SAMSON Type 3434 Pneumatic Controller Module

Pneumatic control core: Type 3434 controller module

In the field of industrial process control, pneumatic controllers are still widely used in industries such as chemical, petroleum, and pharmaceutical due to their inherent safety, resistance to electromagnetic interference, and suitability for flammable and explosive environments. As a key component of the Type 3430 pneumatic controller series, the Type 3434 controller module provides a flexible and reliable control solution for pneumatic control systems with its low-cost modular design. This article will provide a comprehensive and in-depth technical analysis of the controller module from the aspects of application scenarios, working principles, model versions, technical specifications, and selection points.

Product Application and Positioning

The Type 3434 controller module is specifically designed for installation in the Type 3430 pneumatic controller. The Type 3430 series is a classic on-site pneumatic control station widely used for adjusting process parameters such as pressure, temperature, and flow rate. The Type 3434 module serves as its core control unit, receiving pneumatic input signals ranging from 0.2 to 1 bar (3 to 15 psi) and outputting pneumatic signals within the same range. The gas supply pressure requirement is 1.4 bar (20 psi), which meets the standard industrial pneumatic signal range.

The plug design of this module perfectly matches the self sealing connector of the controller station and is secured with fastening screws to ensure a secure and leak free installation. The characteristic of self sealing connectors is that when the module is pulled out, the connector automatically closes to prevent gas leakage and facilitate online replacement or maintenance.

Working principle: force balance comparator

The core of the Type 3434 controller module is a box comparator that operates based on the principle of force balance. The principle of force balance is a classic closed-loop control mechanism in pneumatic instruments:

The input signal (measured value) generates a force through a bellows or diaphragm.

The set value generates a reference force through another component.

The difference between two forces drives the baffle nozzle mechanism, changes the back pressure, and thus controls the output pressure.

The output pressure is simultaneously fed back to the comparator, forming a closed loop until the force reaches equilibrium.

This design has high precision, high repeatability, and good anti vibration performance. The proportional action coefficient Kp (i.e. gain) can be continuously adjusted between 1 and 20 through a limiter to adapt to the time constants and load characteristics of different processes.

Model Version

According to different control functions, the Type 3434 controller module offers multiple versions. This data manual focuses on the following two basic models. For more P, PI, PD, and PID versions, as well as special control task modules, please refer to data sheet T 7040 EN.

1. Type 3434-1: P Control Function (Proportional Controller)

Type 3434-1 (Figure 1) achieves pure proportional control and has a fixed operating point. Proportional control outputs proportionally based on the magnitude of the deviation, with the formula: output=Kp x deviation+operating point. This model has a simple structure and fast response, suitable for situations where static error is allowed and load changes are not significant, such as pressure control of buffer tanks or non critical temperature control. Fixed working point means that when the deviation is zero, the output stabilizes at the preset bias value (usually the valve position corresponding to 0.2 bar or 3 psi).

2. Type 3434-2: PI Control Function (Proportional Integral Controller)

Type 3434-2 (Figure 2) implements proportional integral control. The integral function can eliminate static errors and make the controlled variable accurately equal to the set value during long-term operation. The PI controller is suitable for situations where the load changes frequently or where high control accuracy is required, such as temperature control of distillation columns, pressure control of reactors, etc. The integration time can be adjusted through an internal throttle (although the specific range is not listed in this data manual, the integration time of a typical pneumatic PI module can range from a few seconds to a few minutes). Compared to pure P control, PI control adds an integral element and the internal structure of the module is more complex, including integral gas volume and throttle valve.

Signal and gas path connection

The input and output signals of the Type 3434 module are all standard pneumatic signals:

Input signal (measured value): 0.2~1 bar (3~15 psi)

Output signal (control output): 0.2~1 bar (3~15 psi)

Gas supply pressure: 1.4 bar (20 psi) ± 10%

The gas supply pressure must be stable at 1.4 bar. If it is too high, it will damage internal components, and if it is too low, it will not be able to achieve full range output. The module adopts a plug-in design, and when the plug is inserted into the self sealing connector of the controller station, the air circuit is automatically connected; When pulled out, the connector automatically closes, without causing gas waste or system pressure loss. Tightening screws provide mechanical locking to prevent loosening caused by vibration.