The MAST Task in Implicit Exchanges

Task Management

This topic explains implicit messaging and the relationship between the MAST task configuration and the remote I/O implicit exchanges.

Implicit messaging maintains open connections for real-time communications of a predefined nature between consumers and producers. Implicit messages contain control data and a connection identifier.

EtherNet/IP uses the TCP/IP and UDP/IP protocols to implement both explicit and implicit messaging.

Access the MAST Configuration

View the Properties of MAST:

Step	Action
1	Go to the Properties of MAST dialog box in Control Expert (Tools > Project Browser > Project > Program > Tasks > MAST).
2	Right-click Properties.
3	Configure the parameters.

CIP Definitions

Inputs: The MAST period should be 2 times the RPI of the 140CRA31200 or BMXCRA312•0 adapter on the remote I/O drop. This provides new input values for every MAST cycle. (For example, an RPI of 25 ms provides data for a MAST period of 50 ms.)

Outputs: The CPU in the local rack of a Quantum Ethernet I/O system produces outputs to Ethernet remote I/O drops and consumes inputs from those drops (based on the producer/consumer model). A consumer (the remote drop) detects the lack of updated data through a time-out. (Possible time-out values are N x RPI, where N = 4, 8, 16 ....) When a time-out is triggered, the consumer assumes that the producer is absent.

Periodic and Cyclic Modes

The effect that periodic and cyclic modes have on implicit messages is explained in the description of the connection parameters.

Quantum I/O Management for Implicit I/O Exchanges

Assign state RAM addresses:

Drop type	Instruction
Quantum Ethernet remote I/O	The direct state RAM address manages the Quantum I/O data. Assign the state RAM addresses for each module. (Default values are proposed by Control Expert in the module configuration windows.) You can also define symbols on the I/O variables allocated in the state RAM.
Modicon X80 Ethernet remote I/O	To assign state RAM addresses for Modicon X80 I/O data, refer to the topic Device DDT Names for Quantum EIO adapters

Drop type

Instruction

Quantum Ethernet remote I/O

The direct state RAM address manages the Quantum I/O data.

Assign the state RAM addresses for each module. (Default values are proposed by Control Expert in the module configuration windows.) You can also define symbols on the I/O variables allocated in the state RAM.

Modicon X80 Ethernet remote I/O

To assign state RAM addresses for Modicon X80 I/O data, refer to the topic Device DDT Names for Quantum EIO adapters