12.1.2. PLC I/O Mode

In PLC I/O mode there is no ZPA logic operating in the module, so the motors are independently controlled by default when the module is placed in PLC I/O mode. With a remote PLC you can connect to the PLC I/O Assemblies and either control each motor independently with your logic or utilize some specific specialized programming to couple the motors together so that the on-board firmware manages the master/slave control of the motors.

Open Loop

If open loop control is acceptable for your application, simply set both motors to open loop and use the same settings in EasyRoll and write your PLC logic to run both motors at the same time and in the same direction.

Closed Loop

You have two choices if you wish to used closed loop speed control: Independent and Master/Slave.

Independent

With this method you set up closed loop as described above for ZPA mode. In your PLC logic, you must run both motors at the same time and in the same direction.

Master / Slave

The ConveyLinx Module firmware has the capability when in PLC I/O mode to operate both motors at the same time by setting one motor as a master and its settings will be used for both motors. With this method, your PLC logic first configures the functionality and then only logically controls the master motor.

Unfortunately, the register to configure this functionality (4:0015) is not included in any of the PLC I/O mode assemblies. Your PLC code must utilize a MSG instruction to write to this configuration register.

The data is to be written to Register 4:0015 based on the following:

• Bit 0: Set for Left motor to be Master
• Bit 1: Set to make Right motor rotate opposite direction when Left is Master
• Bit 2: Set Right motor to be Master
• Bit 3: Set to make Left motor rotate opposite direction when Right is Master
• Bit 4: Always set to enable the functionality
  

*Programming Tip: You can set up your MSG instruction to continually write to Register 15, even though the ConveyLinx Module only needs to get written to once. If continually sending a MSG instruction is of concern for conservation of PLC resources; you can monitor the module’s Reset Counter register or AOI Module Enable bit to trigger the MSG write to register 15 only when you detect the module has power cycled or re-booted

You should use these bits as pairs. Either use bits 0 and 1 or use bits 2 and 3. Setting both bits 0 and 2 will not work.
For example, if you set bit 0, then your program logic only needs to control the Left motor in the PLC I/O instance assembly and the Right motor will have its settings internally controlled by the module.

!Please note when using Master/Slave motor control, the ConveyLinx Module ignores the EasyRoll settings for the slave motor

!In 2 motor coupled conveyor application, always remember to never set bits 1 or 3