Armfield PCT40 - Exercise G - Proportional Pressure Input with PID Controller Using Proportioning Solenoid Valve

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Exercise G - Proportional pressure input with PID
controller using Proportioning Solenoid Valve
Objective
To control the level in the process vessel with a PID controller, using a pressure
sensor to monitor the level with a Proportioning Solenoid Valve (PSV) controlling
inflow to the vessel.
Overview
The proportional pressure sensor sends a signal to the controller that varies with the
pressure on the sensor resulting from the depth of fluid. The controller sends a signal
to the Proportioning Solenoid Valve (PSV) that is proportional to the signal from the
sensor. The PSV then opens proportionally with the signal from the controller.
Equipment Required
PCT40 bench with large process vessel, inner cylinder and supplied flexible tubing.
Equipment set up
Ensure that the apparatus has been set up according to the Installation section.
Ensure that the inlet connector for the apparatus (on the right of the plinth behind the
pressure regulator) is connected to a suitable mains water supply. Check that the
central cylinder is securely in position inside large process vessel. Using a suitable
length of tubing, connect the self-sealing connection socket on the base of the large
process vessel to the quick release connection on the valve SOL1 at the front right of
the plinth.
The drain valve at the end of the plinth should be directed to a drain and left open.
Solenoid valves 2 and 3 should be connected to a suitable drain using the tubing
supplied. The drain valve in the base of the large process vessel should also be
connected directly to drain using flexible tubing.
Connect the apparatus to a suitable PC on which the software has been installed
using the pale grey USB cable supplied. The flat connector on the cable connects to
the PC, usually via a socket at the back. The other end connects to the socket on the
orange panel on the front of the plinth. Check that the PC is working and switched
on.
Procedure
Switch on mains power to the console. Valve PSV is Normally Closed, so flow into
the large process vessel will not occur until the valve is in operation.
Run the PCT40 software and select Section 2: Level Control (inflow).
Partially close the drain valve on the bottom of the large process vessel to slightly
reduce the outlet flow rate.
In the Sample menu, select ‘Configure...’ and check that the software is set to
Automatic sampling with a sample interval of 10 seconds and Continuous duration.
Click on the Control button.