6.0 Servo Gauges

854 ATG Servo Level Gauge

Kelvin Khoo

Honeywell Proprietary

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2Document control number

854 Series Servo gauge854 Series Servo gauge

TERMINAL COMP.

ELECTRONICCOMPARTMENTDRUM

HOUSING


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Archimedes Principle

• (Ark-i'-meed-eez).

• The basic idea is that the Displacer in a liquid produces an upward force equal to the weight of the displaced product. (Archimedes Principle).

• Weight = Displacer Weight• Buoyancy = Immersed Volume *Liquid Density• Apparent Weight = Weight – Buoyancy


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How is Archimedes• Archimedes (c.287 - c.212 BC)• c.250 Archimedes, Greek scholarly. • Archimedes was born in Syracuse on the eastern coast of Sicily and

educated in Alexandria in Egypt. He then returned to Syracuse, where he spent most of the rest of his life, devoting his time to research and experimentation in many fields.

• In mechanics he defined the principle of the lever and is credited with inventing the compound pulley and the hydraulic screw for raising water from a lower to higher level.

• He is most famous for discovering the law of hydrostatics, sometimes known as 'Archimedes' principle', stating that a body immersed in fluid loses weight equal to the weight of the amount of fluid itdisplaces. Archimedes is supposed to have made this discovery when stepping into his bath.


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854 Series Servo gaugesPrinciple of measurement

854 Series Servo gaugesPrinciple of measurement


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854 Series Servo gauges Modular design

854 Series Servo gauges Modular design

Terminal compartment

DrumHousing

Electronics

XPUSPUOptionPower

F

W

B


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Equilibrium Condition

• Equilibrium Condition– The weight of the partly immersed displacer balances with the weight

programmed to be measured by the Force Transducer (FT).• Liquid Level Moving Downward

– FT experience increasing weight– Upward force no longer acting on Displacer– FT communicate with Servo Controller– Servo Controller lower Displacer– Servo Controller stop until Apparent weight equals the programmed

weight• Liquid Level Moving Upward

– Reversed the “Moving Downward” process


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Equilibrium Condition

Buoyancy Largest = AscendForce Balance = HoverWeight Largest = Sink


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854 Series Servo gauges Drum Compartment

854 Series Servo gauges Drum Compartment

carbon-PTFEbearings

drum, engraved:- drum circumference- production number- serial number

O-ringsealing


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854 Series Servo gaugesMeasuring specifications

854 Series Servo gaugesMeasuring specifications

• Level accuracy < 0.4 mm• Level repeatability < 0.1 mm• Interface accuracy < 2 mm• Density accuracy < 3 kg/m3 *

• Temperature accuracy < 0.1 °C *

* Optional


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854 Series Servo gauges Available Models (1)


• Sealing facilities for Weights & Measures• Digital Pressure transmitters interface

for Honeywell / HART protocol• Temperature interface (average & spot)• Pressure versions

Medium pressure, High pressure• Drum compartment material

- stainless steel or aluminium• Safety approvals

FM, CSA, SAA, ATEX


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• Measuring range27 m., 37m., 35m. with 150 m. total wire lenght

• Wire materialSS-316, Hasteloy C22, Tantalum, Invar

• Mains supply110/130/220/240 V, optional 65 V

• Density measurement• Alarm contacts (2 * SPDT)


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854 Series Servo gauges Features and benefits

854 Series Servo gauges Features and benefits

Features• wire weight compensation

• hydrostatic tank deformation compensation

• adjustable balance setpoint

• servo density

• modular design with optional boards• full galvanic isolation• programmable via PET and PC

Benefits• smaller level error,smaller displacer

diameter• improved accuracy without standpipe• water interface and product level with

one displacer• average density and density profiling• easy upgradable, low spare parts

costs• unsurpased lightning protection• easy setup, maintenance and repair


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854 Series Servo gauges Conclusions

854 Series Servo gauges Conclusions

• One instrument for:- Level- (Average) Temperature- Interfaces- Density- Level alarms

