ITT BARTON 763A User manual
BARTON MODEL 763A
GAGE PRESSURE TRANSMITTER
User Manual
Part No. 9A-C10861, Rev. 03
July 2010
Contents
Safety............................................................................................................ 2
Section 1—Introduction................................................................................. 3
General ......................................................................................................... 3
Product Description....................................................................................... 3
Gage Pressure Transducer Assembly....................................................... 3
Electronic Transmitter................................................................................ 3
Power Supply ............................................................................................ 3
............................................................................................... 4
Performance.............................................................................................. 4
Application................................................................................................. 5
Storage ......................................................................................................... 6
Section 2—Theory of Operation.................................................................... 7
Basic Components........................................................................................ 7
Gage Pressure Sensing Element.............................................................. 7
Electronic Transmitter................................................................................ 7
Basic Operation ............................................................................................ 7
Reverse Polarity Protection....................................................................... 7
Regulator................................................................................................... 9
Strain Gage Bridge Network...................................................................... 9
.......................................................................................... 9
........................................................................................ 9
Temperature Compensation.......................................................................... 9
Section 3—Installation and Operation.........................................................11
Unpacking/Inspection...................................................................................11
Pre-Operating Instructions...........................................................................11
Mounting ......................................................................................................11
Vibration ...................................................................................................11
Piping.......................................................................................................... 12
Distance .................................................................................................. 12
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Safety
Before installing this product, become familiar with the installation instruc-
tions presented in Section 3 and all safety notes throughout.
!WARNING:This symbol information about practices or circum-
stances that can lead to personal injury or death, property damage, or
economic loss.
CAUTION: Indicates actions or procedures which if not performed correctly
may lead to personal injury or incorrect function of the instrument
or connected equipment.
IMPORTANT: Indicates actions or procedures which may affect instrument operation or
may lead to an instrument response that is not planned.
Slope ....................................................................................................... 12
Process Temperature .............................................................................. 12
Pulsation.................................................................................................. 12
Leakage................................................................................................... 12
Manifolding.................................................................................................. 13
Electrical Connections ................................................................................ 13
Load and Line Resistance Calculations .................................................. 14
EMI/RFI Shielding....................................................................................... 15
Initial Calibration Adjustments..................................................................... 16
Calibration Check.................................................................................... 16
Startup Procedure ................................................................................... 18
Shutdown Procedure............................................................................... 18
Section 4—Maintenance .............................................................................. 19
General Field and Periodic Maintenance.................................................... 19
Periodic Calibration..................................................................................... 19
Transmitter Cover Removal ........................................................................ 21
Transmitter Cover Reinstallation ............................................................. 21
Operation of the EGS Quick Disconnect Connector Assembly................... 22
Leadwire/Connector Replacement.............................................................. 23
Removal of the EGS Quick Disconnect Connector Assembly................. 23
Installation of the EGS Quick Disconnect Connector Assembly.............. 23
Removal of the Barton Style Connector Assembly.................................. 24
Installation of the Barton Style Connector Assembly............................... 24
Troubleshooting .......................................................................................... 26
Section 5—Assembly Drawing and Parts List........................................... 27
Section 6—Dimensional Drawings ............................................................. 29
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Model 763A Gage Pressure Transmitter Section 1
Section 1—Introduction
General
The Model 763A Gage Pressure Transmitter provides a 4-20 mA or 10-50 mA
proportional-to-gage-pressure signal for transmission to remote receiving,
control, or readout devices.
The electronic components of the 763A are housed in a pressure-sealed enclo-
sure. The instruments are designed to operate beyond their normal operating
-
ment of a nuclear power plant under adverse accident and post-accident
conditions. These adverse environments include severe changes in ambient
pressure, temperature and humidity, seismic events, and radiation exposure.
Product Description
Gage Pressure Transducer Assembly
The pressure-sensing element is a C-type Bourdon tube that actuates the elec-
tronic transmitter circuit. The pressure elements are available in Haynes Alloy
#25, which is compatible with most process media requirements and available
in ranges between 0-300 psig and 0-3,600 psig.
