Plast-O-Matic V200 Instructions

ELECTRO-PNEUMATIC POSITIONER
INSTALLATION AND MAINTENANCE

1. INTRODUCTION

1.1 Principal of Operation

The V200 incorporates the force balance principal of operation. The
desired value, in the form of pressure, affects the membrane (1) with
the force that is created and transferred to the balance arm (2). The
opposing force, which represents the actual control value, is provided
by the feedback spring (5) and creating force in the opposite direction
on the balance arm (2). The feedback spring, resting on the feedback
arm (3), is positioned by the shape and response of the cam. The cam
(4) is connected to the cylinder's (actuator) piston rod via the drive.
The pilot valve (6) is connected to the balance arm and follows the
balance arm's movement. The system is stable when the gold plated
spool (7) is in the neutral position and the forces that affect the balance
arm is in equilibrium. As soon as signal change occurs or a change in

1.3 Air quality recommendations

Poor air quality is one of the main causes of premature functional
problems with pneumatic and electro-pneumatic equipment. The pilot
valve and IP-converter are precision instruments, and are therefore
the most sensitive parts of the positioner.
a) Water in the supply air is a natural occurrence. This happens when
air is compressed. The compression heats the air and the natural
degree of water in the air can remain as moisture. When the air cools
in pipes etc. the moisture condenses and becomes liquid water. Large
quantities can build and sometimes flood small water separators. This
excess water will eventually reach the control valve and positioner.
This can cause corrosion damage to the IP converter, causing the unit
to malfunction.
We strongly recommend the use of water separators with adequate
capacity. Coalescing filters from a reputable manufacturer is an
inexpensive way to help prevent unit malfunctions or failures, and add
life to the product. These filters remove particles and moisture from
air lines.
IMPORTANT: READ BEFORE USE
INSTRUCTIONS
the position of the valve/actuator package occurs, the "force balance"
is also changed and the spool responds. Air immediately begins to
flow into the part of the actuator (C+ or C-) which allows the feedback
mechanism to return the spool to the neutral position.
The system is self-stabilizing and searches for a steady state position.

1.2 Product Identification

The V200 identification tags, Serial number tag (1), product model
tag (2) and feedback option tags (3) are placed as shown.
The product model tag contains information on control signal,
maximum working pressure and temperature ranges. Other
information can be shown depending on the model.
b) Oil in the supply air usually is from the main compressor. Oil can
clog the small nozzles and disturb the flapper in the IP-converter. It
can also cause the gold plated spool to "drag" within the pilot valve.
The result is poor control or in the worst case, failure.
c) Particles in the air usually occur because of corrosion. Dirt and
particles can block the small nozzles of the IP-converter. They can
also cause the pilot valve to malfunction. The unit may completely fail.
To ensure normal operational safety with VAC positioner products, we
recommend that a water separator and a <80 micrometer filter are
mounted as close to the product as possible. If large amounts of oil
are present an oil separator should be installed as well.
To further increase operational safety, we recommend that the
working air is clean, dry and free of moisture, water, oil, particles and
other contaminants, in accordance with the standard ANSI/SA –
7.0.01 – 1996.
EPP-0514-I-1