Ametek A-DS1B User manual

MODEL HPT 100 SERIES
HIGH PURITY PRESSURE
TRANSMITTER
INSTRUCTIONS FOR INSTALLATION,
OPERATION AND CALIBRATION
U.S GAUGE DIVISON
PMT PRODUCTS

HPT 100 SERIES
WARRANTY POLICY
Ametek warrants these products for a period of three years from the date of shipment or
date of registration if the card is submitted and that all products manufactured by the
seller are free from defects of material and workmanship when used within the service,
range, and purpose for which they were manufactured. Seller will, at its option, repair,
replace, or refund the purchase price of parts found by Seller to be defective in material or
workmanship provided that written notice of such defect requesting instructions for
repair, replacement, or refund is received by Seller at the address below within the
warranty period and provided that any instructions thereafter given by Seller are complied
with.
This warranty shall not apply (i) to the performance of any system of which Seller's
products are a component part, (ii) to deterioration by corrosion or any cause of failure
other than defect of material or workmanship, or (iii) to any of Seller's products or parts
thereof which have been tampered with or altered or repaired by anyone except Seller or
someone authorized by Seller, or subjected to misuse, neglect, abuse or improper. use or
misapplication such as breakage by negligence, accident, vandalism, the elements, shock,
vibration, or exposure to any other service, range, or environment of greater severity than
that for which the products were designed.
SELLER MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED.
INCLUDING WITHOUT LIMITATION ANY WARRANTIES OF FITNESS OR OF
MERCHANTABILITY WITH RESPECT TO ITS PRODUCTS, OR ANY PART
THEREOF, OTHER THAN AS EXPRESSLY SET FORTH ABOVE. NOR SHALL
SELLER HAVE INCURRED ANY OTHER OBLIGATIONS OR LIABILITIES OR
BE LIABLE FOR ANY ANTICIPATED OR LOST PROFITS, INCIDENTAL
DAMAGES, CONSEQUENTIAL DAMAGES, TIME CHARGES, OR ANY OTHER
LOSSES INCURRED IN CONNECTION WITH THE PURCHASE,
INSTALLATION, REPAIR, OR OPERATION OF ITS PRODUCTS (INCLUDING
ANY PARTS REPAIRED OR REPLACED).
This warranty does not extend to anyone other than the original Buyer from Seller and
Seller’s agents.

CONTENTS
WARRANTY cover
Seller’s Registration Card ii
INTRODUCTION iii
Safety Summary
SECTION I- SPECIFICATIONS
Model HPT 100 Series Transmitter Model
Number System 1-1
Description 1-2
Specifications 1-2
EMI / RFI Immunity- C.E. Classification 1-4
Safety Approvals 1-5
CE Declaration Of Conformity 1-9
SECTION II - INSTALLATION
Mechanical 2-1
Electrical 2-2
Outdoor 2-6
SECTION III - OPERATION
Principle Of Operation 3-1
SECTION IV - CALIBRATION
Calibration Procedures 4-1
Zero / Span Pot & Diagnostic Shunt Location Diagram 4-2
SECTION V - SERVICE AND PARTS
Factory Service 5-1
Circuit Board Replacement 5-2
Spare Parts 5-3
i

WARRANTY REGISTRATION REPORT
DISTRIBUTOR: DATE:
LOCATION:
CUSTOMER: CONTACT NAME:
ADDRESS: PHONE:
The units listed below have been delivered and the warranty period has begun. A copy of
the invoice is attached.
SERIAL # DESCRIPTION GAS SERVICE FLOW RATE OP. PRESS
ii