!WARNING: Do not tamper with the Bourdon tube inside the enclosure or
the delicate wires connected to it (Figure 3.4, page 16). Improper handling
can damage connections and cause the transmitter to be inoperable.
Electronic Transmitter
The electronic transmitter supplies either a 4-20 mA or a 10-50 mA direct
current output signal that is proportional to the gage pressure sensed by the
Bourdon tube. The output signal is transmitted over a two-wire transmission
line to remote receiving devices.
Power Supply
A regulated direct current (DC) power supply is required to operate the trans-
mitting loop.
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Section 1 Model 763A Gage Pressure Transmitter
Performance
Available Spans.............................. 0-300 to 0-3,600 psig
Output............................................. 4-20 mA or 10-50 mA
Reference Accuracy*...................... ±0.5% of factory calibrated span, including the
effects of conformance (non-linearity), deadband,
hysteresis, and repeatability
Adjustability ....................................
without affecting normal or accident condition perfor-
up to 30% suppression. Zero or Span adjustments
beyond ±5% affect normal and accident condition
performance.Calibration is by the end-point method
with zero and full scale outputs held to ±0.05% of
true.
Sensitivity*...................................... ±0.01% of factory calibrated span
Power Requirements...................... 15 VDC plus 2 VDC per 100 Ohm load to 53 VDC
maximum (4-20 mA)
15 VDC plus 5 VDC per 100 Ohm load to 53 VDC
maximum (10-50 mA)
Load Range
(includes line and receiver)............. 50 Ohms per volt above 15 VDC (4-20 mA)
20 Ohms per volt above 15 VDC (10-50 mA)
Load Effect*.................................... < ±0.05% of factory calibrated span per 100 Ohm
change (4- 20 mA)
< ±0.1% of factory calibrated span per 100 Ohm
change (10-50 mA)
Power Supply Effect*...................... < ±0.025% of factory calibrated span per 1 Volt
change (4-20 mA)
< ±0.05% of factory calibrated span per 1 Volt
change (10-50 mA)
Noise*............................................. < 0.25% peak-to-peak of factory calibrated span
Zero Elevation ................................ Factory adjusted to 14.7 psig
Thermal Effect* (combined
effect on zero and span)................. < ±1.0% of factory calibrated span per 100°F change
from +40°F to +150°F
< ±1.5% of factory calibrated span per 100°F change
from +150°F to +320°F
Radiation*....................................... ±10.0% error for exposures to 2 x 108Rads TID
Gamma
±5.0% error for exposures to 5 x 107Rads TID
Gamma
Seismic:
During Event* ............................. < ±5.0% error (0-300 to 0-3,600 psig spans)
After Event* ................................ < 1.5% error (0-300 to 0-500 psig spans)
< ±0.5% error (0-500 to 0-3,600 psig spans)
LOCA Performance*.......................
(420°F)
< ±10.0% error thereafter to the conclusion of the
LOCA test, as performed per Document No.
9A-CR3-763-6.
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Model 763A Gage Pressure Transmitter Section 1
The LOCA errors include the cumulative effects of
thermal, mechanical, radiation, and seismic aging,
as performed per Document No. 9A-CR3-763-6.
Long Term Drift*.............................. ±1.0% of factory calibrated span per year, cumula-
tive
Time Response .............................. < 180 msec. to reach 50% for 10% to 90% step
function
Maximum Overpressure ................. 150% of factory calibrated span without damage
Process Connection ....................... 1/2" NPT (female)
Electrical Interface.......................... 2-wire (16 AWG) pigtail (20' long)
Weight ............................................ 11 pounds
IMPORTANT: The 763A transmitter has no integral electronic interference suppression
features. If an instrument is to be installed in an area containing EMI/RFI
sources and this interference cannot be tolerated, take precautions to
protect the transmitter signal. See also EMI/RFI Shielding, page 15.
