Gefran HMX SERIES Data Sheet

SMART HART MERCURY FILLED MELT PRESSURE TRANSMITTERS

FOR APPLICATIONS IN POTENTIALLY EXPLOSIVE ATMOSPHERES

HMX SERIES - CURRENT OUTPUT AND PERFORMANCE LEVEL ‘c’

4...20mA Output

The HMX series of Gefran are pressure transmitters with
HART communication protocol for using in high temperatu­re environment with explosive atmosphere presence.
The main characteristic of this series is the capability to
read temperature of the media up to 400°C.
The constructive principle is based on the hydraulic tra­smission of the pressure.
The fluid-filled system assures the temperature stability.
The physical measure is transformed in a electrical mea­sure by means of strain-gauge technology.

MAIN FEATURES

• Pressure ranges from: 0-17 a 0-2000 bar/0-250 a 0-30000 psi

• Extensimetric measurement principle with Wheatstone bridge

• Accuracy: < ±0.25% FSO (H); < ±0.5% FSO (M)

• Calibration signal 80% FSO internally generated

• Completely interchangeable with all existing products

• Protection level: IP65 (6-pin connector)

• 1/2-20UNF, M18x1.5 standard threads; other types available

on request

• Standard diaphragm is 15-5 PH stainless steel with GTP+
coating

• 17-7 PH corrugated stainless steel diaphragm with GTP+ coating
for ranges below 100 bar-1500 psi

• Other diaphragm types available on request

HMX0 The rigid rod configuration provides fast and easy
installation.
HMX1 The flexible rod configuration is suitable for applications
demanding greater thermal isolation and where installa­ tion would otherwise be difficult.
HMX2 This configuration lets you measure process pressure
and temperature at the same point with a single installa­ tion.
HMX3 The configuration with exposed tip is ideal for applica­ tions in limited space.

Main intrinsic safety characteristics

Transmitter designed and produced in compliance with Directive
ATEX 2014/34/EU and according to European standards.
Protection mode: group II, category 1G, 1D
GAS protection mode: Ex ia IIC T6, T5, T4 Ga (Ambient Temp.:

-20°C...+60°C / +75°C / +85°C)
DUST protection mode: Ex ia IIIC T85°C, T100°C, T135°C Da
IP65 (Ambient Temp.: -20°C...+60°C / +75°C / +85°C)

Maximum voltage 30 V

Maximum current 100 mA

Maximum power 0,75 W

Maximum inductance (*)

Maximum capacity (*) 10 nF

17 mH

TECHNICAL SPECIFICATIONS

Accuracy (1)

Resolution 16 bit

Measurement range

Rangeability 3:1

Maximum overpressure (without
degrading performances)

Measurement principle Extensimetric

Power supply 13...30Vdc

Maximum current absorption 23mA

Output signal Full Scale (FSO) 20mA

Zero balance (tollerance ± 0.25%
FSO)

Calibration signal 80% FSO

Power supply polarity reverse
protection

Compensated temperature range
housing

Operating temperature range
housing

Storage temperature range housing -40...+125°C

Thermal drift in compensated range:
Zero / Calibration / Sensibility

Diaphragm maximum temperature 400°C / 750°F

Zero drift due to change in process
temperature (zero)

Standard material in contact with
process medium

Thermocouple (model HMX2) STD: type “J” (isolated junction)

Protection degree
(with 6-pole female connector)

FSO = Full scale output
(1) BFSL method (Best Fit Straight Line): includes combined effects of Non-Linearity,
Hysteresis and Repeatability

(*) includes inductance levels and capacity of a cable:
(typical L 1microH/m and typical C 100pF/m) with maximum length 15m.

The Melt pressure transmitters must be connected to other equipment
(galvanic isolation barriers) with individual ATEX certification such as
[Ex ia Ga] IIC. The thermocouple circuit must be powered by means of

H <±0.25%FSO (100...2000 bar)
M <±0.5%FSO (17...2000 bar)

0..17 to 0..2000bar

0..250 to 0..30000psi

2 x FS

1.5 x FS above 1000bar/15000psi

4mA

YES

0...+85°C

-30...+85°C

< 0.02% FSO/°C

< 0.02 bar/°C

Diaphragm:

• 15-5 PH with GTP+ coating

• 17-7 PH corrugated diaphragm with
GTP+ coating for ranges <100bar
(1500psi)
Stem: • 17-4 PH

IP65

MECHANICAL DIMENSIONS

HMX1HMX0

D1

D2

D3

D4

D5

A

B

C

Ch

[Hex]

1/2 - 20UNF

ø7.8 -0.05

[ ø0.31” -0.002 ]

ø10.5 -0.025

[ ø0.41” -0.001 ]

ø10.67

[ ø0.42” ]

ø12.7

[ ø0.5” ]

5.56 -0.26

[ 0.22” -0.01 ]

11.2

[ 0.44” ]

15.74

[ 0.62” ]

16

[ 5/8” ]

D1

D2

D3

D4

D5

A

B

C

Ch

[Hex]

M18x1.5

ø10 -0.05

[ ø0.394” -0.002 ]

ø16 -0.08

[ ø0.63” -0.003 ]

ø16 -0.4

[ ø0.63” -0.016 ]

ø18

[ ø0.71” ]

6 -0.26

[ 0.24” -0.01 ]

14.8 -0.4

[ 0.58” -0.016 ]

19

[ 0.75” ]

19

[ 3/4” ]

NOTE: dimensions refer to rigid stem length option “4” (153 mm– 6”)

WARNING: For installation use a maximum tightening torque of 56 Nm (500 in-lb)