Ashcroft H2 User Manual

65

2.56

22

.87

H2 PRESSURE TRANSMITTER
INSTRUCTION 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., 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 electri-
cal 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

Ashcroft®H2 Pressure Transmitter,
Typical Dimensions and Construction*

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 damag-

ing to pressure transducers if the pipe
is originally empty. To avoid damaging
surges, fluid lines should remain full (if

ossible), pumps should be brought up

p
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:

• Operator/installer should follow the
proper ESD (electrostatic discharge)
protection procedures before han­dling the pressure transducer.

• 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.

ounting

M

The H2 transmitter requires no special

mounting hardware, and can be mounted

n any plane with negligible position error.

i

Although the unit can withstand normal
vibration without damage or significant
output effects, it is always good practice
to mount the transducer where there is
minimum vibration.

or units with NPT type pressure fittings

F
apply Teflon

®

tape (approximately 11⁄2 rev-
olutions) or an equivalent sealant to the
threads before installing.

When tightening, apply a wrench to the
hex wrench flats located just above the
pressure fitting. DO NOT tighten by using
a pipe wrench on the housing. Approximate
torque is 18.45 pounds force foot (25 Nm).

Power Supply

Power Supply Voltage

Output Signal Min Max

4-20mA 10Vdc* 32Vdc
0-5Vdc 13Vdc 32Vdc
0-10V 13Vdc 32Vdc

* For transmitters with 4-20mA output

signal, the minimum voltage at the termi­nals is 10Vdc. However, the minimum
supply voltage should be calculated
using the following graph and formula.

Loop Supply Voltage vs. Loop Resistance

1000

800

600

400

200

Loop Resistance (Ohms)

0

10

Loop Supply Voltage (Vdc)

Vmin = 10V+ (.022A x RL) (includes a 10% safety factor)
R

= RS+ R

L

RL= Loop Resistance (ohms)
R
R

W

= Sense Resistance (ohms)

S

= Wire Resistance (ohms)

W

Operating

Region

20 30

Dimensions and construction details may vary

*

based on product specified.

© 2013 Ashcroft Inc. All rights reserved. 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&M011-10201-H2. Rev. 03/13

H2 PRESSURE TRANSMITTER

+

+

–

P

OWER

S

UPPLY

(

+)

(

–)

TRANSDUCER

–

V+

V

–

P

IN 1

PIN 2

4-20mA

METER

OR OTHER DEVICE

+

+

–

–

POWER
SUPPLY

METER

OR OTHER DEVICE

TRANSDUCER

(Common)

(+ Power)

(+ Output)

PIN 1

PIN 2

PIN 3

3-Wire Voltage

12

.453

15

.591

PIN A

PIN B

PIN C

PIN D

PIN E

PIN F

(B6) 6 PIN BENDIX (MIL-C-26482)

11

.433

11

.413

PIN 3

PIN 2PIN 1

PIN 4

(EW) M12 TYPE (4 PIN)

30

1.181

21

.835

914

3'

(F2) 3' SHIELDED CABLE

.18

.64

1.320

2

1

3

Gnd.

INSTRUCTION SHEET

oise

N

For minimum noise susceptibility, avoid
running the transducer’s cable in a con-

uit that contains high current AC power

d
cables. Where possible avoid running
the cable near inductive equipment.

Shielded Cable

Units with shielded cable electrical termi­nation, connect the drain wire to the
guard terminal on the read out device or
measuring instrument, if available. In all
other cases connect to the ground or to
the power supply negative terminal.

Vent Tube (Cable Termination Only)

The cable has a clear Teflon
required at pressure ranges below 500
psi to provide atmospheric reference.
The open end should be placed in a
dry area.

H2 Wiring Diagrams

®

vent tube

Voltage Current

in #

P

Output Output
(3-wire) (2-wire)

A (+) Power (+) Power
B (-) Power (-) Supply
C Not Connected Not Connected
D (+) Output N
E Ground Not Connected
F Not Connected Not Connected

ot Connected

in

oltage Current

P

V

o. Output Output

N

(3-wire) (2-wire)

1 (+) Power (+) Power

2 Not Connected Not Connected

3 (-) Power Out
4 Out Not Connected

H2 transducer has internal transient
protection: for safety, limit line-to­ground voltage to 36 Vdc max.

LOOK FOR THIS

AGENCY MARK ON

OUR PRODUCTS

© 2013 Ashcroft Inc. All rights reserved. 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&M011-10201-H2. Rev. 03/13

Wire Voltage Current

Color Output Output

(3-wire) (2-wire)

Red (+) Power (+) Power

Black (-) Power Out

White Out None

Voltage Current

Pin
No. Output Output

(3-wire) (2-wire)

1 (+) Power (+) Power
2 (-) Power (-) Power
3 (+) Output None
4 Ground Ground

(DN) HIRSCHMANN (43650-A)