Programming element for Mitsubishi FX2N series PLCs

Each element of the Mitsubishi FX2N series PLC is indicated by a characteristic letter, such as X indicates the input relay, Y indicates the output relay, M indicates the auxiliary relay, T indicates the timer, C indicates the condition element, etc., and these elements have a specified number.

Programming element for Mitsubishi FX2N series PLCs

Programming element for Mitsubishi FX2N series PLCs

1. Input relay (X)

The FX2N series programmable manipulator input relay is indicated with an "X", and the number scale is X0-X177 (up to 128 points, the number of points may be different for different models). The input relay is connected to the input terminal of the PLC, and is a component of the PLC to receive external switching signals (such as input signals such as switches, buttons, sensors, etc.). The input relay must be driven by an external signal and cannot be programmed. The contacts of the input relay can be used multiple times in the program without any restrictions. The FX2N type PLC input relay uses an octal address number up to 128 points (177 in octal is equal to 127 in decimal).

2. Auxiliary relay (M)

1. General auxiliary relay

Universal auxiliary relays are numbered according to the decimal address (in the FX type PLC, all equipment except the input relay and the output relay are numbered in the decimal address number).

2. Insist on auxiliary relay when power is off

If there is a power failure during the operation of the PLC, the output relay and the universal auxiliary relay will be disconnected. After power-on, except for the PLC when it is running and the external input signal is turned on, the others are still disconnected. The power-off insistence auxiliary relay can adhere to the condition before the power-off, and it is supported by the lithium battery built into the PLC.

3. Special auxiliary relay

There are 256 special auxiliary relays in the PLC, each of which has a specific function. It is generally divided into two main categories:

(1) A special auxiliary relay that can only be used with its contacts. The coil is automatically driven by a PLC and the user can only utilize its contacts. For example, M8000 is a relay for operation monitoring, M8000 is turned on when PLC is running, and M8002 is an initial pulse special auxiliary relay that is only turned on instantaneously at the beginning of operation; The M8012 is a special auxiliary relay that generates a clock pulse of 100 ms.

(2) Coil-type special auxiliary relay can be driven. After the user encourages the coil, the PLC does a specific action. Undefined special auxiliary relays can be used in user programs. The normally open and normally closed contacts of the auxiliary relay can be used in the PLC an infinite number of times.

3. Conditioner (S)

The condition device (S) is an important device that constitutes the condition transfer diagram, which is used in conjunction with the step-by-step control command. The conditioners of the FX2N series PLCs are shown in Table 7-1. S0-S499 does not have a power off to insist on function, but the program can set them to have a breakpoint to adhere to the function. The normally open and normally closed contacts of the conditioner can be used in the PLC and the number of applications is not limited. When the step sequential command is not used, the conditioner S can be used as an auxiliary relay M in the program. In addition, each condition relay is provided with a stepping contact, called an STL contact, which is used in a step-operated ladder diagram.

4. Timer (T)

The timer T in the PLC is equivalent to the time relay in the relay control system, which can provide unlimited pairs of normally open delay contacts and normally closed delay contacts for programming. The timer element number is numbered in decimal system, and the set time is determined by the programming time setting factor K. T0-T199 is a 0.1 s timer, the setting value scale is 0.1-3276.7 s, and the minimum unit is 0.1 s: T200-T245 is a 0.01 s timer, and the setting value scale is 0.01-327.67 s. In addition, there are also accumulator timers. When the drive input X000 of the timer coil T200 is turned on, the timer counter of T200 accumulates the clock pulse of 10 ms, and the time value is equal to the set value K123, and the output contact of the timer acts, that is, the output contact is operated at 1.23 s (10×123 ms=1.23 s) after the drive coil, and when the T200 contact is engaged, Y000 has an output. When the drive input X000 is disconnected or a power failure occurs, the timer is reset and the output contact is also reset.

Each timer only needs one input, it is the same as the conventional timer, when the coil is energized, the start of the timer; When the power is off, it automatically resets and does not save the center value. The timer has two data registers, one is a setpoint register and the other is a present value register, which is programmed and the cumulative value is set by the user.

When the drive input X001 of the timer coil T250 is turned on, the current value counter of the T250 accumulates the clock pulse of 100 ms, and when the value is equal to the set value K345, the output contact of the timer acts. During the counting process, even if the input X001 is connected or a call is coming, the counting continues with a cumulative time of 34.5 s (100 ms×345=34.5 s). When the reset input X002 is turned on, the timer is reset and the output contact is also reset.

5. Counter (C)

The counter part numbers are numbered in decimal system, and the number of counts of the counter is determined by the coefficient K set at the time of programming. It provides unlimited pairs of normally open and normally closed contacts for programming. C0-C99 is a general-purpose plus counter, and the counting scale is 1-32 767;C100-C199 is a power failure insistence plus counter, and the counting scale is 1-32 767. In addition, there are general addition and subtraction counters (C200-C219), power-failure insistence addition and subtraction counters (C220-C234) and high-speed counters (C235-C255), etc.

The 16-bit addition counter in the FX2N is a 16-bit binary addition counter that counts on the rising edge of the count signal. It has two inputs, one for reset and one for counting. The rising edge of each counting pulse subtracts the original value by 1, and when the current value is reduced to zero, the counting is stopped and the contact is closed. It is not until the rising edge input of the control signal is reset that the contact is disconnected, the set value is written again, and the counting state is entered. Its setpoint is valid in the K1 - K32 767 scale. The setting value K0 has the same meaning as K1, that is, when the first count is counted, its output contact is activated.

Each time the C0 coil is driven by the counting input X011, the current value of the counter is increased by 1. When the coil command is performed for the 10th time, the output contact of counter C0 is acted. After that, even if the counter enters X011 and then acts, the current value of the counter will remain unchanged. When the reset input X010 is turned on (ON), the RST command is executed, the counter is 0 at that time, and the output contact is also reset. It should be noted that even if a power failure occurs in the counter C100-C199, the operation or reset status of the current value and the output contact can be maintained.

6. Data Registers (D)

Data registers are essential components of a computer that hold all kinds of data. Each data register in the FX2N is 16 bits (the highest bits are positive and negative sign bits), and two data registers can be combined to store 32 bits of data (the highest bits are positive and negative sign bits). There are general data registers, power failure persistence registers, special registers, variable address registers, and file registers.

Programming element for Mitsubishi FX2N series PLCs

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