_____________________________________________________INTRODUCTION
The HPT 100 is a series of pressure transmitters specifically designed to meet the ultra-clean and
ultra-high stability and reliability requirements of the semiconductor industry. Because most of
the process gases to be measured by the HPT 100 are highly reactive and pose toxic threats to the
facility personnel, the manufacturing tolerances and operating specifications are very strict.
Many of these units will be permanently welded into the gas distribution system, so the design
includes external access to the electronic circuitry by qualified repair personnel and zero and
span pots for field calibration.
All HPT 100 units are labeled with the C.E. mark certifying compliance with European standards
for RFI/EMI immunity.
HPT 100 units with the suffix ‘1’ in the model number are labeled with agency approval from
Canadian Standards Association (CSA) and Laboratoire Central Des Industries Electriques
(LCIE) for Intrinsically Safe and Non-Incendive Systems for operation in hazardous locations.
HPT 100 units with the suffix ‘2’ in the model number are labeled with CSA approval for
operation in Division 2 Locations.
HPT 100 units with the electrical connection suffix “N” or “C” or “P” are rated NEMA 4X
Enclosure by CSA and IP56 Enclosure by LCIE. Electrical Connection Suffix “N” or “C” is
recommended for outdoor use.
SAFETY SUMMARY
This instrument is designed to prevent accidental shock to the operator when properly used.
However, no design can ensure the safety of an instrument improperly installed or used
negligently. Read this manual carefully and completely before operating the instrument. Failure
to read this manual in its entirety could result in damage to the instrument or injury to the
operator. Standard safety precautions must be used during installation and operation. Important
messages located throughout this manual are as follows:
WARNING - Denotes a hazardous procedure or condition which, if ignored, could
result in injury or death to the operator.
CAUTION - Denotes a hazardous procedure or condition which, if ignored, could
result in damage or destruction to the instrument.
IMPORTANT - Denotes a procedure or condition which is essential to the correct
operation of the instrument.
NOTE - Specifies supplementary and perhaps essential information in relation to
a particular procedure or condition.
iii

SECTION I SPECIFICATIONS
100 -------
AGENCY
APPROVAL
1= Intrinsic Safety/
Non-Incendive
2 = Division 2
3 = No Rating
ELECTRICAL
CONNECTION
B= Bendix Type
P= Pigtail
C= Outdoor-1/2" Conduit Adapter
N= Outdoor-10 ft. Pigtail
OUTPUT
1= 4 -20 mA.
2 = 0-5 Vdc
PROCESS
SIZE
4 = 1/4"
6= 3/8"
8= 1/2"
PROCESS
CONNECTION
TYPE
SM =Face Seal Swivel Male
SF = Face Seal Swivel Female
FM = Face Seal Integral Fixed Male
BW = Butt Weld Tube Stub
TS = Swept Path Tee (Pressure Cavilty Type Option "S" only)
PRESSURE
RANGE
0100 = 100 Psi
0250 = 250 Psi
1000 = 1000 Psi
2000 = 2000 Psi
3000 = 3000 Psi
ZERO
REFERENCE
V
= -14.7 Psig
G= 0 Psig/ 0 Bar
A
= Absolute*
PRESSURE
CAVITY
TYPE
F= Flow Through
S= Single-ended
* Absolute Pressure Ranges provided as a vacuum gauge reference
i.e 0-250 Psia provided as -14.7 Psig to 235.3 Psig
pg. 1-1

