Samson 4763, Mounting And Operating Instructions

In the absence of such specifications, pro-

ceed as follows:

Required supply pressure =

Upper bench range value + 1 bar
The positioner output pressure is led to the

top or bottom diaphragm case of the actua-

tor as shown in Figs. 7 to 10.

4

Operation

4.1 Combining positioner and

actuator

The arrangement of the actuator, input sig-

nal, operating direction and mounting loca-

tion is schematically represented in Figs. 7

to 10.
Each subsequent change such as reversal of

the control loop's operating direction or field

reversing the actuator version from direct

"Actuator stem extends" to reverse "Actuator

stem retracts" or vice versa also involves

changing the mounting location of the

positioner.

4.1.1 Determining/reversing the

operating direction

(Figs. 7 to 11)
When the input signal (reference variable w)

increases, the signal pressure p

st

can either

be increasing (direct operating direction <<)

or decreasing (reverse operating direction

<>). The same applies to a decreasing input

signal; the output pressure either decreases

(direct operating direction <<) or increases

(reverse operating direction <>). Symbols

are located on the flapper (10.2) which

identify the respective operating directions

(direct << or reverse <>).
Depending on the flapper position, the ad-

justed operating direction is marked with the

corresponding symbol. If the operating di-

rection of the required function does not

match the symbol or if the operating direc-

tion is to be changed, proceed as follows:
1. Remove both screws of the cover plate,

and lift off the nozzle block (10) along

with the cover plate.

2. Reinstall the nozzle block turned 180° to-

gether with the cover plate, and screw

tight.

Make sure that the nozzle block and flapper

are correctly located above or below the

feeler pin (9.1) as shown in Fig. 11.
If the operating direction is to be changed

after the initially determined arrangement of

positioner and actuator, note that the

positioner must be mounted in a different lo-

cation and the nozzle block must be turned.

Always consider the location of the lever (1)

and the plate (20), "lever on top of plate" or

reversed "plate on top of lever" as shown in

Figs. 7 to 10.

12

EB 8359-2 EN

Operation