Ashcroft GL42 User Manual

GL42 DIFFERENTIAL PRESSURE
TRANSMITTER INSTALLATION &
MAINTENANCE SHEET

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., 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.

3. STATIC ELECTRICAL CHARGES:

Any electrical device may be susceptible to damage when
exposed to static electrical charges. To avoid damage to the
transducer the operator/installer should follow proper ESD
(electrostatic discharge) protection procedures before han­dling the pressure transducer.

4. DESCRIPTION

The Ashcroft® Model GL42 is a low differential pressure
transmitter to be used on clean, dry, non-corrosive gases. It
is available in two accuracy classes and its performance is
traceable to the U. S. National Institute of Standards and
Technology (NIST). The 7 or 5 located in the fifth position

of the product code distinguishes a 1.0% from a 0.5% accu­racy transmitter. Both unidirectional (e.g. 0 to +1.0 IW) or bi­directional (e.g. ±2.0 IW) models are available.

5. SPECIFICATIONS

Reference condition: 77°F (25°C)

Accuracy*: ±0.50% or ±1.00% F.S. (URL)

(* includes linearity, hysteresis and repeatability)

Repeatability: ≤ ±0.1 % F.S.

Stability: </= 0.5% F.S. / Year

Zero / Span Adjustment: ±5% F.S.

Standard-Ranges (Unidirectional):

0.10˝ to 25.00˝ in H

Standard-Ranges (Bidirectional):

±0.05˝ to ±15.0˝ in H

6. ENVIRONMENTAL SPECIFICATIONS

Enclosure Rating: IP65

Temperature Limits:

Operating: –4/158°F (–20/70°C)
Storage: -40/194°F (–40/90°C)
Compensated: 35/129°F (2/54°C)

(10-90% R.H. non-condensing)

Temperature Coefficients:

Zero & Span ±0.06%/K within 35/129°F (2/54°C)
Ref. 77°F (25°C)

0

2

0

2

FUNCTIONAL SPECIFICATIONS

Static (line) Pressure: All Pressure Ranges

Proof: 14.5 psi (1 bar)
Burst: 24.65 psi (1.7 bar)
Max. Static: 24.65 psi (1.7 bar)

8. ELECTRICAL SPECIFICATIONS

LCD Display: 4 Digit

LCD Screen Dimensions:

Width: 1.77” (45mm) / Height: 0.75” (19mm)

LCD Character Size:

Height: 0.21” (5.4mm) / Width: 0.45” (11.5mm)

Output Signal: 4-20 mA ( 2 wire)

Supply Voltage: 19-36 Vdc (Nominal 24 Vdc)

Rangeability / Adjustment: Zero: ±1/3 F.S.

CE-Compliance: EN 61000-4-2, EN 61000-4-3

9. MECHANICAL SPECIFICATIONS

Process Connection: Brass / Aluminum

1/8” Female NPT or 1/4” Male Barbed Fitting

Electrical Connection:

½” Female DIN Cable Conduit (Standard)
PG9 Cable Gland (Option

Enclosure: Nylon

Cable Connection Socket: Nylon

Front Foil: Polyester

Electrical Connection: Screw Terminal

Weight: 9.9 oz (308 g)

Mounting:

Wall Mount (Standard)
DIN Rail (Option): EN 50022 / EN 50035 / EN 50045
Panel Mount (Option)

10. INTENDED USE

The GL42 is a 2-wire transmitter.

It is suitable for accurate measurement of low gauge, vacu­um or differential pressure of non-conductive and non-corro­sive gaseous media.

11. PRODUCT DESCRIPTION AND FUNCTION

a. Function diagram

© 2014 Ashcroft Inc. 250 East Main Street, Stratford, CT 06614 USA. Tel: [phone], Fax: [phone] www.ashcroft.com
All sales subject to standard terms and conditions of sale. I&M011-10227 5/14

. Design and mode of operation

b

he transmitter is based on a capacitance sensor element

T
with a micro machined differential capacitor using a patented
silicon-on-glass technology. This ultra-thin single crystal dia-

hragm provides excellent sensor repeatability and stability.

p

. 2-wire circuit

i

Sensor cross section

The silicon diaphragm sensor has no glues or other organics
to contribute a drift or mechanical degradation over time.

12. INSTALLATION AND ASSEMBLY

All supply lines should be arranged so that there are no me-

hanical forces acting on the device.

c

The GL42 is calibrated for vertical installation; however any
installation position is possible. If an installation position
other than vertical is selected, the zero-point signal can be
corrected as shown in Section 13b.

a. Process connection

• By authorized and qualified personnel only.

• All lines need to be depressurized when the instrument
is being connected.

• Appropriate steps must be taken to protect the device
from pressure surges.

• Check the suitability of the device for the media to be
measured.

• Maximum pressures shall be observed.

• Check that all connections are tight before use.

