Design of Mechatronic System

EMT 2409: DESIGN OF MECHATRONIC SYSTEMS II

4th Year 2nd Semester 2012/2013.

CAT 1.

Time: 1 Hour

(a) Attempt ALL the questions.

INSTRUCTIONS

(b) Use NEAT and CLEAR diagrams.

A grain store is to be modernized. The operation of the grain store is as follows:

• The grain is tipped into a pit and transported from there into a cyclone by means of an

elevator (conveyor belt with scoops).

• The cyclone separates the grain from the chaff, which is blown away.

• The heavier grain drops downwards and is transported by a conveyor worm into a silo.

To ensure that neither the cyclone nor the conveyor worm is overloaded, the system must be

switched on as follows:

The following conditions additionally apply:

• Switching off must be carried out in the reverse order.

• The process is started automatically by detection of a truck in the delivery area

through a sensor.

• The elevator may be stopped either by a signal from a high-level sensor in the silo

indicating the silo is full or by a signal from a low level sensor in the delivery pit

indicating that the pit is empty.

• If the process had been stopped by the high level sensor in the silo, and the status of

the sensor changes, the process may be restarted, given the low-level sensor in the pit

indicates presence of grain in the pit.

(i) Identify all the inputs and outputs and draw a configuration table indicating variable

names.

(ii) Draw a flowchart to illustrate the process.

(iii) Write a ladder- logic program to automate the process, with comments explaining

each rung.