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RT 552 pH-Value Control Trainer
Education / GUNT Hamburg / Process Engineering / Simple Process Engineering Control Systems /

This trainer provides a comprehensive experimental introduction to the fundamentals of control engineering using an example of continuous pH control.

  A caustic solution is added to fresh water by way of a metering pump. The pH-value of this solution is measured. The acid is then added to the solution as a neutralising reagent by way of a second metering pump. The chemical reaction occurs in a pipeline system. The pH-value is then remeasured. A state-of-the-art digital industrial controller controls the second metering pump with reference to this pH-value. The neutralised solution flows into the product tank. A third manual measurement of the pH-value in the product tank permits disposal of solution with a neutral pH-value. The pH-value of the input solution can be varied by manually adjusting the metering pump or by varying the quantity of fresh water. This enables disturbances to be simulated. The controlled variable X and the manipulating variable Y are plotted directly on an integrated 2-channel line recorder. Alternatively, the variables can be tapped as analogue signals at lab jacks on the switch cabinet. This enables external recording equipment, such as an oscilloscope or a flatbed plotter, to be connected.

  A process control software (RT 650.50) is optionally available. The software permits the construction of a complete networked system comprising multiple trainers from the RT 512 - RT 552 series. The key process variables can also be represented, and control functions executed.


  The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.


Learning Objectives / Experiments

- fundamentals of control engineering
- real industrial control engineering 
- operation and parameterisation of the local

  * manually
  * using the RT 650.50 process control software 
- pH-value control
  * influence of dead time
- ratio control
- investigation of disturbance and control response

- controller optimisation 
- properties of the open and closed control loops
- processing of process variables using external

  equipment, e.g. oscilloscope or plotter
- together with accessory RT 650.50 and other

  trainers (RT 512 - RT 542): familiarisation with and use of process control software (SCADA)


[1] trainer for control engineering experiments
[2] pH-value control process, equipped with standard industrial components
[3] neutralisation of a caustic solution with an acid 
[4] 2 pH-value sensors in transparent measuring tanks with overflow
[5] digital controller, parameterisable as a P, PI or PID controller
[6] product tank and 2 chemicals tanks
[7] 2 metering pumps: adjustable manually or via controller, max. flow rate 2,1L/h
[8] water connection with control valve and flowmeter
[9] corrosion-resistant piping system

[10] hand-held pH-meter for product control 
[11] 2-channel line recorder
[12] process variables X and Y accessible as analogue signals via lab jacks 

Technical Data

Product tank: 20L
Chemicals tank: 2x 5L
- acids and caustic solutions: in pH range 1...12
pH-value sensor, filled with solid electrolyte
- with glass shaft and PTFE diaphragm
Measuring ranges
- pH: 1...12
- temperature: 0...80°C
Line recorder
- 2x 4...20mA
- feed rate 0...3.600mm/h, stepped

- process variables X, Y as analogue signals: 4...20mA


Dimensions and Weight
LxWxH: 1.000x700x1.750mm
Weight: approx. 85kg
Required for Operation

230V, 50/60Hz, 1 phase or 120V, 60Hz/CSA, 1 phase
Water connection

Chemicals: caustic soda NaOH 45%; hydrochloric acid HCl 30%, technically pure; buffer solution pH4,0 (red), buffer solution pH7,0 (green), buffer solution pH10,0 (blue)

Scope of Delivery

1 trainer

1 hand-held pH-meter

3 measuring cups

1 set of cables

1 hose

1 set of instructional material

Order Details
080.55200  RT 552  pH-Value Control Trainer