Agilent Technologies E5052 User manual
Agilent Technologies
Agilent
E5052 Liquid Helium
Monitor
User Guide
Notices
© Agilent Technologies, Inc. 2012
No part of this manual may be reproduced
in any form or by any means (including
electronic storage and retrieval or transla-
tion into a foreign language) without prior
agreement and written consent from
Agilent Technologies, Inc. as governed by
United States and international copyright
laws.
Manual Part Number
9100382700
Edition
Revision A, April 2012
Printed in USA
Agilent Technologies, Inc.
5301 Stevens Creek Boulevard
Santa Clara, CA 95051 USA
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Safety Notices
CAUTION
A CAUTION notice denotes a haz-
ard. It calls attention to an operat-
ing procedure, practice, or the like
that, if not correctly performed or
adhered to, could result in damage
to the product or loss of important
data. Do not proceed beyond a
CAUTION notice until the indicated
conditions are fully understood and
met.
WARNING
A WARNING notice denotes a
hazard. It calls attention to an
operating procedure, practice, or
the like that, if not correctly per-
formed or adhered to, could result
in personal injury or death. Do not
proceed beyond a WARNING
notice until the indicated condi-
tions are fully understood and met.
E5052 Liquid Helium Monitor User Guide 1
Contents
1 Introduction
Safety 4
Guide de sécurité 5
FCC Notice 6
Compliance Notice 7
Important Notice 8
Disclaimer 8
Contact Information 9
Europe 9
USA 9
Agilent website (all countries) 9
2 Operation
Features and Description 12
Operating Principle 13
Specifications 14
Calibration 16
Operation 18
Setting the low level alarm 18
Using the analog output 19
Troubleshooting 20
2 E5052 Liquid Helium Monitor User Guide
4 E5052 Liquid Helium Monitor User Guide
1Introduction
Safety
Refer to accompanying documents.
To select the mains supply voltage or replace mains fuses,
prise open the flap on the mains input socket using a
suitable tool in the slot provided. This affords access to the
voltage select drum and two fuse trays.
To select the supply voltage pull out the drum and rotate
until the 230V~ or 115V~ lettering is uppermost, ie. in line
with the drum slots, and replace. When the socket flap is
replaced the correct voltage must be visible through the
window.
To replace the input fuse, pull out the fuse trays and replace
with the correct value of fuse. Re- insert the fuse trays,
noting the correct orientation of the arrows.
WARNING
Danger of electrical shock. Isolate or disconnect from mains supply
before opening this unit for any reason.
WARNING
For continued protection against risk of fire or electric shock,
replace fuses with the same type, rating and UL listing.
CAUTION
This unit contains internal protection fuses. Follow the guidelines in
Troubleshooting section before replacement of these devices.
CAUTION
This unit has been pre-set to a voltage range suitable for the
national supply. The unit has a selectable input voltage, 110V~ or
220V~. Fuses F1 and F2 must be rated to suit the input voltage:
•For110V~ use, they must be rated at T250mA 250V.
•For 220V~ use, they must be rated at T100mA 250V.
Introduction 1
E5052 Liquid Helium Monitor User Guide 5
Guide de sécurité
Attention, voir aussi les documents joints
1. AVERTISSEMENT : Isolez ou débranchez le système de
toute alimentation électrique avant d’ouvrir cette unité,
quelle que soit la raison. ÉLÉMENTS SOUS TENSION À
L’INTÉRIEUR.
2. AVERTISSEMENT : Cet équipement doit être relié à une
mise à la terre. Pour une protection continue contre les
risques d’incendie ou de choc électrique, remplacez les
fusibles par d’autres de même type, calibre et normes UL.
3. ATTENTION : Cette unité contient des coupe- circuits à
fusibles internes. Suivez les indications inscrites dans la
section Dépannage du manuel avant de remplacer ces
éléments. Seul le personnel dûment formé doit être autorisé
à retirer les panneaux de l’équipement.
4. ATTENTION : Cette unité a été préréglée pour une plage
de tension compatible avec les normes électriques de votre
pays. Cette unité a une tension d’entrée ajustable : 100Vca,
120Vca, 220Vca, 240Vca ou 115Vca, 230Vca. Les fusibles F1
et F2 doivent être du bon calibre pour supporter la tension
d’entrée. Si celle- ci est de 100Vca, 115Vca ou 120Vca, utilisez
des fusibles de calibre T250mA 250V. Si la tension est de
220Vca, 230Vca ou 240Vca, utilisez des fusibles de calibre
T100mA 250V.
Pour sélectionner la tension d’alimentation principale ou
remplacer les fusibles, ouvrez le panneau d’accès au module
d’alimentation générale à l’aide d’un outil adéquat dans les
fentes prévues à cet effet. Cela permet d’accéder au bouton
de sélection de tension et à deux porte- fusibles.