Application
The Model 763 Gage Pressure Transmitter was subjected to IEEE 323-
functional service in a harsh environment (LOCA/MSLB). Subsequent to the
-
-
sembly, using a Bourdon tube/strain gage and connecting wire assembly, has
identical to the Model 763, based on additional analysis.
The service conditions associated with the Model 763A transmitter nuclear
(accelerated aging for
1,830 hours at 257°F)..................... 100 years at normal conditions of 104°F
60 years at normal conditions of 113°F
40 years at normal conditions of 122°F
26 years at normal conditions of 131°F
11 years at normal conditions of 140°F
Radiation Exposure ........................ 200 x 106Rads (TID Gamma)
DBE Environment........................... Two 10-second temperature ramps to 486°F maxi-
mum; 24 hour duration chemical spray exposure;
15 day total exposure to saturated steam at 250°F
minimum
Long Term
Severe Environment....................... 85 days at 200°F and 95% RH
.................... OBE @ 9.0 G (series of 5)
SSE @ 12.5 G
5% critical damping
no resonance in frequencies below 75 Hz
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Section 1 Model 763A Gage Pressure Transmitter
Mechanical Aging ........................... 500,000 pressure cycles during accelerated aging;
Cycled electrically to induce stress during acceler-
ated aging;
Vibration cycling using 0.2 G sweeps over the 1-100
Hz range @ 1.0 octave/min.
Storage
Storage per ANSI N45.2.2-1978 Level B @ 70°F (20°C) ±20°F (±11°C) in
factory-sealed package for 2.5 years maximum will not affect installed service
life.
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Model 763A Gage Pressure Transmitter Section 2
Section 2—Theory of Operation
Basic Components
Gage Pressure Sensing Element
The C-type Bourdon tube is an arc-shaped metal tube that is elliptical in
cross-section and sealed at one end. The opposite end, which is open, is at-
tached to the pressure source. Pressure applied inside the tube affects its shape
and actuates the sensing element.
Electronic Transmitter
The 763A uses a wire (larger gage than that used in the Model 763 transmit-
ter) that is welded to the Bourdon tube and cantilever beam. Increased inter-
nal pressure applied to the Bourdon tube tends to straighten the tube, which in
turn bends the cantilever beam proportionally. Motion of the free end of the
beam applies tension to one gage, increasing its resistance, and compression
to the other, decreasing its resistance. The two gages are connected to form
two active arms of a bridge circuit. The bridge output signal is conditioned
and converted to a 4-20 mA or 10-50 mA output signal by the transmitter
electronics.
Basic Operation
The electronic transmitter is basically a loop current regulating device, where
loop current is controlled by an input of mechanical force or motion. Figure
2.1, page 8
the electrical currents. As shown, the transmitter, power supply, and load (line
plus receiving device) are connected in series.
The current from the power supply enters the transmitter, passes through the
reverse polarity protecting diode, then divides into two separate paths. The
The remainder of the current passes through the electronic regulator, where it
divides into two paths, then passes through the bridge circuit and the voltage
through the load and back to the power supply.
Reverse Polarity Protection
Reverse input polarity protection is provided by the forward-conducting
diode. In the event the polarity of the input is reversed, the diode blocks the
input and prevents the reversed input power from damaging the electronic
circuit components.
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Section 2 Model 763A Gage Pressure Transmitter
Figure 2.1—Operational block diagram
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Model 763A Gage Pressure Transmitter Section 2
Regulator
This stage of the circuit regulates the portion of the loop current that is not
Strain Gage Bridge Network
The strain gage bridge network consists of two silicon piezo-resistive strain
sensors, the zero adjusting potentiometer, bridge completion resistors, and the
temperature compensation components.
current. The amount of current is precisely regulated with the feedback net-
work to be proportional to the bridge output.
