Ashcroft KX - Flush Mount Pressure Transmitter - Manual

Mounting
Although the unit can withstand normal vi-
bration without damage or significant output
effects, it is always good practice to mount
the transducer where there is minimum
vibration.
Power Supply
The supply voltage for the 1-5 and
1-6 Vdc output transducers must be within
the range of 10 to 36 Vdc. The maximum
supply voltage for a 4-20mA current output
transducer is 36 Vdc while the minimum
supply voltage is dependent upon the loop
resistance of the circuit. The figure below
shows the minimum supply voltage (V
min
)
required for a given loop resistance (R
LOOP
).
Noise
For minimum noise susceptibility, avoid
running the transducer's cable in a conduit
that contains high current ac power cables.
Where possible avoid running the cable
near inductive equipment.
Shield Wiring
Connect the braided shield to the guard
terminal on the reading instrument (meter,
etc.) if available or to ground or to the power
supply negative terminal.
Adjustment Potentiometers
The zero and span pots are accessible
through the top of the case. Loosen the col-
lar and separate the top carefully. The zero
pot is marked with a white dot.
Vent Tube
The cable will have a clear Teflon vent tube
that's required at pressure below 500 psi to
provide atmospheric reference. The open
end should be placed in a dry area.
V
min
= 10V+ (.022A x R
L
)
R
L
= R
S
+ R
W
R
L
= Loop Resistance (ohms)
R
S
= Sense Resistance (ohms)
R
W
= Wire Resistance (ohms)
1000
750
500
250
0
0 36 20 10
1182
30
Load Limitations 4-20mA Output Only
(R
LOO P
)
OPERATING
REGION
© 2011 Ashcroft Inc., 250 East Main Street, Stratford, CT 06614, USA • Tel: 203-378-8281, Fax: 203-385-0402 • email: [email protected], www.ashcroft.com.
All specifications subject to change without notice. All sales subject to standard terms and conditions of sale. I&M011-10156 (250-A152) Rev. A 5/11
MODEL KX THIN FILM
PRESSURE TRANSDUCER
INSTRUCTION SHEET
WARNING! READ
BEFORE INSTALLATION
m m
1. GENERAL:
A failure resulting in injury or damage
may be caused by excessive overpres-
sure, excessive vibration or pressure
pulsation, excessive instrument tempera-
ture, corrosion of the pressure containing
parts, or other misuse. Consult Ashcroft
Inc., Stratford, Connecticut, USA before
installing if there are any questions or
concerns.
2. OVERPRESSURE:
Pressure spikes in excess of the rated
overpressure capability of the transducer
may cause irreversible electrical and/
or mechanical damage to the pressure
measuring and containing elements.
Fluid hammer and surges can destroy
any pressure transducer and must always
be avoided. A pressure snubber should
be installed to eliminate the damaging
hammer effects. Fluid hammer occurs
when a liquid flow is suddenly stopped,
as with quick closing solenoid valves.
Surges occur when flow is suddenly be-
gun, as when a pump is turned on at full
power or a valve is quickly opened.
Liquid surges are particularly damag-
ing to pressure transducers if the pipe
is originally empty. To avoid damaging
surges, fluid lines should remain full (if
possible), pumps should be brought up to
power slowly, and valves opened slowly.
To avoid damage from both fluid hammer
and surges, a surge chamber should be
installed.
Symptoms of fluid hammer and surge's
damaging effects:
• Pressure transducer exhibits an output
at zero pressure (large zero offset).
• Pressure transducer output remains
constant regardless of pressure
• In severe cases, there will be no output.
FREEZING:
Prohibit freezing of media in pressure
port. Unit should be drained (mount in
vertical position with electrical termination
upward) to prevent possible overpressure
damage from frozen media.
3. STATIC ELECTRICAL CHARGES:
Any electrical device may be susceptible
to damage when exposed to static elec-
trical charges. To avoid damage to the
transducer observe the following:
• Ground the body of the transducer
BEFORE making any electrical
connections.
• When disconnecting, remove the
ground LAST!
Note: The shield and drain wire in the
cable (if supplied) is not connected to the
transducer body, and is not a suitable
ground.