ASHCROFT GC55 Differential Pressure Transducer Instruction Manual
- June 3, 2024
- ASHCROFT
Table of Contents
GC55 Differential Pressure Transducer
Installation and Maintenance Instructions for GC55 Differential Pressure
Transducer
Version 1.0 5/11
© 2012 Ashcroft Inc. 250 East Main Street, Stratford, CT 06614 USA Tel:
203-378-8281, Fax:
203-385-0402 www.ashcroft.com All sales
subject to standard terms and conditions of sale. I&M011-10158. Rev. D 6/12
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WARNING! READ BEFORE INSTALLATION
1. GENERAL:
A failure resulting in injury or damage may be caused by excessive
overpressure, excessive vibration or pressure pulsation, excessive instrument
temperature, 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 begun, as when a pump is turned on
at full power or a valve is quickly opened.
Liquid surges are particularly damaging 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
electrical 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.
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ConTenTs 1. specifications ………………………………………….. 6 2. Dimension Drawings
……………………………….. 7-8 3. Installation ……………………………………………….. 8 4. Wiring
………………………………………………………. 9 5. noise Prevention………………………………………. 9 6. storage
…………………………………………………….. 9 7. Maintenance ……………………………………………. 9 8. Menu
navigation ………………………………………. 11 9. Function setting Mode ……………………………… 12 10.
switch setting Mode…………………………………. 15 11. switch operation………………………………………. 17
12. Loop Check Mode …………………………………….. 18 13. other Functions ……………………………………….
19 14. Maintenance & Warranty ………………………….. 22
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1. specifications Pressure Range: 75, 100, 150, 250, 300 psid (as noted on
the unit) Proof Pressure*: 2X F.S. Differential Pressure Range (DP):
DP=P1(H)-P2(L); as marked on unit Display Range: Diff. pressure range of 5 to
105%F.S. or display of 1999 to 1999 Power supply: · 4-20ma Output Version:
15-27 Vdc, 80mA · 1-5 Vdc Output Version: 11-27 Vdc, 60mA Display: 31/2 digit
LED (digit height: 10mm) Display accuracy DP : ±(1.0%F.S.+1 digit) P1, P2 :
±(0.5%F.S.+1 digit) Update Time: 0.2 s Media / Wetted Materials: Fluids and
gases compatible with 304SS (sensor housing) and 17-4ph SS (sensor diaphragm)
output: Analog output (4-20mA or 1-5Vdc)**: Accuracy: ± 0.5% FS (Accuracy
includes the effects of Linearity, Hysteresis and Repeatability) Temperature
characteristics DP : Zero ±0.1%F.S./°C : Span ±0.1%F.S./°C P1, P2 : Zero
±0.05%F.S./°C : Span ±0.05%F.S./°C Response Time: 20msec 10.0 sec (by user)
Output Resolution: 0.2% FS Pressure switch output: Type: (2) photo MOS relays,
rated to 40Vdc/200mA Setting Accuacy: ± 1.0% FS Number of Contacts: 2
Hysteresis/Deadband: Variable (by user) Window Comparator: 1%F.S. fixed Delay:
0-2.00s (both ON, OFF) Load resistance: 10k min-500 max. operating
Temperature: 10 to 50°C (14 to 122°F)
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operating humidity range: 10 to 85%(with no condensation)
storage Temperature: 20 to 60°C (4 to 140°F) (non freezing)
Case construction: IP65/NEMA 4 Pressure Connections: 1/8 NPT Female (2) places
enclosure Material: Aluminum Weight: 18 ounces Notes: *Maximum operating
static (line) pressure is the full scale range of the unit ordered/specified.
The operation and features of the GC55 are based upon the use of the two
independent pressure transducers with electronics which provide a different
pressure output based upon the difference in measurement between the two
sensors. **Option selected at time of order. 2. Dimension Drawings
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3. Installation Install in a location where vibration and shock can be
minimized and without direct sunlight on the display in compliance with IP64
environmental rating. · Pressure Port Connections: 1/8 NPT female, 11/2 turns
past hand tight. · Mounting: Remove the GC55 cover, 4 screws, and attach via
through holes, (2) places, 0.20 diameter.