Temperature Compensation
The 763A is temperature compensated at the factory. Only those repairs
IMPORTANT Combined zero and/or span changes more than ±5% of the factory
calibration can adversely impact transmitter performance. The transmitter
performance may be decreased in direct proportion to the changes to the
factory calibration. If the combined zero and/or span changes represent
a change in the factory calibration by a factor of 2, the transmitter perfor-
mance may be decreased by a factor of 2.
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Model 763A Gage Pressure Transmitter Section 3
Section 3—Installation and Operation
!WARNING: Failure to follow instructions for removing the transmitter
cover may damage the transmitter cover and case. This could result in
a serious degradation of transmitter performance during design basis
events, resulting in a potential degradation of safety systems. To avoid
the potential for equipment degradation, see Transmitter Cover Removal
on page 21.
Unpacking/Inspection
The instrument should be inspected at the time of unpacking to detect any
damage that may have occurred during shipment.
IMPORTANT: The unit was checked for accuracy at the factory. Do not change any of
the settings during examination or accuracy will be affected.
contamination. This bag should be removed only in a clean area.
Pre-Operating Instructions
The following steps must be performed at the time of installation to ensure
that the instrument will perform to its original calibration.
1. Verify that the transmitter is mounted in an approximately level plane
(see Mounting below).
2. Verify that the transmitter is properly connected to the pressure source
(see Piping, page 12).
3. Verify that electrical connections are in accordance with the schematic
diagram (see Electrical Connections, page 13).
4. Perform the initial calibration adjustments (see Initial Calibration Adjust-
ments, page 15).
Mounting
Mount the instrument on wall or rack with four 5/16" (8mm) bolts, Grade 5
or better, and torque to 10-20 ft-lb. Mounting structures shall be designed to
process tubing and conduit shall be supported by the same mounting as the in-
strument base to minimize relative motion of the instrument and connections.
Vibration
Minimize vibration by mounting the instrument on a secure support.
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Section 3 Model 763A Gage Pressure Transmitter
Piping
Pipe the instrument into the system in accordance with the following guide-
lines. Figure 3.1 shows a typical installation for liquid service. The practices
described in this section should be followed for all instrument piping.
Distance
The distance between the primary device and the instrument should be as
short as possible.
Figure 3.1—Typical installation (liquid service)
Slope
Slope all piping at least one inch per linear foot to prevent liquid or gas en-
trapment in the lines or the instrument.
• Slope all piping downward from the transmitter when used in gas instal-
lations to prevent liquid entrapment.
• Slope all piping upward from the transmitter when used in liquid applica-
tions to prevent gas entrapment.
!WARNING: Take special precautions to prevent hydrogen from contacting
the Bourdon tube. Hydrogen embrittlement of the metal may result.
Process Temperature
If the process temperature exceeds 135°F, provide a minimum of 1-foot of un-
insulated pipe between the instrument and the primary device for each 100°F
above 135°F.
Pulsation
Minimize pulsation. Severe pulsation will affect the instrument's performance.
Leakage
Prevent leakage by using a suitable sealing compound on all joints. Measure-
ment errors can be caused by leaks in the piping.
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Model 763A Gage Pressure Transmitter Section 3
Manifolding
page 12, is recom-
mended for shutting off the sensing lines while removing or calibrating the
instrument.
Electrical Connections
!WARNING: Failure to properly calculate power supply DC output voltage
may resultin inaccurate transmitter readings, possiblyleading to safety
system performance degradation during design basis events. To avoid
equipment inaccuracy hazards, follow the examples and tables provided
in this section for determining the proper power supply DC output voltage.
Field wiring connections for the transmitter are presented in Figure 3.2. If the
transmitter is equipped with an EGS Quick Disconnect connector assembly,
make sure the two halves of the connector are secured with the bayonet ring.
See Operation of the EGS Quick Disconnect Connector Assembly, page 22, for
details.
It is important that the total loop resistance be less than the maximum cal-
culated resistance value and greater than or equal to the minimum resistance
value for proper operation under post-accident conditions. See Figure 3.3,
page 14, for reference.