Pour sélectionner la tension d’entrée, tirez vers vous le
bouton de sélection et faites- le tourner jusqu’à l’alignement
de l’inscription souhaitée avec la fente du bouton, puis
repoussez- le. Quand le panneau du module est remis en
place, vous devez voir la bonne tension à travers la fenêtre.
Pour remplacer le fusible d’alimentation, sortez les
porte- fusibles et procédez au remplacement avec un fusible
adéquat. Remettez les porte- fusibles en place en s’assurant
de la bonne orientation des flèches.
5. Cet équipement ne peut pas et ne doit pas être utilisé en
présence de produits inflammables.
6 E5052 Liquid Helium Monitor User Guide
1Introduction
FCC Notice
Federal communications commission statement on Class A.
This unit has been tested and found to comply with the
limits for a Class A digital device, pursuant to part is of the
FCC rules. These limits are designed to provide reasonable
protection against harmful interference when the unit is
operated in a commercial, industrial or business
environment.
Operating is subject to the following two conditions:
1The unit may not cause harmful interference.
2This device must accept any interference received,
including interference that may cause undesired
operation.
Note that FCC regulations provide that changes or
modifications not expressly approved by Magnex Scientific
Ltd could void your authority to operate this equipment.
Introduction 1
E5052 Liquid Helium Monitor User Guide 7
Compliance Notice
Marking by the symbol indicates compliance of this
device to the EMC (electromagnetic compatibility) and LV
(low voltage) directives of the European Community. This
unit is to be installed and operated as detailed. Any
modification or maintenance procedure undertaken which is
not approved by Agilent Technologies UK Ltd could nullify
the marking of this product and lead to prosecution. A
'Declaration Of Conformity' in accordance with the above
directive has been made and is located at Agilent
Technologies, Yarnton, Oxfordshire, UK.
8 E5052 Liquid Helium Monitor User Guide
1Introduction
Important Notice
Inspect goods immediately on arrival for possible transit
damage, and notify Agilent Technologies within three days of
receipt of goods. Failure to do this invalidates any possible
claim.
Disclaimer
Every precaution has been taken in the preparation of this
publication. Agilent Technologies assumes no responsibility
for errors or omissions. Neither is any liability assumed for
damages resulting from the use of the information contained
herein.
Introduction 1
E5052 Liquid Helium Monitor User Guide 9
Contact Information
Europe
Address:
Agilent Technologies UK Ltd.
6 Mead Road
Oxford Industrial Estate
Yarnton, Oxfordshire OX5 1QU
Telephone Numbers:
To find contact information for your country, click the
following link, select your country, and then click Go.
http://www.chem.agilent.com/en- us/ContactUS/Pages/Contact
Us.aspx
USA
Address:
Agilent Technologies, Inc.
5301 Stevens Creek Blvd.
Santa Clara, CA 95051
Telephone Numbers:
Toll Free: +1 (800) 227 9770
Agilent website (all countries)
To find contact information for your country, click the
following link, select your country, and then click Go.
http://www.chem.agilent.com/en- us/ContactUS/Pages/Contact
Us.aspx
10 E5052 Liquid Helium Monitor User Guide
1Introduction
12 E5052 Liquid Helium Monitor User Guide
2Operation
Features and Description
The E5052 Liquid Helium Level Monitor has the following
features:
•Direct digital display of liquid helium level in mm.
•Analog voltage output.
•Variable interval sample and hold facility fill/normal.
•Adjustable low level alarm facility with visual and
change- over relay output.
•Modular design.
The model E5052 Monitor has been designed to operate with
a superconducting level probe and provides a sampled digital
display of liquid helium levels in cryogenic vessels.
An analog voltage output connector is provided to allow the
helium level to be logged. This also includes a 'read on
demand' input.
By the use of an adjustable interval sample and hold facility
liquid helium consumption during operation is minimized.
The instrument also incorporates an adjustable low level
alarm facility with both visual and electrical outputs and can
be offered for use with a range of superconducting level
probes.
Operation 2
E5052 Liquid Helium Monitor User Guide 13
Operating Principle
The helium level probe consists of a length of
superconducting wire with a heater wound around the top.
A constant current is passed through the heater and probe
wires. The heater maintains that part of the probe that is
above the liquid level at a temperature above its critical
temperature for super- conductivity. The part of the probe
above the liquid therefore has resistance, the part immersed
has none. A voltage signal is available from the probe
which is proportional to the length of the probe not
immersed in the liquid. This voltage is subtracted from a
reference voltage and applied to a linear measuring circuit
which drives a digital panel meter.
Heating the probe causes the liquid to boil, therefore to
minimise this effect the helium level is read at intervals and
'held' on the display. The sample interval is derived and
controlled by a timer and logic circuits, which allows current
to flow into the probe heater until the temperature of the
probe above the liquid helium level reaches a steady
condition. A low level alarm system is driven from the
measuring circuits.