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4. Wiring Terminal strip Designations The terminals are as shown below. Connect power only after checking wiring. After power is turned on, wait at least 15 minutes before performing a zero adjustment or measurement.
Power supply () Power supply () OUT 1 (Switch) OUT 2 (Switch)
output state
COM. (Switch)
Analog output
Applicable wire 16-22 AWG
Cable Gland or 1/2 FNPT Conduit Connection
5. noise Prevention Power supply If noise is present in the power supply /
wires the pressure display can fluctuate and provide incorrect output. Care
should be taken to keep the GC55 power supply wires from high voltage lines
and use a power line with a high noise rejection ratio.
6. storage Store in a location in compliance with the environmnetal rating of
the unit and within 20 to +60C (4 to 140F).Avoid direct exposure of the
display to sunlight
7. Maintenance Although this is a solid state device a twice yearly visual
inspection is recommended along with regular zero adjustment if necessary.
8. Menu navigation Functions PLEASE NOTE: Only the “SEL” function is
available from the case exterior, accesss to all other functions requires the
cover to be removed. Do not use sharp objects to press the keys as this can
puncture the panel. See illustration 1 and illustration 2. External Panel and
Functions (SEL key can be operated externally)
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Illustration (1) Illustration (2)
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8. Menu navigation (cont.) External Panel and Functions (SEL key can be
operated externally)
Illustration (3)
8. Menu navigation (cont.) Internal Panel and Functions (cover removed)
Illustration (4)
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8. Menu navigation (cont.) Pressing the MODE key for 3 seconds displays “—“.
To return to measurement mode from each setting mode, the “—” display will
flash when 3 seconds have passed.
*Note: Zero Adjustment, select P1 and P2 respectively and then use Zero Adjustment, will not function in DP mode.
9. Function setting Mode setup steps Pressing the MODE key for 3 seconds
displays “—“. To return to measurement mode from each setting mode, the “—”
display will flash when 3 seconds have passed. The setting mode is used to
select switch operation, pressure unit, indication scaling, scaling of analog
output, and filter time constant.
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Entering the setting value in function setting mode resets all of the setting values including the switch. Please note that when the reset setting values are out of the display range, they will be adjusted to an upper or lower limit value that can be processed internally.
switch operation Select “Switch Operation Selection” with the MODE key. The
message
[np is displayed for 1 sec. and then the
current setting is displayed. Select either hysteresis or switch operation
dis-
play with the keys.
Display section Select “Display Selection” with the MODE key. The message s[l
displayed for 1 sec. and then the current setting is displayed. Select
pressure display by PSI npa or display scaling (Arbitrary units defied by
user) et[ with the keys.
Scaling Display of DP (Used for arbitrary unit, user defined, scaling) When the et[ is selected in”Display Selection”, the display value of DP for applied pressure displays as an arbitrary scaling display. This is a function to scale the min/max display value for DP display and has no effect on applied pressure and analog output.
Select “Display Scaling of DP with the MODE key. The message d-p is displayed for 1 sec. and then the current setting mode’s decimal point position is displayed. Change the decimal point position value with the keys.
The pressure range min/max value can be set in the same way using the
MODE and keys. The pressure range min/max display values are
stored internally as operation coefficients. When “Display Scaling” et[ is
selected, these coefficients are used for scaling and LED display.
Ex.) With a pressure range of 0 to 150 psid (0 to 100% F.S.), main unit dis-
play of 000.0 to 150.0 (factory set) is changed to a display of 0.000 to 1.000.