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Section 3 Model 763A Gage Pressure Transmitter
Figure 3.3—Power supply and loop resistance
Load and Line Resistance Calculations
Use the following method to calculate values of load and line resistance:
Example 1: (Maximum loop resistance for 10-50 mA system):
VDC = 53 Vdc TVDC = 15 Vdc
IDC = 50 mA RT= = 760 Ohms
0.05
53-15
Example 2: (Maximum loop resistance for 4-20 mA system):
VDC = 53 Vdc TVDC = 15 Vdc
IDC = 20 mA RT= = 1,900 Ohms
0.02
53-15
Example 3: (Calculation to determine maximum loop resistance with
power supply ≥30.5 Vdc, but ≤ 53 Vdc for 10-50 mA systems):
VDC = 40 Vdc TVDC = 30.5 Vdc
IDC = 50 mA RT= = 190 Ohms
0.05
40-30.5
Transmitter Current = IDC (20 mA or 50 mA)
RT= VDC - TVDC
IDC
Total Loop Resistance (RT) = RLine + RLoad + RExt
Power Supply Voltage = VDC (53 V max. for 4-20 mA or 10-50 mA Systems)
Maximum Transmitter Voltage = TVDC (15 V for both 4-20 mA and 10-50 mA Systems)
Minimum Transmitter Voltage = TVDC (30.5 V for 10-50 mA Systems)
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Model 763A Gage Pressure Transmitter Section 3
Minimum loop resistance is determined based on maximum power supply
voltage, maximum transmitter current, and maximum transmitter voltage.
Example 4: (Minimum loop resistance for 10-50 mA system):
VDC = 53 Vdc TVDC = 30.5 Vdc
IDC = 50 mA RT= = 450 Ohms
0.05
53-30.5
For 10-50 mA systems, if RLoad = 200 Ohms (Example 1, loop resistance and
Example 4, minimum loop resistance), then RExt + RLine must be ≥ 250 Ohms,
but ≤ 560 Ohms to satisfy both the maximum and minimum loop resistance
values.
For 4-20 mA systems, maximum loop resistance is determined using Example
2. No minimum loop resistance is required with a 53 Vdc power supply.
Care must be exercised when calculating the power supply output voltage. A
e
to ensure the minimum required voltage at the transmitter. Use the actual
value when available; otherwise, use “worst case” value.
Use Figure 3.3 as a reference to determine if the maximum calculated value
of RT= RLine + RLoad + RExt is correct.
EMI/RFI Shielding
IMPORTANT: The 763A transmitter has no integral electronic interference suppression
features. If an instrument is to be installed in an area containing EMI/RFI
sources and this interference cannot be tolerated, take precautions to
protect the transmitter signal.
The following precautions are recommended to limit EMI/RFI interference:
1. Run signal wires in solid conduit or use high quality shielded cable to
connect the transmitter to the power equipment.
2. The transmitter leads should be housed in solid conduit up to the junction
box where the shielded cable is connected to the leads.
3. Ground the electronic transmitter, junction box (including the cover),
conduit, and cable shield.
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Section 3 Model 763A Gage Pressure Transmitter
Initial Calibration Adjustments
If a transmitter is installed after an extended period of storage, a calibration
test should be performed before operating the transmitter to ensure correct
performance.
Accuracy of the test equipment used for the calibration test should be ap-
proximately four times the accuracy of the instrument under test. See Table
4.1, page 19, for general requirements.
IMPORTANT: If there are no calibration access plugs in the cover, the cover must be
removed to adjust calibration. See Transmitter Cover Removal, page 21,
for instructions.
!WARNING: Do not tamper with the Bourdon tube inside the enclosure
or the delicate wires connected to it (Figure 3.4). Improper handling can
damage connections and cause the transmitter to be inoperable.
WARNING:
Do not handle copper wires
Figure 3.4—Bourdon tube wiring (do not handle)
Calibration Check
The transmitter should be tested at minimum, maximum and 50% calibrated
range pressures for at least three cycles.
