Introduction: HOME I/O- PLC Interfacing

Picture of HOME I/O- PLC Interfacing

PLC Interfacing- Digital Control of Home I/O using PLC – Allen Bradley

Starting Conditions: Home I/O is being controlled by Inbuilt Sensors I/O Signals

Inputs:

  • Entrance gate Closed (Bit 261)
  • Entrance gate Opened (Bit 260)

Output:

  • Entrance gate Open (Bit 193)
  • Entrance Gate Closed (Bit 194)

Connect I/O Functions to be used

Source Bit

Note: This activity is extended to the Activity 1 in which we controlled the Gate Latching/Unlatching via Connect I/O Logic. Here we are going to perform the similar operation using PLC Ladder Logic

Step 1: Wiring Diagram With USB 4704 DAQ Card I/O Solutions:

Picture of Wiring Diagram With USB 4704 DAQ Card I/O Solutions:

PLC Input Wiring:

We have connected Input IN8 & IN9 to Digital Output DO0 & DO1 respectively. The Common of PLC Input is connected to the Digital Ground of DAQ Card.

PLC Output Wiring:

PLC Output OUT 0 & OUT 1 is connected to Digital Input DI0 & DI1 of DAQ Card. Whereas the Common of PLC output is connected to Digital Ground of Input terminals of DAQ Card.

Step 2: Connect I/O Interface Connection

Picture of Connect I/O Interface Connection

To read/write the values in PLC, we have made the following connection in Connect I/O Software.

Step 3: Description of the Functions Used:

Picture of Description of the Functions Used:

Source Bit: This is an ON/OFF bit used to give TRUE/FALSE Signal to Logical gates. When you press it once, it goes to TRUE & when you press is again it goes to FALSE

Bit 193: Entrance Gate (Open): This is the standardized bit used to open the Entrance gate

BIT 260: Entrance gate (Opened): This bit gives feedback for the Gate 1. When Gate 1 is fully opened, it gets ON else its OFF.

Bit 194: Entrance Gate (Close): This is the standardized bit used to close the Entrance gate

BIT 261: Entrance gate (Closed): This bit gives feedback for the Gate 1. When Gate 1 is fully closed, it gets ON else its OFF.

Step 4: Explanation of Solutions:

Picture of Explanation of Solutions:

PLC INTERFACING- Digital Control of Home I/O using PLC –Allen Bradley

In this ladder Logic we have used Latch/ Unlatch commands to make the logic little easy to follow.

Following is the brief explanation of the ladders:

  • In Ladder 0000: The Internal Bit B3:0/0 is used to Latch the Output O:0/0.
  • In Ladder 0001: Input I:0/9 is used to Unlatch the Output O:0/0
  • In Ladder 0002: The Internal Bit B3:0/1 is used to Latch the Output O:0/1.
  • In Ladder 0003: Input I:0/8 is used to Unlatch the Output O:0/1

This logic has been made in Rs Logix 500- PLC Programming Software for Allen Bradley.

Step 5: To Latch/Unlatch the Gate in Home Using PLC Logics

Picture of To Latch/Unlatch the Gate in Home Using PLC Logics

Step 1: Latching the Opening of Door using Rising Edge of Sensor 1

We have used internal bit of PLC B3:0/0 for illustration purpose to latch the PLC Output O:0/0. As discussed above, this Output is connected to DAQ Input IDI0.

Hence, it latches the Gate Open Bit 193 & opens the door.

Step 6: Unlatching the Output Bit When Door Is Fully Opened.

Picture of Unlatching the Output Bit When Door Is Fully Opened.

Here, when the gate is fully opened, we get the True condition of Entrance Gate Opened Bit -260 which is connected to IDO1 of DAQ Card.

Hence, PLC Input I:0/9 which respond to the Entrance Gate Opened Bit-260 connected at IDO1 unlatches the O:0./0 which further Turns OFF the Entrance Gate Open Bit 193 & stops opening of gate.

Step 7: Latching the Close Operation Using Infrared 2

Picture of Latching the Close Operation Using Infrared 2

Here, We have used internal bit of PLC B3:0/1 to latch the PLC Output O:0/1. As discussed above, this Output is connected to DAQ Input IDI0.

Hence, it latches the Gate Open Bit 194 & closes the door.

Step 8: Unlatching the Output Bit Using Gate Closed Bit

Picture of Unlatching the Output Bit Using Gate Closed Bit

Similar to step 2, when the gate is fully closed, we get the True condition of Entrance Gate Closed Bit -261 which is connected to IDO0 of DAQ Card.

Hence, PLC Input I:0/8 which respond to the Entrance Gate Closed Bit-261 connected at IDO0 unlatches the O:0./1 which further Turns OFF the Entrance Gate Close Bit 194 & stops closing of gate.

Want to PLC, explore our E-Learning courses at http://online.nfiautomation.org

Check out the Video Demonstration: https://www.youtube.com/watch?v=vSlqrqjDVOw

Comments

ringai (author)2015-04-13

Very impressive!

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