DESCRIPTION:
The HPT 100F is a flow-through style transmitter
while the HPT 100S is a single-ended or deadleg
style. Each style is available with a variety of tube
stub and face seal connections. Electrical connection
is via either a Bendix® compatible 4 pin connector or
a flying lead pigtail. The small size and light weight
of the HPT 100 eliminates the need for bulky
mounting hardware and mechanical supports.
FUNCTIONAL SPECIFICATIONS:
SERVICE: Liquid, gas or vapor
AVAILABLE RANGES: vac to 100 psig, vac to 250 psig, vac to 1000 psig,
vac to 2000 psig, vac to 3000 psig. Alternate ranges, including
Bar and lower ranges, are available.
OUTPUT: 4-20 mA, 2 wire, current limited with
reverse polarity protection or
0-5 Vdc (Calibrated 0.1- 5.1 Vdc)
POWER SUPPLY: 12 to 30 Vdc
LOOP RESISTANCE (4 - 20 mA.): 900 ohms at 30 Vdc; 0 ohms at 12 Vdc
OUTPUT LOAD (0 - 5 Vdc): > 50K ohms
SPAN/ZERO ADJUSTMENT: +/- 5% of span minimum
TEMPERATURE LIMITS:
COMPENSATED: 0OC to 50OC
OPERATING: -25OC to 85OC
STORAGE: -40OC to 85OC
HUMIDITY: 0-95% RH (pigtail cable) *
0-95% RH (Bendix®type >=500 psig)
0-80% RH (Bendix®type <500 psig)
OVERRANGE: 150% of Full Scale
BURST PRESSURE: 400% of Full Scale
HAZARDOUS LOCATIONS:
INTRINSICALLY SAFE: Class I, Division 1, Groups A, B, C & D, NEMA 4X (IP56)
Approved Barrier Required
DIVISION 2: Class I, Division 2, Groups A, B, C & D, NEMA 4X
Protective Enclosure or Conduit Connection Required
Note: NEMA 4X/IP56 applies to pigtail terminations version only
*(vent through cable to dry environment)
DIELECTRIC ISOLATION: 100V DCpg. 1-2

PERFORMANCE SPECIFICATIONS:
ACCURACY: ±0.25% of FS includes linearity (BFSL), hysteresis and
repeatability
RESPONSE: Time constant of less than 20 milliseconds
STABILITY: ±0.125% of FS per 6 months under reference conditions
TEMPERATURE EFFECTS:
ZERO CHANGE: +/- 1.0% of FS within compensated temperature range*
SPAN CHANGE: +/- 1.0% of FS within compensated temperature range*
* +/- 0.5% of FS for electrical connection options “N” & “C”
ELECTROMAGNETIC CE Marked per EMC Directive: 89/336/EEC, Semi E33-94
COMPATIBILITY:
PHYSICAL SPECIFICATIONS:
SENSING ELEMENT: Metal Thin Film Bridge deposited on Hastelloy® C-22™
diaphragm
WETTED SURFACES: Hastelloy® C-22™ and 316L VAR Stainless Steel
WETTED SURFACE FINISH: Electro-polished to 10 RAmax
HOUSING MATERIAL: 300 Series Stainless Steel
OUTPUT CONNECTOR: Bendix® (PTIH-8-4P) compatible or pigtail (10 ft. standard)
CLEANING/ PACKAGING: Class 100 cleanroom, 18 megaohm D.I. water rinse, double
bagged per Ametek K794442
SHIPPING WEIGHT: 0.78 lbs. (354 g)
LABEL: Includes Ametek logo, pressure range, input and output, date,
serial number, regulatory markings, zero and span pot
identification and diagnostic shunt value.
pg. 1-3

SECTION I EMI/ RFI IMMUNITY
Ametek UHP Transmitter CE Marking
The Model HPT 100 4-20 mA and 0-5Vdc transmitters have been tested and declared as
conforming to the European EMC directive 89/336/EEC.
This allows the transmitter full access to the European market and is identified with a CE
mark on the transmitter body.
The chosen generic immunity standard EN 50082-2 was utilized as a foundation for the
testing program necessary to confirm compliance. This involves operation in an industrial
environment and is acceptable for semiconductor manufacturing.
In addition, by complying with the tests dictated in EN50082-2, compliance with SEMI
specification E33-94 is also achieved. By achieving compliance, the customer is assured
that the transmitter will offer considerable resistance to induced EMI, ESD, fast
transients, and lightning surges.
Proper installation, including use of a shielded cable is required to assure full protection.
Please consult the section on installation to determine how to wire your transmitter.
A Declaration of Conformity is reprinted in this manual and details the tests conducted
during third party laboratory testing.
pg. 1-4

