Samson Series 420 Manual - Ation

 14  

EB 7500 EN

Design and principle of operation

Fig. 6: Type 3421 Compact Controller

1.1 Housing

1.2 Plug-in unit

1.3 Controller module

1.4 Connecting plate

2

Set point pointer (green)

3

Controlled variable pointer (red)

4

Control signal yA

5

Control signal yH

9

Manual adjuster for yH

10 Manual/automatic switchover

11 Set point adjuster

14 Selector switch (w

ext

/w

intern

)

5  Design and principle of oper-

ation

The pneumatic control system has a modular 

design. As a result, the compact control 

equipment can be combined with various 

controller modules and additional modules 

and adapted to a wide range of applica-

tions.

5.1  Type 3421CompactCon-

troller

The Type 3421 Pneumatic Compact Control-

ler consists of the Type 3422 Manual Control 

Station and the Type 3423 Controller Mod-

ule.

The manual control station consists mainly of 

the housing (1.1) with connecting plate (1.4) 

and the plug-in unit (1.2) to hold the control-

ler module (1.3). The plug-in unit has self-

seal push-on fittings, allowing the device to 

also function as a control station when no 

other components are used.

The controlled variable and set point pointers 

have metal bellows measuring elements. The 

controlled variable measuring element can 

optionally be equipped with adjustable in-

ductive limit contacts or LEDs.

Three versions of the Type 3422 Manual 

Control Station are available, which are 

adapted to the control task. Depending on 

the circuit version 1, 2 or 9, the device does 

not have the set point adjuster (11), set point 

pointer (2), or selector switch (14) for inter-

nal (w

int

) or external (w

ext

) reference variable.

All circuit versions have the ports R (feed-

back) and y (output pressure) connected in-

ternally to the connecting plate of the com-

pact controller.

In case y and R are to be routed separately 

out of the device, proceed as described in 

section 7.1 by relocating the O-rings on the 

connecting plate.

1.4

1.1

1.3

1.2

14

9

5

4

3

2

10

11