To test the transmitter calibration, perform the following steps:
1. Remove the calibration access plugs from the transmitter cover using a
socket or a wrench.
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Model 763A Gage Pressure Transmitter Section 3
2. Connect the electrical readout device to the transmitter as shown in Fig-
ure 3.5 for either current or voltage readout. If the transmitter is equipped
to an EGS Quick Disconnect connector assembly, secure the two mating
connectors with the bayonet ring (see page 22 for details).
3. With minimum calibration pressure applied, check the output signal.
Figure 3.5—Electrical connections for calibration
Table 3.1 presents the transmitter output values in current or voltage,
along with the associated tolerance, for both the 4-20 mA and 10-50 mA
variations. If the output signal is not the required reading, adjust the zero
control potentiometer in the compensating direction.
Table 3.1—Calibration Checkpoints
Applied Calibration
Pressure Checkpoint
(% of Full Scale)
Output*
4-20 mA Transmitter** 10-50 mA Transmitter***
Current
(±0.08 mA)
Voltage
(±0.04 Vdc)
Current
(±0.2 mA)
Voltage
(±0.04 Vdc)
0% 4 mA 2 Vdc 10 mA 2 Vdc
25% 8 mA 4 Vdc 20 mA 4 Vdc
50% 12 mA 6 Vdc 30 mA 6 Vdc
75% 16 mA 8 Vdc 40 mA 8 Vdc
100% 20 mA 10 Vdc 50 mA 10 Vdc
*This value includes the effects of conformance (non-linearity), deadband, hysteresis, and repeatability.
**This value was obtained using a 500-Ohm load resistor.
***This value was obtained using a 200-Ohm load resistor.
4. Apply calibration pressure corresponding to maximum output. If the
output signal is not the required reading per Table 3.1, adjust the span
control potentiometer in the compensating direction.
5. Zero and span controls have a minimum of interaction when adjusted;
however, steps 3 and 4 may be repeated as necessary to obtain desired
accuracy.
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Section 3 Model 763A Gage Pressure Transmitter
6. Apply 50% calibration pressure. Check that the output is within Table 3.1
7. If the proper output is not obtained in step 6, recalibrate according to the
calibration procedure on page 19 or return the transmitter to the factory.
8. Replace the calibration access plugs as follows (or if the cover has no
calibration access plugs and was removed, see page 21 for instructions on
replacing the cover).
a. Replacement of the calibration plug O-rings is recommended (coat
with a small amount of silicone grease). If the O-rings cannot be
replaced, inspect the ring surface to verify that the ring surfaces have
no damage and coat them with a small amount of silicone grease
before reinstalling.
b. Install the calibration plugs.
c. Tighten the plugs until they are snug (no applicable torque values).
IMPORTANT: The plugs should be tightened only to prevent loosening due to vibration
without interfering with zero and span potentiometer adjustments.
Startup Procedure
To operate the transmitter, perform the following steps. See Figure 3.1, page 12,
for valve locations.
1. Close the transmitter shut-off valves.
2. Close the transmitter drain valves and calibration connection valves.
3. Open the main block valves at the process connections.
4. Slowly open the transmitter shut-off valves.
5. Apply electrical power to the transmitter loop.
Shutdown Procedure
To shut down operations, perform the following steps. See Figure 3.1, page 12,
for valve locations.
1. Remove electrical power from the transmitter loop.
2. Close the transmitter shut-off valves.
3. Close the main block valves at the process connections.
4. Open the transmitter drain valves and remove all pressure from the unit.
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Model 763A Gage Pressure Transmitter Section 4
Section 4—Maintenance
General Field and Periodic Maintenance
The electronic transmitteris basically maintenance-free and does not require a
routine preventative maintenance program other than periodic calibration checks.
!WARNING: Except for replacement of O-rings, fasteners, and connector
assemblies, no repair or component replacement on the Model 763A
is authorized. Unauthorized repairs void any to
reports for design basis event performance.