SECTION I SAFETY APPROVALS
Ametek UHP Transmitter Safety Approvals:
The model HPT 100 transmitters with the appropriate suffixes have been declared as
conforming to the following safety classes: (See model code structure section I, pg. 1-1)
Intrinsic Safety/Non-Incendive: Class I, Groups A, B, C, D (Agency Approval Suffix 1)
Division II : Class I, Div 2, Groups A, B, C, D (Agency Approval Suffix 2)
NEMA/IP Rating: Type 4X/IP56 ( Electrical Connection Suffix P, N or C)
Approval has been granted by Canadian Standards Association. In addition to Canadian
approval, CSA is listed as a Nationally Recognized Testing Laboratory (NRTL), which is
accredited by the Occupational Safety and Health Administration (OSHA) under the U.S.
Department of Labor. This allows CSA to Certify electrical products to U.S. Standards.
The CSA/NRTL mark is recognized throughout the U.S. at federal, state and local levels,
and is equivalent to any agency mark in the U.S. with respect to acceptance by regulatory
authorities. The intrinsic safety unit also carries LCIE approval with the EExia symbol,
allowing full recognition in Europe.
Intrinsic Safety/Non-Incendive(CSA): A suitable barrier is required. Either entity or
system approval parameters can be followed to determine which barrier(s) to use.
Consult section on installation instructions (Drawing K750525 for 4 - 20 mA. or
K750531 for 0-5V). Entity parameters: 4-20 mA; Vmax = 28 Volts, Imax = 100 mA,
Ci = 65nf, Li = 40 uH. 0-5V; Vmax = 28 Volts, Imax = 100 mA, Ci = 76nf, Li = 50 uH.
Temperature Code Ratings: 4-20 mA(System Approval); T5 at 40°C max. ambient
or T4 at 85°C max. ambient. 4-20 mA(Entity Approval); T3C at 40°C max. ambient or
T2C at 85°C max. ambient. 0-5V(System Approval); T6 at 40°C max. ambient or T4 at
85°C max. ambient. 0-5(Entity Approval); T3C at 40°C max. ambient or T2C at 85°C.
Only pigtail models with suffixes P, N or C are rated Type 4X.
Intrinsic Safety (LCIE): A suitable barrier is required. The same entity parameters
listed for CSA apply. Temperature Code Ratings: 4-20 mA. or 0-5Vdc: T4 at 40°C
max. ambient or T3 at 85°C max. ambient. The associated apparatus (safety barrier) must
not exceed the following limits: Uo < = 28 V; Io < = 100 mA.; Po < = 0.7 w. When
installing the enclosure, it must be isolated from ground surfaces or shall be at the same
earth potential as the barrier earth ground.
Division 2: Input rated 12-30Vdc for outputs 4-20 mA. or 0-5Vdc. Maximum temperatue
85°C ambient; The HPT 100 models except with Electrical Connection Suffix “C” are
certified as a component for use only in other equipment (gas cabinet, for example) where
the suitability of the combination is to be determined by the authority having jurisdiction.
The intent is to protect the cabling from shorting or opening by use of a suitable
protective enclosure. pg. 1-5

To eliminate the need for a protective enclosure, one may achieve Div 2 compliance by
using a suitable barrier(s) as described in Drawing K750525/K750531. To eliminate the
need for a protective enclosure or suitable barrier and still be Div 2 compliant, the conduit
adapter model (suffix C) along with properly rated and sealed conduit should be used.
Only pigtail models with electrical connection suffixes P, N or C are rated as Type
4X/IP56
For all safety locations, proper wiring and installation is critical. Installation must be
performed by licensed installers, under jurisdiction of local authorities. The safety
approvals are voided by modifications or non factory repairs to the HPT 100.
pg. 1-6