The pressure sensing lines need to be kept as short as pos­sible and installed without sharp bends to avoid interfering
delay times.

The pressure connections are marked with (+) and (-) sym­bols on the device. For differential pressure measurements,
the higher pressure is connected to the (+) side and the lower
pressure to the (-) side of the device.

If during installation the pressure measuring lines are already
under pressure, the zero-point cannot be checked and no
settings can be adjusted. In these cases, the device should
only be connected electrically first.

b. Electrical connection

• By authorized and qualified personnel only.

• The electrical connection of the device shall be per­formed according to local electrical codes

• Turn off power before connecting the device.

Power

GL42

Supply

in

P

ignal Name

S

1 + Power Supply / Output Signal +Ub / +Sig

2 - Power Supply / Output Signal -Ub / -Sig

ii. Pin assignment

13. COMMISSIONING

All electrical supply, operating and measuring lines, and the
pressure connections must have been correctly installed be-

ore commissioning. All supply lines are arranged so that

f
there are no mechanical forces acting on the device.

Check that the pressure connections do not leak before
commissioning.

a. Configuration of the LCD display

To configure the LCD display, remove the lid by unscrewing

the four screws on the front of the device. This gives you ac­cess to the DIP switch used for configuration.

S1 S2 S3 S4 S5 S6 S7 S8

Unit Decimal Attenuation reserved

Point

The following overview shows the basic function of the indi­vidual switches:

Using the following switch settings, the display can now be
configured at your discretion. Changes to the configuration
via the DIP switch are shown immediately on the display.

A “1” equals the switch setting “ON”; a “0” means that the
switch setting is “OFF”.

Unit S1 S2 S3 S4 S5 S6 S7 S8

inWC 00 XX

mbar 10 XX

kPa 01 XX

Pa 11 XX

Decimal

Point S1 S2 S3 S4 S5 S6 S7 S8

000XX

1.0 10 XX

2.00 01 XX

3.000 11 XX

Meter

Display

Damping S1 S2 S3 S4 S5 S6 S7 S8

none 00XX

1 s 10XX

3 s 01XX

5 s 11XX

. Switch settings

44

33

22

11

PRESSURE PORTS
(1/4 BARBED FITTING)

ELECTRICAL CONNECTION
(1/2 NPT FEMALE THREAD)

("CD" option shown)

1.05

3.51

2.94

2.99

Ø

0.19

4 Places

1/8 NPT MALE

4.89

2.95

2.47

i

i. Functional description of display damping

i

he damping only refers to the display value of the LCD dis-

T
play and not the power output signal of the GL42 2-wire dif­ferential pressure transmitter.

The display value is damped according to an e-function. The

et damping time corresponds to a change of the displayed

s
pressure value of 90% of the change of the input pressure.

Item Description

1

KL1 - PCB Terminal Block for power supply and signal output

2 S1 – DIP Switch for LCD Configuration

3 SPAN Adjustment Potentiometer

4 ZERO Adjustment Potentiometer

The final display value is achieved after a four-fold damping
time.

b. Adjustment

To adjust the differential pressure transmitter, remove the lid
by unscrewing the four screws on the front of the device.

The zero-point and the range can be adjusted via the poten­tiometer "ZERO" (zero-point) and "SPAN" (range). Ensure
correct alignment of the sensor in terms of the subsequent
installation to avoid position-dependent measuring deviations
when used later.

4. MAINTENANCE

1

he device does not require maintenance. In order to ensure

T
reliable operation and a long service life of the device we
recommend regular checking of the device as follows:

• Check the function in connection with system
omponents.

c

Check the tightness of the pressure connection lines.

•

Check the electrical connections.

•

he exact test cycles have to be adapted to the operating

T
and environmental conditions. The operating manuals of all
other devices are also to be observed if there is an interac-

ion of different device components.

t

5. TRANSPORT

1

he product must be protected against severe impacts.

T
Therefore transport is to be effected only in the packaging in­tended for transport.

16. SERVICE

All defective or faulty devices are to be sent directly to Ash­croft Inc. We would ask you to coordinate all device returns
with our inside sales department. Our inside sales depart­ment will issue an RMA number and give instructions on how
to ship the return.

WARNING

Remaining medium in and on dismantled measuring instru­ments may cause danger to persons, environment and equip­ment. Take reasonable precautions! Clean the instru-ment
thoroughly if necessary.

To return the unit please choose the original packaging or a
packaging intended for transport.

17. DISPOSAL

Incorrect disposal can put the environment at risk.

Kindly help us protecting the environment and dispose of or
recycle the used products in accordance with the relevant
regulations.

18. DIMENSIONED DRAWINGS

(All units in mm unless otherwise specified.

© 2014 Ashcroft Inc. 250 East Main Street, Stratford, CT 06614 USA Tel: [phone], Fax: [phone] www.ashcroft.com
All sales subject to standard terms and conditions of sale. I&M011-10227 6/14