Mitsubishi internal Relays Device is represent as letter M followed by address example M0000, M0001, M0002, M0003 etc. Mitsubishi have some special relays which are known as special or diagnostic relays. these special relays address starting from M8000 we dicuss these relays in some another article.

in above example we have push button and we stored a push button state in a internal memory relay device (M0).when push button is pressed internal memory relay M0 store high value(1) same value we used as input of lamp.

What is Mitsubishi Timers Devices (T)

Mitsubishi Timers Devices (T) are used for timer. we know timer instruction are used to delay start and stop of operation. these timers are internal part of plc. timer hold bit value. for example in below program we have a on delay timer to delay on time of motor. when physical push button is pressed physical input is set to high and timer start increment when timer accumulator value reached to preset value i.e. K30 than timer output is set to high and motor start. you can use same timer state (1 or 0) to anywhere in a same controller but remember it only store a bit value with same address

in above program we used same timer value multiple times in a program. in a second rung if the timer is running than timer running output is high. second rung output is high when timer accumulator value reached to preset value.

What is Mitsubishi Counter Devices (C)

Mitsubishi Counter Devices (C) are used to stored counter state. it represented as C000, C001etc. it also stored bit value. counter devices store state of counter output. for example if the counter is increment than counter bit high when counter actual value is equal to counter preset value. you can use same counter value in multiple time with same address.

above is the example of counter devices where we use C0000 as a counter device. when counter value is reached to counter preset value than C0000 is high. in second rung reset counter value to 0 when input of this rung is set to high.

What is Mitsubishi Data Registers Devices (D)

Mitsubishi Data Registers Devices (D) are used to stored numerical (decimal) value. it represented as D0, D1 etc. these devices used for arithmetic instruction, analog signal instruction. a value that the program writes to a data register remain unchanged until the program overwrites it with another value. A memory range of these device are

• For 16 bit controller range - 0000H to FFFFH(-32768 to 32767)
• For 32 bit controller range - 00000000 to FFFFFFFFH(-2147483648 to 2147483647 )

above is the example of data register with addition instruction in this program value of D0 and D1 are added and the result is stored in D2.

Note:- Mitsubishi have some special register and relays which we discuss on another article.