pg. 1-7

pg. 1-8

DECLARATION OF CONFORMITY
(In accordance with EN45014)
We, AMETEK US GAUGE DIVISION
PMT PRODUCTS
820 Pennsylvania Blvd.
Feasterville, PA. USA 19053
declare that the product,
Type of Equipment: Ultra High Purity Pressure Transmitter
Model Number: HPT 100, 4-20 mA Output and 0-5 Vdc Output
Pressure Ranges: All Standard Ranges From Vacuum to 3000 psig
to which this declaration relates is in conformance with the following standards or
other normative documents:
EMC: EN 50082-2 (1995) Generic Immunity, Industrial Environment
EN55011 (1993), No Emissive Sources by Analysis
EN61000-4-2 / IEC 1000-4-2 (1995), ESD, 4KV Contact
ENV 50140, (1993) Radiated Electromagnetic Field: 80-1000
MHz, 80% AM, 1 KHz sine, 10V/m.
ENV 50204, (1995) Radiated Electromagnetic Field, 900 MHz,
Pulse Modulation, 200 Hz 50% Duty cycle, 10V/m.
EN 61000-4-4 / IEC 1000-4-4, (1995) Fast Transient, 1 kV,
2kV on DC/signal line.
EN 61000-4-5 / IEC 1000-4-5 (1995), Surge Immunity, 0.5
kV(4-20 mA.), 1kV(0-5Vdc), normal mode and common mode.
ENV 50141, Conducted Immunity 150KHz to 80 MHz, 10V
following the provision of EMC directive 89/336/EEC.
Ametek U.S. Gauge, PMT Products
820 Pennsylvania Blvd.
Feasterville, PA 19053, USA
215-355-6900 Tel
215-364-9537 Fax
[e-mail] Email www.ametekusg.com Web
European Contact :
AMETEK Precision Instruments Europe GmbH
Rudolf-Diesel-Strasse 16
D-40670 Meerbusch
Germany
Phone: [phone]/ Fax: [phone]
pg. 1-9
ISO9001
ISO9001ISO9001
ISO9001 REGISTERED
MANUFACTURER

SECTION II INSTALLATION
The HPT 100 Series transmitters are packaged in a Class 100 cleanroom environment.
The units are carefully double-bagged with a clean, dry nitrogen environment to maintain
the UHP condition during shipment. Upon receiving the units, check for evidence of
damage to the physical and electrical connectors and to the integrity of the bagging
package. If the bag is torn or other damage is evident, obtain a Return Authorization (RA)
Number from your Ametek representative and return the unit for evaluation.
MAKING MECHANICAL CONNECTIONS:
WARNING - Personnel injury or damage to equipment may result from improper
installation due to the internal pressures of the media. Verify the leak integrity of the
mechanical connections BEFORE applying operating pressures.
IMPORTANT - Assemble and tighten face seal connections according to the fitting
manufacturer’s directions. First hand tighten before wrenching, then apply a maximum
of 1/8 turn past finger tight for metal gaskets and 1/4 turn for soft gaskets.
CAUTION - Do not place torque across the body of the transmitter by gripping the body
on the opposite end of the unit when tightening the nut.
IMPORTANT- Use the proper output signal / power cable for your unit.
MAKING WELDED CONNECTIONS:
IMPORTANT - Disconnect unit from its electrical source during welding installation.
IMPORTANT - When possible, direct internal argon purge flow away from the
transmitter during welding.
pg. 2-1

