PLC Mixing Process with Adjustable Timer and Valve Control

This article discusses the PLC mixing process with adjustable timer and valve control using XG-5000 PLC Software. This Batch Mixing System has 3 Processes, Liquid Filling Process, Mixing Process, and Draining Process. When the Tank is empty, Valve 1 will automatically Open. This system uses HIGH & LOW sensors to detect the liquid contents in the Tank. When the Tank is fully filled, the Mixer will rotate and the Mixing Process time parameters can be Set. Valve 2 will automatically Open when the Mixing Process is complete. The quantity of Mixing Processes that have been carried out will be counted and can be Reset.

Contents

Program Objective

The PLC logic has these buttons and the following sensors:

The PB_START (P00000) button is used to Start the system.
The PB_STOP (P00001) button is used to Stop the system.
The RESET_COUNTER (P00004) button is used to Reset the Counter value.
The LOW_SENS (P00002) sensor is used to measure the lowest point of liquid in the tank. The sensor will be Active when it detects liquid.
The HIGH_SENS (P00003) sensor is used to measure the highest point of liquid in the tank. The sensor will be Active when it detects liquid.

The time parameter “Set Value” for the Mixing Process in the memory word SV_TIMER_MIXER (D00010) must be Set before the system is Started.

Liquid Filling Process

When the PB_START (P00000) button has been Pressed and the tank is empty, the LOW_SENS (P00002) sensor will be non-active and the Valve VALVE_INPUT (P00040) will be OPEN.

Valve VALVE_INPUT (P00040) will CLOSE when the HIGH_SENS (P00003) sensor is Active. This indicates that the liquid in the tank is full.

Mixing Process

When the Valve VALVE_INPUT (P00040) is CLOSED, the output MIXER (P00041) is to Mix the liquid.

The Mixing process will be completed when TIMER_MIXER (T0000) has finished counting and Output MIXER (P00041) becomes OFF.

Draining Process

When TIMER_MIXER (T0000) has finished counting, the Valve VALVE_OUT (P00042) will OPEN to drain the liquid from Tank.

Valve VALVE_OUT (P00042) will CLOSE again when the LOW_SENS (P00002) sensor is non-active.

When the entire process has been carried out, the Counter value in the memory word COUNTER_BATCH (D00000) will increase (+1).

PLC Mixing Process with Adjustable Timer and Valve Control

Addressing of Project

Comment	Input (I)	Output (Q)	Memory Word	Memory Bits	Timer
PB_START	P00000
PB_STOP	P00001
LOW_SENS	P00002
HIGH_SENS	P00003
RESET_COUNTER	P00004
VALVE_INPUT		P00040
MIXER		P00041
VALVE_OUT		P00042
SYSTEM_ON				M00000
TIMER_MIXER					T0000
COUNTER_BATCH			D00000
SV_TIMER_MIXER			D00010

Programming of PLC Code

RUNG 1

In this Rung, when the PB_START (P00000) button is Pressed, the memory bit SYSTEM_ON (M00000) will be in the HIGH state. Because it uses the SET Coil Instruction, the memory bit SYSTEM_ON (M00000) will remain in the HIGH state even though the PB_START (P00000) button has been Released.

PLC Liquid Filling and Mixing System Using Sensors and Timers

RUNG 4

Because it uses the RESET Coil Instruction, the memory bit SYSTEM_ON (M00000) will be in the LOW state if the PB_STOP (P00001) button is Pressed.

RUNG 7

In this Rung, the Output VALVE_INPUT (P00040) will be OPEN if the NO contact of memory bit SYSTEM_ON (M00000) is in the HIGH state. The VALVE_INPUT (P00040) output will be CLOSE when the NC contact of LOW_SENS (P00002) or HIGH_SENS (P00003) in the HIGH state.

PLC Automated Filling, Mixing, and Draining

RUNG 14

In this Rung, when the NO contact of memory bit SYSTEM_ON (M00000) and the HIGH_SENS (P00003) Sensor in the HIGH state, the MIXER (P00041) Output will be ON and the TIMER_MIXER (T0000) Timer will start counting.

When the TIMER_MIXER (T0000) Timer has finished counting, the MIXER Output (P00041) will be OFF.

RUNG 22

When the NO contact of memory bit SYSTEM_ON (M00000), Timer TIMER_MIXER (T0000), and LOW_SENS (P00002) Sensor in the HIGH state, the VALVE_OUT (P00042) Output will be OPEN.

The VALVE_OUT (P00042) Output will remain in the OPEN state even though the NO contact of TIMER_MIXER (T0000) Timer is in the LOW state because it uses the Latching Function.

The VALVE_OUT (P00042) Output will become CLOSE if there is NO contact with the LOW_SENS (P00002) Sensor or memory bit SYSTEM_ON (M00000), which becomes a LOW state.

PLC-Controlled Batch Mixing System Automated Liquid Fill, Mix, and Drain

RUNG 29

The memory word COUNTER_BATCH (D00000) will increase by (+1) when the NO contacts of VALVE_OUT (P00042) and memory bit SYSTEM_ON (M00000) are in the HIGH state.

The ADD instruction will add a value (+1) to the memory word COUNTER_BATCH (D00000) each time it is activated.

RUNG 37

In this Rung, the MOV Instruction will move the zero value “0” to word memory COUNTER_BATCH (D00000) when the RESET_COUNTER (P00004) button is Pressed.

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