Mitsubishi PLC Based Sand Separator Logic

This article discusses the design of an automatic sand separator system using Mitsubishi PLC logic. The system is designed to separate sand from other materials using an automated sieving mechanism. It precisely measures the weight of the sand and regulates the sieving duration based on predefined parameters. To indicate the end of the process, the system is also equipped with an indicator alarm that activates automatically once the sieving is complete.

Contents

Program Objective

Operational Steps of the Sand Sieving System:

Set Initial Parameters
Specify the sieving time and sand weight before starting the system.
Automatic Weighing
The system measures the sand according to the set weight; the sliding valve opens, and the weighing indicator starts measuring.
Motor Activation
Once the target weight is reached, the motor activates to drive the sieve.
Sieving Process
The sieve operates for the specified duration, and the sieved sand is automatically collected.
Open Output Valve
After sieving is complete, the output sliding valve opens to discharge the remaining material.
Residual Discharge
The sieve gate opens along with the output valve, and both close when the remaining weight is less than 3 kg.
Process Completion Alarm
The alarm turns on as an indicator that the process is complete and turns off when the system is shut down.

PLC Program for Sand Separation and Alarm Control

IO Mapping Details

S.No.	Comment	Output(Q)	Memory Bit	Memory Word	TImers
1	START		M0
2	STOP		M1
3	SLIDING_VALVE_IN	Y000
4	MOTOR_SIEVE	Y001
5	SLIDING_VALVE_OUT	Y002
6	GATE_SIEVE_OUT	Y003
7	ALARM	Y004
8	SV_WEIGHT			D0
9	SV_TIME			D2
10	PV_WEIGHT			D4
11	TIMER_SIEVE				T0
12	SYSTEM_ON		M2
13	ILC_WEIGHT		M3

Mitsubishi PLC Based Logic

Ladder Logic for Sand Separator in GX Works2

RUNG 0

In this Rung, the memory bit SYSTEM_ON (M2) memory bit will be in a HIGH state if the START (M0) button is pressed and the value in the SV_WEIGHT (D0) and SV_TIME (D2) memory words is greater than zero “0”. Even though the START(M0) button has been released, the memory bit SYSTEM_ON (M2) will remain in a HIGH state. Because it uses Latching.

If the STOP(M1) button is pressed, the memory bit SYSTEM_ON (M2) will be in a LOW state.

RUNG 15

In this Rung, the SLIDING_VALVE_IN (Y000) output will be OPEN if the NO contact of the memory bit SYSTEM_ON (M2) is in a HIGH state.

The memory bit ILC_WEIGHT (M3) will be in HIGH state when the value in the memory word PV_WEIGHT (D4) is greater than or equal to SV_WEIGHT (D0).

The SLIDING_VALVE_IN (Y000) output will be CLOSED due to the Interlock.

RUNG 26

In this Rung, the MOTOR_SIEVE (Y001) output will be ON, and the TIMER_SIEVE (T0) timer will start counting when the NO contact of the memory bit ILC_WEIGHT (M3) is in the HIGH state. Although the memory bit ILC_WEIGHT (M3) has been in the LOW state, the MOTOR_SIEVE (Y001) output will remain ON. Because it uses Latching.

The MOTOR_SIEVE (Y001) output will be OFF because of the interlock of the TIMER_SIEVE (T0) timer.

RUNG 36

The SLIDING_VALVE_OUT (Y002) and GATE_SIEVE_OUT (Y003) outputs will be OPEN when the NO contact of the TIMER_SIEVE (T0) timer is in the HIGH state.

Even though the NO contact of the timer TIMER_SIEVE (T0) has been in the LOW state, the output SLIDING_VALVE_OUT (Y002) and GATE_SIEVE_OUT (Y003) will remain OPEN. Because it uses the SET instruction.

Complete Mitsubishi PLC Logic for Sand Separation

RUNG 40

In this Rung, the output SLIDING_VALVE_OUT (Y002) and GATE_SIEVE_OUT (Y003) will be CLOSED when the NO contact of the memory bit SYSTEM_ON (M2) is in the HIGH state and the value in the PV_WEIGHT memory word (D4) is less than “3”. Because it uses the RST instruction.

RUNG 48

When the NO contact of GATE_SIEVE_OUT (Y003) is in the HIGH state, the ALARM (Y004) output will be ON.

RUNG 51

If the STOP (M1) button is pressed, the ALARM (Y004) output will be OFF. Because it uses the RST instruction.

Mitsubhisi PLC Logic

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