SAMSON 6111 technology data

System 6000
Electropneumatic Converters for Direct Current Signals
i/p Converter Type 6111

Application

Instruments used to convert direct current input signals into
pneumatic output signals for measuring and control tasks.
Especially suitable as intermediate element between electric
measuring devices and pneumatic controllers (or between
electric control devices and pneumatic control valves).

These converters are designed for use in all kinds of industrial
applications, especially in the field of process engineering.

The converters accept a load-independent 4 to 20 mA or 0 to
20 mA direct current input signal which they convert into a
pneumatic output signal.

Wide output pressure ranges can be selected for the Type 6111
i/p Converter by installing various converter modules (see Tech
nical data). The maximum output pressure that can be achieved
is 8 bar.

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Special features

• Wide selection of measuring ranges

• High output pressures up to 8 bar

• Easy replacement of i/p module

• Zero reset at specific mA-value when switch-off electronic
function is activated (function can be activated as required)

• Operation possible without an upstream pressure regulator

• Version designed as rail-mounting unit with plastic housing
or as field unit for offshore applications in a stainless steel
enclosure

•

Supply air manifold for rail-mounting units available as
accessories for 3, 4, 5 and 6 converter units (Fig. 4)

Versions

•

Type 6111 designed as rail-mounting unit (Fig. 1) · Suitable
for snap-on mounting on a top-hat rail

•

Type 6111 designed as field unit for offshore applications
(Fig. 2) · Mounted using a bracket

Special versions (on request)

•

Input signal 0 (2) to 10 V with Type 6151 Module

•

Electric connection with an angle connector according to
DIN EN 175301-803 A

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AS-Interface connection over Type 6150 Module

Fig. 1 · Type 6111 as rail-mounting unit

Fig. 2 · Type 6111 as field unit for offshore applications

Edition May 2007

Data Sheet T 6111 EN

Principle of operation (Fig. 3)

Electropneumatic converters essentially consist of an i/p con
verter module operating according to the force-balance princi
ple and a connected volume booster.

When operated, the supplied direct current (4) flows through
the plunger coil (2) in the field of the permanent magnet (3). At
the balance beam (1), theforce of theplunger coil, whichis pro
portional to the current, is balanced against the force of the
back-pressure. The back-pressure is produced on the flapper
plate (6) by the air jet leaving the nozzle (7).

The nozzle is supplied with air from the pneumatic output (36).
At an input signal of0 mA, an output pressureof approximately
50 to 80 mbar already exists due to the offset spring.

The supply air (9) flowsin the lower diaphragm chamber, and a
certain amount flows to the output. When the current increases,
the flapper moves closer to the nozzle. The force of the resulting
back-pressure pushes both the diaphragm (5) and sleeve (8)
downwards, allowing additional air to enter the chamber. The
passing air volume increases until the forces on the diaphragm
obtain a state of equilibrium. When the current decreases, this
action isreversed. The back-pressure created by the nozzleand
flapper decreases, and the diaphragm is pressed upwards. In
this process, it releases the sleeve, if applicable, and opens the
vent (11) untilthe forces onthe diaphragm arebalanced again.

Devices with an input signal range from 4 to 20 mA have a
slide switch which activates the switch-off electronic function.
This function causes the pneumatic output to be vented up to
approx. 100 mbar when the input signal falls below 4.08 mA ±
tolerance. In this way, the tight shut-off function of a valve can
be guaranteed.

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1 Balance beam
2 Plunger coil
3 Permanent magnet
4 Input
5 Diaphragm
6 Flapper plate

Fig. 3 · Functional diagram

7 Nozzle
8 Sleeve
9 Supply air
11 Vent
36 Output

Fig. 4 · Supply air manifold for Type 6111

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T 6111 EN