• Easy installation• Low cost of ownership• Attractive price• Easy to upgrade


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Lightning ProtectionLightning Protection

field side L or R

GDT MOV TZ

suppression

INCORRECT CORRECT

Instrument side field side Instrument side

Diversion

854 ATG General hardware854 ATG General hardware

terminal compartment

electronic compartment

drum compartment

measuring wire

displacer

854 ATGPrinciple block diagram854 ATGPrinciple block diagram

drum motorD U

motorcontrol

weightmeas.

control electr.

forcetrans-ducer

apparent weight

854 ATGServo hardware854 ATGServo hardware

Displacer produces via drum torque on drumshaft

Motor unit fixed on drumshaft

Motor unit applies force to force transducer

Force transducer converts force into frequency

SPU (Servo Processing Unit) receives frequency from force transducer and controls displacer position via motor unit

drum

motor unit drum shaftforce

transducer

transport lock

854 ATGStandard displacers854 ATGStandard displacers

Weight [DW](grams) 223 ± 3 223 ± 3 223 ± 3

Diameter(mm) 45 90 110

Area [DA](cm²) 16 64 95

Volume [DV](cm³) 100 ± 5 100 ± 5 100 ± 5

Material Carbon-PTFE Carbon-PTFE Carbon-PTFEImmersion depth

(at ρ = 0.8 gr/cm³)(mm)

12 ± 2 3 ± 1 2 ± 0.5

depending on application, a

range of displacers is

available, regarding

material, size and

construction

854 ATGMeasuring wire854 ATGMeasuring wire

Material– standard stainless steel– optionally Hasteloy, Tantalum or Invar

Typical– Wire Weight [WW] 0.25 gr/m– diameter 0.2 mm

Important: keep wire free of kinks

Use lug at wire end to attach displacer

Secure and ground displacer

New wire on drum– apply wire with sufficient tension

854 ATGDisplacer attachment854 ATGDisplacer attachment

measuring wire from drumadditional piece (approx. 0.5 m)lugdisplacer

2 or 3 x ≥ 5 x

854 ATGDrum854 ATGDrum

Drum with precise groovesTypical:– drum circumference [DC] engraved on

drum (0,335...0,340 m)– drum error ≤ ± 0.7 mm (calibration report in

instrument packing)– mechanically balanced (≤ 5 mg)– range 27 m (optionally 37 m or higher)– axial travel

– 27 m → 1.5 mm/m– 37 m → 1.0 mm/m

Transport of instrument with drum separatedCheck drum circumferenceCheck axial freeplay (approx. 2 mm)Keep drum, wire and displacer clean

854 ATGMagnet coupling854 ATGMagnet coupling

Typical– 3 pole-pairs– magnet slip at ≥ 1 kg– magnet slip detection [WT] possible– magnet slip coupling correction [CC] & [RM]

Isolates tank atmosphere– safety– pressurized tanks– aggressive products

Protects weighing balance against.....– mechanical shocks and excessive load

Magnet cap– made of non-magnetic material– provided with 2 bearings for full drum support– do not remove magnet cap– keep outer magnet clean and free of (metal) particles

N

NN N

N N

S

S

S

SS

S

854 ATGBearings854 ATGBearings

Made of Carbon-PTFE– conductive because of safety (carbon)

Periodical maintainance– estimated once per 10 years– use genuine parts– 'special tool' required (drum bearing

puller from tool set)

Check bearings by moving drum up/down

854 ATGForce transducer854 ATGForce transducer

Converts force (F) into frequency (f)

Protect force transducer against mechanical shocks– use transport lock during transportation of

instrument

Caution– handle with care– do not readjust any settings

F ↑

f ↓

854 ATGForce transducer854 ATGForce transducer

Each force transducer...– has an individual characteristic– is 100% factory tested

– sensitivity ≥ 8 Hz/g– temp. range -30...+65 °C

Service– [MF] (20 sec) Measure Frequency– [WQ] Weight reQuest– [FQ] Frequency reQuest

↑ force

Apparent weight [g] Output f [kHz]