(User defined unit, in this case 1MPa)
d-p Dec. point position (from least significant digit): 0.1 .003
d-l Min. pressure range value:
0.0 .000
d-k Max. pressure range value:
150.0 1.000
Filter section The GC55 is equipped with 5 internal time constant filters. Use this function when pressure fluctuations can result in erratic, difficult to read displays. The time constant for the selected filters reflects on the switch outputs as well as the analog output. Select “Filter Selection” with the MODE key. The message f1l is displayed for 1 sec. and then the current setting mode’s decimal point position is displayed. Change the decimal point position value with the keys.
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Entering the setting value in function setting mode resets all of the setting
f-0 – – – – – No filter
f-1 – – – – – Time constant 25ms
f-2 – – – – – Time constant 250ms
f-3 – – – – – Time constant 2.5 sec
f-4 – – – – – Time constant 5 sec
f-5 – – – – – Time constant 10sec
Analog selection Select “Analog Selection” with the MODE key. The message is ana displayed for 1 sec. and then the pressure of analog output is displayed. Select DP, P1 or P2 with the keys.
Analog output scaling This mode is for setting the pressure for the analog output zero point and span point.
Display by analog selection is scaled as 0 to 100% (Zero point : 1Vdc or 4mA
dc, Span : 5Vdc or 20mA dc). Select “Analog Scaling” with the
MODE key. The message a-l is displayed for 1 sec. and the current pressure’s
analog output zero point (1Vdc) is displayed as a percentage. Change the
numeric value with the keys.
The analog output span point’s a-k pressure can be set in the same way using the MODE and keys.
Ex.) With Analog output of 1 to 5Vdc at pressure range of 0 to 100 psid (0 to 100%F.S.), output is changed to 1 to 5Vdc at 0 to 90 psid.
a-k Press. at time of analog output zero point: 0.0% F.S. 0.0% F.S. (1Vdc output with pressure range 0% F.S.)
a-l Press. at time of analog output span point: 100.0% F.S. 90% F.S. (5Vdc output with pressure range 90% F.S.)
10. switch setting Mode setup In Measurement Mode press the change to Switch Setting Mode.
MODE
key (release within 3 sec.) to
switch setting Mode There are two switches, OUT1 and OUT2. Both “Hysteresis (upper/ lower limit)” and “Window Comparator” operations can be selected in the function setting mode (switch operation selection). Those two operations can be selected at once, and can be set. Both OUT1 and OUT2 can be set
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independently to a max on/off delay of 2 seconds. In the following
explanation, if the switch’s output conditions are met their output state will
become On, and “Switch LED (OUT1, OUT2)” will light up.
PLEASE NOTE that if the switch’s setting value is set outside the display
range, the switch’s setting value can be rewritten automatically by the
function setting mode operation.
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11. switch operation Hysteresis/Deadband setting the upper limit. This is
the mode in which the switch operates with the setting value (A) as the upper
limit. The upper limit setting is determined when you select a positive number
(including 0) for setting value (b).
setting the lower limit. This is the mode in which the switch operates with
the setting value (A) as the lower limit. The lower limit setting is
determined when you select a negative number for setting value (b)
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operation of Window Comparator
12. Loop Check Mode setup steps In measurement mode press the change to Loop Check Mode.
MODE + key (release within 3 sec.) to
Regardless of applied pressure, display and analog output can be tested manually using the keys, useful for simulation testing of the analog output and switch output wiring. After the switch setting press lop for 1 sec. to change into Loop Check Mode. The initial value will be the value displayed immediately before entering Loop check mode.
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Less than 1 sec.
13. other Functions Basic Key operations In all setting modes, values are set
with the keys. Use the key to increase and the key to decrease the value. A
repeat state occurs in three phases of speed when the keys are pressed for
more than 0.5 seconds to increase or decrease numerical value. keys are also
used for setting switch, unit and filter in the function setting mode.
Adjusting the zero point of P1, P2 In measurement mode, select display to
adjust zero using SEL key. Press MODE + keys for more than 3 seconds (until
“—” display blinks) after releasing pressure from the pressure port. Auto-
matic zero adjustment takes place approximately 1 second later for pressure
display to be zero. When the zero adjustment is successful, adj is displayed.