SECTION II ELECTRICAL
Installation Notes on Ametek UHP 4-20 mA Transmitter
Wiring Notes: Bendix® compatible connector
1. Hookup: The 4-20 mA transmitter utilizes a 2 wire system. Current flowing from a
power supply into Connector Pin A is used to power the transmitter. Current flowing
out of Connector Pin D may be connected to a 4-20 mA input of a loop indicator, for
example, or across a loop resistor. The return from the loop indicator or loop resistor
should be tied to the negative connection of the power supply. It is important to
understand the voltage drop of any loop device added in series with the current flow.
For example, many loop indicators or PLC’s may take up to 5 Vdc each to operate (at
full scale current of 20 mA.). The transmitter should have at least 12 Vdc across
Connector Pin A and Pin D at all times. Thus in this example, with the transmitter
needing 12 Vdc to operate and the loop indicator and PLC each requiring 5 Vdc, the
power supply should be set above 22 Vdc. A 24 Vdc supply is often used when
operating multiple loop devices.
2. Grounding and Shielding: The Bendix® compatible connector pin C may be used to
connect to the transmitter case. For use in high EMI fields, the user may wish to tie a
mating cable shield or drain wire to this pin to provide shielding to the transmitter
case. With some mating connectors, it is not necessary to tie the shield or drain wire
to pin C if the mating cable has a clamp which can be crimped over the drain wire and
the act of mating the two connectors provides shield continuity. A separate wire may
also be tied to pin C to bring the case ground connection to another location. In many
cases, the mating cable shield can be tied to the gas cabinet case, providing an
excellent shield to EMI. In some cases, however, ground loops may prevent this type
of hookup so caution is advised.
pg. 2-2

Installation Notes on Ametek UHP 4-20 mA Transmitter (continued)
Wiring Notes: 4-20 mA. pigtail cable style
1. Hookup: The 4-20 mA transmitter utilizes a 2 wire system. Current flowing from a
power supply into the red lead is used to power the transmitter. Current flowing out
of the black lead may be connected to a 4-20 mA input of a loop indicator, for
example, or across a loop resistor. The return from the loop indicator or loop resistor
should be tied to the negative connection of the power supply. It is important to
understand the voltage drop of any loop device added in series with the current flow.
For example, many loop indicators or PLC’s may take up to 5 Vdc each to operate (at
full scale current of 20 mA.). The transmitter should have at least 12 Vdc across the
red and black leads at all times. Thus in this example, with the transmitter needing 12
Vdc to operate and the loop indicator and PLC each requiring 5 Vdc, the power
supply should be set above 22 Vdc. A 24 Vdc supply is often used when operating
multiple loop devices.
2. Grounding and Shielding: The green lead is a connection to the transmitter case and
may be used as required to provide continuity to the case. For use in high EMI fields,
the user may wish to tie the additional drain wire (this is also tied internally to the
transmitter case) to the gas cabinet case or system earth ground to provide optimal
EMI shielding. With some installations, it may not be desirable to tie the green wire
or drain wire to the gas cabinet case or system earth. Ground loops may prevent this
type of hookup so caution is advised.
White Wire: The white wire is not used in a 4-20 mA configuration.
Wire Color Signal/Exc.
Red +
Black -
White Not Connected
Green Case
Shield Case
pg. 2-3

SECTION II ELECTRICAL
Installation Notes on Ametek UHP 0-5 Vdc Transmitter
Wiring Notes: Bendix® compatible connector (0-5 Vdc)
1. Hookup: The 0-5 Vdc output style transmitter utilizes a 3 wire system. Voltage
applied from a power supply into connector Pin A (Excitation (+)) and connector Pin
D (Excitation (-)) may be used to power the unit. The signal output (0-5 Vdc) is taken
from connector Pin B (Signal (+)) with respect to connector Pin D (Signal -). Note
that connector Pin D is common to both the Voltage input Excitation (-) and Signal
output (Signal (-)). When connecting a load to connector Pin B, remember to connect
this pin to a high impedance amplifier circuit.
2. Grounding and Shielding: The Bendix® compatible connector Pin C may be used to
connect to the transmitter case. For use in high EMI fields, the user may wish to tie a
mating cable shield or drain wire to this pin to provide shielding to the transmitter
case. With some mating connectors, it is not necessary to tie the shield or drain wire
to Pin C if the mating cable has a clamp which can be crimped over the drain wire and
the act of mating the two connectors provides shield continuity. A separate wire may
also be tied to Pin C to bring the case ground connection to another location. In many
cases, the mating cable shield can be tied to the gas cabinet case, providing an
excellent shield to EMI. In some cases, however, ground loops may prevent this type
of hookup so caution is advised.
pg. 2-4