Range 0-300 11-16

854 ATGGauge calibration854 ATGGauge calibration

250175100250

25 25 25 25

75 150 225

F0

F1

F2F3↑

F [Hz]

S [g] →

[MF]- [FQ]- [WQ]

[BT]- [BF]- [BU]- [BW] - [BV]

854 ATGMotor unit (old)854 ATGMotor unit (old)

Motor unit fixed to drumshaft and force transducer

Motor unit should be free from any other obstacle– check when assembling (e.g. after

repair)

Transportation of instrument– always use transport lock

Check proper operation of motor unit with command [TG]

transportlock

motor unitlocked

motor unitunlocked

854 ATGMotor unit (new)854 ATGMotor unit (new)

Motor unit fixed to drumshaft and force transducer

Motor unit should be free from any other obstacle– check when assembling (e.g. after

repair)

Transportation of instrument– always use transport lock

Check proper operation of motor unit with command [TG]

motor unitlocked

motor unitunlocked

854 ATGReference encoder854 ATGReference encoder

Verifies all movements made by stepper motor

Coded disc is moving through photo-interruptor, generating bit-pattern

Bit-pattern is compared with reference pattern to measure direction and exact number of steps made by stepper motor

Missing motorsteps are detected and automatically corrected

Number of motorstep correction is counted, [ME] ≥ 01

1:34

steppermotor

RE

854 ATGReference encoder errors854 ATGReference encoder errors

Solve error as per description of error code SPU [ES]

Resynchronise reference encoder using 847 PET– type in:

– W2=ENRAF2 (enter password level 2)– SM (Set Maintenance)– FP (Find Position)– SO (Set Operational)– EX (EXit from protection level 2)

– recalibrate level

854 ATGGauge accuracy854 ATGGauge accuracy

Display = accurate level ± level errorLevel error ΔL depends on– gauging platform (e.g. hydrostatic deformation)– instrument accuracy– tank temperature

Instrument accuracy depends on– drum– instrument sensitivity (weighing balance)– wire weight (automatic correction with items [TT] and [WW])– magnet coupling (automatic correction with items [RM] and [CC])– moving parts (can be checked with item [BT])

Instrument accuracy W&M [mm] 854 [mm]drum ≤ 1.4 ≤ 0.5

sensitivity (Δi) ≤ 0.3 ≤ 0.1moving parts ≤ 0.3 ≤ 0.1

TOTAL ≤ 2.0 ≤ 1.0

854 ATGBackplane854 ATGBackplane

Backplane-I or -II– mains voltage selector– 1st slot: XPU (X-mission Processing Unit)– 2nd slot: SPU-I or -II (Servo Processing Unit)– 3rd slot: optional board– 4th slot: GPS (Gauge Power Supply)

All circuit boards are secured via– a retaining screw (screwdriver)– a locking latch on the XPU

Backplane-II fully compatible with backplane-I– backplane-II has additional features/options– backplane-I will become obselete

1st↓

2nd↓

3rd↓

4th↓

mainsvoltageselector

motorunit

forcetrans-ducer

854 ATGBackplane854 ATGBackplane

mains1stslot

2ndslot

3rdslot

4thslot fieldbus

infra red

mainstransformer

or110 V130 V 65 V220 V 240 V240 V

854 ATGXPU-1854 ATGXPU-1

(safety) ground

galvanic isolation(fieldbus)

locking latch(left = locked)

software EPROM

2x16 LCD display

jumpers

NOVRAM

RAM

view angleadjustment

854 ATGXPU-2854 ATGXPU-2

software EPROMNOVRAM

(safety) groundfuture expansion

galvanic isolation(fieldbus)

2x16 LCD display

jumpers

HALL-switches

locking latch(left = locked)

854 ATGXPU854 ATGXPU

NOVRAM– 512 bytes– 1024 bytes (required for HPU/OPU/HSU option)

EEPROM– 32 kB (straps 6 & 7 → 0)– 64 kB (straps 6 & 7 → 1)

NOVRAM

EEPROM

RAM

RAM

EEPROMdefaultsettings

(NOVRAM)

micro-processor

PET-link(infra red)