WARNING: Do not tamper with the Bourdon tube inside the enclosure or
the delicate wires connected to it (Figure 3.4, page 16). Improper handling
can damage connections and cause the transmitter to be inoperable.
Periodic Calibration
Transmitter calibration is recommended at periodic intervals, determined
primarily by the usage of the transmitter, historical performance, the desired
accuracy of the output signal, or indications that the instrument may be out of
calibration.
A calibration should consist of at least nine checkpoints from minimum to full
scale calibrated pressure and back to minimum. For optimum results, the test
equipment should meet the requirements noted in Table 4.1.
Table 4.1—Calibration Equipment
Equipment Requirements
Digital Multimeter ±0.05% precision (minimum)
Power Supply 15-55 Vdc, 60 mA minimum, regulation 3%, ripple 1%
Precision Load Resistor (if
voltage measurement of
output is made)
200 Ohm, ±0.05%, 1W (10-50 mA Transmitter)
500 Ohm, ±0.05%, 1W (4-20 mA Transmitter)
Pressure Source To provide zero to full scale pressure (Accuracy: ±0.05%)
Milliamp Meter To provide 0-50 mA minimum (Accuracy: ±0.05%)
To check for calibration accuracy, perform the following steps.
1. Shut down the transmitter as follows.
a. Remove electrical power from the transmitter loop.
b. Close the transmitter shut-off valves.
c. Close the main block valves at the process connections.
d. Open the transmitter drain valves and remove all pressurefrom the
unit.
2. Remove the calibration access plugs from the transmitter cover using a
socket or a wrench.
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Section 4 Model 763A Gage Pressure Transmitter
IMPORTANT: If there are no calibration access plugs in the cover, the cover must be
removed to adjust calibration (see Transmitter Cover Removal, page 21).
3. Connect the electrical readout device to the transmitter as shown in
Figure 3.5, page 17 for either current or voltage readout. If the transmitter
is equipped to an EGS Quick Disconnect connector assembly, secure the
two mating connectors with the bayonet ring (see page 22 for details).
4. With minimum calibration pressure applied, check the output signal.
Table 4.2 presents the transmitter output values in current or voltage,
along with the associated tolerance, for both the 4-20 mA and 10-50 mA
variations.
5. If the output signal is not the required reading, adjust the zero control
potentiometer in the compensating direction.
Table 4.2—Calibration Checkpoints
Applied Calibration
Pressure Checkpoint
(% of Full Scale)
Output*
4-20 mA Transmitter** 10-50 mA Transmitter***
Current
(±0.08 mA)
Voltage
(±0.04 Vdc)
Current
(±0.2 mA)
Voltage
(±0.04 Vdc)
0% 4 mA 2 Vdc 10 mA 2 Vdc
25% 8 mA 4 Vdc 20 mA 4 Vdc
50% 12 mA 6 Vdc 30 mA 6 Vdc
75% 16 mA 8 Vdc 40 mA 8 Vdc
100% 20 mA 10 Vdc 50 mA 10 Vdc
*This value includes the effects of conformance (non-linearity), deadband, hysteresis, and repeatability.
**This value was obtained using a 500-Ohm load resistor.
***This value was obtained using a 200-Ohm load resistor.
6. Repeat steps 4 and 5 at eight or more checkpoints (pressures) from
minimum to full-scale calibrated pressure and back to minimum pressure.
-
ments to zero and span potentiometers as required.
7. Replace the calibration access plugs as follows (or if the cover has no
calibration access plugs and was removed, see page 21 for instructions on
replacing the cover).
a. Replacement of the calibration plug O-rings is recommended (coat
with a small amount of silicone grease). If the O-rings cannot be
replaced, verify that the ring surfaces have no damage and coat them
with a small amount of silicone grease before reinstalling.
b. Install the calibration plugs.
c. Tighten the plugs until they are snug (no applicable torque values).
IMPORTANT: The plugs should be tightened only to prevent loosening due to vibration
without interfering with zero and span potentiometer adjustments.
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