Installation Notes on Ametek UHP 0-5 Vdc Transmitter (Continued)
Wiring Notes: 0-5 Vdc pigtail cable option
1. Hookup: The 0-5 Vdc output style transmitter utilizes a 3 wire system. Voltage
applied from a power supply into the Red Wire (+) and Black Wire (-) must be used
to power the unit. The Signal output (0-5 Vdc) is taken from the White Wire (Signal
(+)) and the Black Wire (Signal (-)). Note that the Black Wire is common to both the
Voltage Input (-) and Signal Output (-). When connecting a load to the White Wire,
remember to connect this signal to a high impedance amplifier circuit.
2. Grounding and Shielding: The green lead is a connection to the transmitter case and
may be used as required to provide continuity to the case. For use in high EMI fields,
the user may wish to tie the additional drain wire (this is also tied internally to the
transmitter case) to the gas cabinet case or system earth ground to provide optimal
EMI shielding. With some installations, it may not be desirable to tie the green wire
or drain wire to the gas cabinet case or system earth. Ground loops may prevent this
type of hookup so caution is advised.
Wire Color Signal/Exc.
Red + Exc.
Black - (Exc./Signal)
White + Signal
Green Case
Shield Case
pg. 2-5

SECTION II____________________________________OUTDOOR
Only certain versions of the HPT 100 are recommended for outdoor locations. Under the
Electrical Connection Suffix on the model code structure in Section I on page 1-1, the
suitable letters are “N” or “C”.
Electrical Connection Suffix “N” or “C” is used when an outdoor location is planned as
the unit is compensated for outdoor temperatures and all seals are checked for leak rate.
Both styles employ a type of pigtail termination.
For Electrical Connection Suffix “N”, when used in a Div 2 location, the use of a
secondary protective enclosure is required(gas cabinet for example). This is to protect the
exposed pigtail cable. An alternative is to use an approved safety barrier.
For Electrical Connection Suffix “C”, when used in a Div 2 location with conduit, the use
of a secondary protective enclosure is not required as the pigtail cable is contained within
the conduit.
In an effort to provide long term operation in a harsh outdoor environment, Ametek has
designed the HPT 100 to resist the introduction of moisture to the internal circuitry. The
use of conformal coating on the circuit boards(outdoor models only) also aids the
rejection of the outside elements. It is essential that the potentiometer access cover be
properly tool tightened after any check or adjustment. Periodic checking of the
potentiometer access cover for a snug fit is recommended. To avoid damage to threading
and seals do not over tighten.
Since the unit is a gauge referenced unit, a path for “breathing” must be maintained. In
the HPT 100 pigtail models, the breathing path is maintained through the pigtail cable.
For this reason it is mandatory to terminate the cable in a dry, temperature stable
environment. It is also essential that the cable remain without any nicks or cuts and that
splicing cable lengths not be utilized. It is further recommended that a slight positive
pressure be applied to the pigtail termination (Z-purge). This method is often used to
keep outdoor gas cabinets dry under any weather condition. A suitable pigtail cable
crimp seal located at the gas cabinet may be used to allow the pigtail to enter a Z-purged
gas cabinet. The slight positive pressure entering the cable will be enough to allow the
transducer to function with any type of weather phenomenon for very long periods. The
pressure must be kept low enough to avoid affecting the measured pressure. A few tenths
of an inch of water pressure is adequate to protect the transducer and small enough not to
significantly affect pressure measurement accuracy.
The use of a Bendix connector outdoors should not be attempted because of the difficulty
of sealing the termination. Further, the low pressure models utilizing the Bendix
connector are vented locally through the transmitter itself and not the electrical
termination.