Error e-0 displays for 1 second when applied presure was outside of range of
5 to 5% F.S., zero adjustment will not be allowed. Adjusting the zero point
of DP Only when display scaling et[ is selected in display select on function
setting mode, zero adjustment can be done. Press MODE + keys for more than 3
seconds (until “—” display blinks) after releasing pressure from the pressure
ports. Automatic zero adjustment takes place approximately 1 second later.
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When zero adjustment is successful, adj displays. When in 1999 to 1999 of
display range, adjustment can be done. On DP display scaling of function mode
et[ , zero adjustment value is reset and returns to initial value when each
setting changes.
e-0 displays for 1 second when DP zero adjustment cannot be done.
Maximum / Minimum Pressure Capture The GC55 unit keeps the maximum and minimum
pressure level applied to the pressure port as peak and bottom values
respectively, in the internal memory. The peak and bottom values are displayed
while holding the or keys respectively. Message pe+ is displayed for one
second and selected Max/Min value is displayed by this operation. Maximum and
minimum values are reset when you reset power to the unit or by the following
procedure: Resetting Maximum value: While holding the key, press the key.
Resetting Minimum value: While holding the key, press the key. Key Lock In
measurement mode, press the MODE + SEL keys after the message lo[ displays for
1 second, indicating that the unit has entered into the key lock state. All
operations except Maximum / Minimum hold display and display selections cannot
be accessed. The key lock mode cannot be reset by turning the power OFF and
ON. It can be reset only by following the unlocking procedure. Press the MODE
- SEL keys, message unl displays for 1 second and key lock is canceled.
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error Display An error message and a pressure are alternately displayed when one of the following errors occurs while in measurement mode.
error Display
Definition
Definition
FFF * -FFF
Pressure above 105% F.S. of
sensor range is applied, or
when indicated value exceeded
1999. (If pressure display is
not selected, LED blinks.)
Return pressure to
Pressure less than 5% F.S. within rated range.
of sensor range is applied, or
when indicated value exceed-
ed 1999. (If pressure display
is not selected, LED blinks.)
Pressure outside of the range Open the unit to the of ±5% F.S. is applied during atmosphere and zero adjustment of P1 and P2. adjust zero.
Adjusting zero point when psi Select et( “this is
e-0 is selected on DP display selection.
what will show on your screen” on DP display
selection and adjust
zero point, When in
“PSI” mode zero
adjustments can be
done on P1 and P2
respectively but not DP.
Note: *Maximum operating static (line) pressure is the full scale range of the unit ordered/specified.
Backup of setting Values The unit has an internal EEPROM to maintain settings and the key lock state for power interruption.
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14. MAInTenAnCe AnD WARRAnTY Periodic Inspection Depending upon the type of
use periodic inspection is recommeded at least once a year. Please refer to
the following items for periodic inspection. (1) Appearance (2) Display/output
check via appropriate pressure standard(1) (3) Display/output check via Loop
Check(2) CAUTIon · Avoid electrostatic charging. When cleaning this product,
please use a soft, damp, cloth. · Do not use thinner, etc. which may cause
deterioration and failure. Product warranty Except as otherwise provided, the
product warranty of this product is as follows: Period: 12 months after
delivery Warrantable defects: Defects resulting from the design and
manufacture of our company, the quality of the material, etc. Implementation
of warranty: This warranty will be completed by substitution or repair of the
product concerned. We will not take responsibility for consequential damages
caused by product defects. · If you have any questions about this document,
please contact the sales office or distributor nearest you. · This document is
subject to change without notice due to upgrade etc.
(1) If zero correction is required refer to section 13. (2) Loop check, see
section 12.
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© 2012 Ashcroft Inc. 250 East Main Street, Stratford, CT 06614 USA Tel:
203-378-8281, Fax:
203-385-0402 www.ashcroft.com All sales
subject to standard terms and conditions of sale. I&M011-10158. Rev. D 6/12
24