Supply Pressure Connection; Remote Set Point (Suffix Letter M) Pressure Connection; Vent - Fisher 4194B Series Instruction Manual

The recommended slope is 1 inch per foot (83 millime-
ters per meter).

Supply Pressure Connection

WARNING
Personal injury or property damage may
occur from an uncontrolled process if
the supply medium is not clean, dry, oil-
free, or non-corrosive gas. Industry
instrument air quality standards de-
scribe acceptable dirt, oil, and moisture
content. Due to the variability in nature
of the problems these influences can
have on pneumatic equipment, Fisher
Controls has no technical basis to rec-
ommend the level of filtration equipment
required to prevent performance degra-
dation of pneumatic equipment. A filter
or filter regulator capable of removing
particles 40 microns in diameter should
suffice for most applications. Use of
suitable filtration equipment and the es-
tablishment of a maintenance cycle to
monitor its operation is recommended.
Supply pressure must be clean, dry air or noncorrosive
gas that meets the requirements of ISA Standard
S7.3-1975 (R1981). Use a suitable supply pressure
regulator to reduce the supply pressure source to the
normal operating supply pressure shown in table 1-4.
Connect supply pressure to the SUPPLY connection
on the bottom of the case, shown in figure 2-5.
Remote Set Point (suffix letter M)
Pressure Connection
If the controller has remote set point (suffix letter M),
connect the remote set point pressure to the top of the
controller case at the location shown in figure 2-5. Use
clean dry air or noncorrosive gas. Use a 3 to 15 psig
(0.2 to 1.0 bar) remote set point pressure range for a 3
to 15 psig (0.2 to 1.0 bar) controller output signal
range or a 6 to 30 psig (0.4 to 2.0 bar) remote set
point pressure range for a 6 to 30 psig (0.4 to 2.0 bar)
controller output signal range. If pressure is supplied
to the remote set point connection with a regulator, a
small bleed orifice should be placed between the regu-
lator and remote set point connection to prevent pres-
sure variations due to regulator lock-up.
4194A, B, and C Series
46A9765-A
A3001 / IL
Figure 2-5. Location of Connections

Vent

WARNING
If a flammable, toxic, or reactive gas is
to be used as the supply pressure me-
dium, personal injury or property dam-
age could result from fire or explosion
of accumulated gas or from contact with
toxic, or reactive gas. The controller
case and cover assembly do not form a
gas-tight seal, and when the assembly
is enclosed, a remote vent line, ade-
quate ventilation, and necessary safety
measures should be used. However, a
remote vent pipe alone cannot be relied
upon to remove all hazardous gas. Vent
line piping should comply with local
and regional codes and should be as
short as possible with adequate inside
diameter and few bends to reduce case
pressure buildup.
CAUTION
When installing a remote vent pipe, take
care not to over-tighten the pipe in the
vent connection. Excessive torque will
damage the threads in the connection.
If a remote vent is required, the vent line must be as
short as possible with a minimum number of bends
and elbows. Vent line piping should have a minimum
inside diameter of 3/4 inches (19 mm) for runs up to
20 feet (6.1 meters) and a minimum inside diameter of
1 inch (25 mm) for runs from 20 to 100 feet (6.1 to
30.5 meters).
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