14 E5052 Liquid Helium Monitor User Guide
2Operation
Specifications
Output display 3 ½ digit L.C.D. scale in mm
Instant updating facility Via front panel push button
Sample and hold interval:
normal
fill
7 hours (+/- 20%)
10 seconds (+/- 20%)
Interval selection Via front panel switch
Maximum number of probes 2
Probe selection Via front panel switch
Low level alarm indicator Via flashing LED display
Low level alarm output Relay change-over contacts
Maximum switched voltage 30Vdc Maximum switched
current 1 Adc
(mains failure and probe open circuit will indicate an
alarm condition)
Low level alarm adjustment Via front panel multiturn preset.
Span 0-95% of total length
(factory set to 50%)
Analog Voltage Output 3mV = 1mm (valid voltage only present when the 'read on
demand' signal is active)
Mains input voltage 110/220V ~ selectable
Mains input current 80mA @ 220V ~
170mA @ 110V ~
Mains input frequency 50/60 Hz
Fuse rating F1, F2: T100mA 250V for 220V supply
OR T250mA 250V for 110V supply
F3: T800mA 250V
F5: T200mA 250V
Dimensions:
Height
Width
Depth
128mm (3U)
106mm (21E)
220mm (Plug in unit or stand alone)
Probe Input Connector
See connector details on the following
page.
9 way 'D' socket
Operation 2
E5052 Liquid Helium Monitor User Guide 15
Connector Details
Liquid Helium Probe
Connector Probe
1Probe1 V+
2Probe1 I+
3Probe1 V+
4Probe1 I-
5N/C
6Probe2 V+
7Probe2 I+
8Probe2 V+
9Probe2 I-
Probe resistance 0.2-0.05/mm
•The probe wire resistance varies from batch to batch. If the exact probe
resistance is required please contact Agilent with the probe serial number.
Excitation current 80-110mA
dependent upon probe wire resistance
Probe length 100mm to 2000mm
Probe output connector 10 way SIL plug
16 E5052 Liquid Helium Monitor User Guide
2Operation
Calibration
This monitor has been calibrated for a particular probe
length. Should the instrument fail to produce accurate
readings or is to be used with a different probe, recalibrate
it as follows. Use a test unit to simulate the probe that has
a circuit shown in Figure 1 on page 17.
Before you begin You will need the following equipment for this procedure:
•Multimeter
•Helium monitor calibration unit
•Insulated adjustment tool
1Connect the calibration unit to the helium monitor via
the 9 'D' PROBE plug at the rear of the helium monitor.
2Calculate the resistance for the active length of the
helium probe for which calibration is required and set
the variable potentiometer on the calibration unit to this
resistance.
3Set the monitor READ time to NORMAL.
4The probe current (as listed in 'Specifications' section or
advised by Magnex) is set by adjusting the rear panel
potentiometer PROBE CURRENT or on earlier models
potentiometer VR1 on the power supply PCB. The probe
current is measured as a voltage across the 10 HEATER
resistor on the calibration unit (hold the READ button in
when adjusting probe current).
5To select the required probe operate the front panel
switch marked PROBE 1- 2.
6The helium monitor digital panel meter (DPM) is set to
read zero with the calculated resistance set on the
calibration unit. Place the calibration unit PROBE switch
to the RESISTANCE position. Adjust the appropriate rear
panel mounted PROBE ZERO potentiometer until the
DPM reads zero (hold the READ button in when
adjusting for zero).
7Place the calibration unit PROBE switch to the S/C
position and adjust the rear panel mounted DPM SPAN
potentiometer until the DPM reads the active length of
the helium probe (hold the READ button in when
adjusting for the active length).
CAUTION
Incorrect adjustment of the probe current can upset the operation of
the instrument and cause spurious readings.
Operation 2
E5052 Liquid Helium Monitor User Guide 17
Figure 1 Helium Monitor Calibration Test Unit Circuit
18 E5052 Liquid Helium Monitor User Guide
2Operation
Operation
Setting the low level alarm
The helium monitor alarm level can be set by pressing the
DISPLAY button and changing the ADJUST potentiometer
until the DPM reads the desired level (hold the DISPLAY
button in when adjusting for the alarm level). Once the
alarm level has been set, press the READ button to display
the current probe level.
An alarm state is indicated by the flashing ALARM LED on
the front panel and the operation of the rear panel alarm
relay contacts, which allow the inclusion of additional
external alarm indicators. During normal operation contacts
1 & 2 will be connected and 2 & 3 open circuit.
During alarm conditions contacts 2 & 3 will be connected
and 1 & 2 open circuit.
A mains power failure and open circuit probe will cause an
alarm condition.
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