HOST-link(Bi-Phase Mark)

inter processorcommunication

GPSinterrupts

DISPLAY

TEST(reed switch)

JUMPERS

option I

option II

↓XPU-2 only

854 ATGSPU854 ATGSPU

(safety) ground2c for relais R22c for relais R1

(relais are optional)

R2R1

software EPROM

854 ATGSPU854 ATGSPU

SPU-1– with / without option for servo density measurement

SPU-2– replaces SPU-1– with / without option for alarm relay– with / without option for servo density measurement

Software version Alarm relay Servo densitySPUAn.n N NSPUBn.n Y NSPUCn.n N YSPUDn.n Y Y

854 ATGGPS854 ATGGPS

fuse 250 mA slow

fuse 1 A slow

854 ATGGPS854 ATGGPS

+16 V+12 V

0 V-12 V-16 V+ 5 V

0 V

LPW

65 V~

12 V~

BUFFER

GPScontrol

F11 A/T

F2250 mA/T

IP-RST

SUP-RST

854 ATGSafety aspects854 ATGSafety aspects

Observe local-, company- and certificate requirementsInstallation in hazardous areasProtection methods– explosion proof– increased safe– intrinsically safe

Protective groundingCable entries– 2 x ¾" NPT for non-intrinsic safe cabling– 2 x ¾" NPT for intrinsic safe cabling– use only approved cable glands or conduits

Water ingress protection ≥ IP54Full lightning protection by galvanic isolationModification of any kind NOT allowed

854 ATGSafety aspects854 ATGSafety aspects

A Threaded flame pathB Flat flame pathC Cylindrical flame path

Terminal compartmentexplosion proof

or increased safe(only for zone 1)

Electroniccompartment

explosion proof

Drumcompartment

TANK

AA

A AB

C

grounding

854 ATGPowering up854 ATGPowering up

10

20

30

40

50

60

10-145

GPS MPU SPU XPU sec. POWER ON

GPS: powering up

XPU: NOVRAM-data check & distribution start-up

SPU: reference encoder test/ servo start-up

Note 1: if display does not show I1, but anything else except FL, check [LC]. Issue commands [UN] and [I1] to go to I1

Note 2: Procedure for start-up after reset [RS] or [EX] differs slightly, see [ER]

854 ATGTrouble shooting854 ATGTrouble shooting

Nothing on display (while instrument is installed on tank top*)– switch mains off and on and observe display– check mains voltage level (³ 80% ?)– power off; open covers and check wiring, connectors

check fuse(s) on GPS; replace GPSclose covers and switch power on

– power off; open cover and replace XPU**close cover and switch power on

– power off; open cover and replace EEPROM on XPU***close cover and switch power on

* in safe area (workshop), keep cover open and observe LEDs on circuit boards** use spare XPU without EEPROM; use EEPROM from replaced XPU*** make sure EEPROM is of same version as existing one;

if not, replace complete set of EEPROM (XPU, SPU and ?PU) and reformat NOVRAM

854 ATGOptions (SPU)854 ATGOptions (SPU)

SPU-I– level– water level– soft alarms– option:

– servo density

SPU-II– level– water level– soft alarms– options:

– servo density (density profile)– alarm contacts (hard alarms)– servo density + alarm contacts

854 ATGTest weights (part no. 1854.061)854 ATGTest weights (part no. 1854.061)

Item Weight [g]1 252 753 1504 225

1 2 3 4

18

18

18

≈ 150

≈11

0

≈70

≈85

854 ATGTool set (part no. 1854.062)854 ATGTool set (part no. 1854.062)

Item Description1 Socket head screw wrench 2 mm2 Socket head screw wrench 3 mm3 Socket head screw wrench 4 mm4 Socket head screw wrench 5 mm5 Socket head screw wrench 8 mm6 Drum bearing puller7 Test magnet8 Socket head screwdriver M49 Socket head screwdriver M610 Pipe wrench 27 mm11 Tommy bar

01

02

03

04

05105

85

75

65

50

53

06

07

20

45

09

08

10

11

190

320

335

6.0 Servo Gauges

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