Emerson Fisher 846 Instruction Manual

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Instruction Manual

D102005X012

846 Transducer

Fisherr 846 Current-to-Pressure Transducer

March 2015

Contents

1. Introduction

Scope of Manual 2.............................

Description 2.................................

Specifications 2...............................

Related Documents 5..........................

Educational Services 6.........................

2. Installation Hazardous Area Classifications and Special

Instructions for Safe‐Use and Installation

in Hazardous Locations 7.....................

CSA 8....................................

FM 8.....................................

ATEX 9...................................

IECEx 10..................................

ATEX/IECEx 10............................

Mounting 11.................................

Pressure Connections 11.......................

Supply Pressure 13.........................

Output Pressure 17........................

Electrical Connections 17.......................

Venting Ports 18..............................

Signal Interruption 18..........................

3. Calibration Standard Performance:

Full Range Input, Direct Action 21.............

Multirange Performance:

Full Range Input, Direct Action 21.............

Standard Performance:

Split Range Input, Direct Action 22.............

4 to 12 mA Input Signal 22..................

12 to 20 mA Input Signal 22.................

Standard Performance:

Full Range Input, Reverse Action 23............

Multirange Performance:

Full Range Input, Reverse Action 23............

Standard Performance:

Split Range Input, Reverse Action 24...........

4 to 12 mA Input Signal 24..................

12 to 20 mA Input Signal 24.................

Transporting the Module Final Assembly 25.......

4. Principle of Operation

Electronic Circuit 26...........................

Magnetic Actuator 27..........................

Pilot Stage 27.................................

Booster Stage 28..............................

Figure 1-1. Fisher 846 Current‐to‐Pressure Transducer

X0234

5. Troubleshooting

Diagnostic Features 29.........................

Stroke Port 29.............................

Remote Pressure Reading (RPR) 29...........

Using a Frequency Counter to read the

RPR Signal 29.........................

In‐service Troubleshooting 30...................

Troubleshooting in the Shop 33.................

6. Maintenance

Module Final Assembly 35......................

Removing the Module Final Assembly 38......

Replacing the Module Final Assembly 39.......

Electronic Circuit Board 40......................

Remote Pressure Reading (RPR) Jumper 40.....

Range Jumper 41..........................

Action 41.................................

Removing the Electronic Circuit Board 41......

Replacing the Electronic Circuit Board 42......

Pilot/Actuator Assembly 42.....................

Action 42.................................

Removing the Pilot/Actuator Assembly 43.....

Replacing the Pilot/Actuator Assembly 44.....

Module Subassembly 44........................

Terminal Compartment 44.....................

Exhaust and Stroke Port Screens 45..............

7. Parts 46....................................

8. Installation Drawings 50......................

www.Fisher.com

846 Transducer

March 2015

Instruction Manual

D102005X012

Section 1 Introduction

Scope of Manual

This instruction manual provides installation, operating, calibration, maintenance, and parts ordering information Fisher 846 current‐to‐pressure transducers. Refer to separate manuals for instructions covering equipment used with the transducers.

Do not install, operate or maintain an 846 current‐to‐pressure transducer without being fully trained and qualified in valve, actuator, and accessory installation, operation, and maintenance. To avoid personal injury or property

damage, it is important to carefully read, understand, and follow all of the contents of this manual, including all safety cautions and warnings. If you have any questions about these instructions, contact your Emerson Process

Management sales office before proceeding.

Description

The 846 current‐to‐pressure transducer, shown in figure 1-1, accepts an electrical input signal and produces a proportional pneumatic output. Typically, 4 to 20 mA is converted to 0.2 to 1.0 bar (3 to 15 psi). Models are available in direct or reverse action and field‐selectable full or split range inputs. Refer to the Calibration section for more information on input/output combinations.

The most common application of the transducer is to receive an electrical signal from a controller and produce a pneumatic output for operating a control valve actuator or positioner. The 846 may also be used to transduce a signal for a pneumatic receiving instrument.

The 846 is an electronic I/P transducer. It has a single electronic circuit board, as shown in figure 1-2. The circuit contains a solid‐state pressure sensor that monitors output pressure and is part of an electronic feedback network. The self‐correcting ability provided by the sensor/circuit combination allows the transducer to produce a very stable and responsive output signal.

All active mechanical and electrical components of the 846 are incorporated into a single, field‐replaceable module called the module final assembly, shown in figure 1-2. The module final assembly contains the electronic circuit board, pilot/actuator assembly, and booster stage. The module final assembly is easily removed by unscrewing the module cover. Its design minimizes parts and reduces the time required for repair and troubleshooting.

The terminal compartment and module compartment are separated by a sealed compartment wall. This multi‐compartment housing also protects the electronics from contaminants and moisture in the supply air.

Specifications

WARNING

This product is intended for a specific range of pressures, temperatures, and other application specifications. Applying different pressure, temperature and other service conditions could result in a malfunction of the product, property damage or personal injury.

Specifications for the 846 transducer are listed in table 1-1.

Instruction Manual

D102005X012

Table 1-1. Specifications

846 Transducer

March 2015

Input Signal

Standard Performance:

4 to 20 mA DC, 4 to 12 mA DC, or 12 to 20 mA DC. Field adjustable split ranging.

Multirange Performance:

4 to 20 mA DC. Consult factory for split range input.

Equivalent Circuit

See figure 1-3

Output Signal

(1)

Standard Performance:

(Consult factory for split range output)

Direct Action (Minimum span of 6 psi)

Typical outputs: 0.2 to 1.0 bar (3 to 15 psi). Rangeability between 0.1 and 1.2 bar (1 and 18 psi)

Reverse Action (Minimum span of 11 psi)

Typical outputs: 1.0 to 0.2 bar (15 to 3 psi) Rangeability between 1.2 and 0.1 bar (18 and 1 psi)

Multirange Performance: Direct Action (Minimum span of 6 psi)

Typical outputs: 0.2 to 1.9 bar (3 to 27 psi), 0.4 to 2 bar (6 to 30 psi), and 0.3 to 1.7 bar (5 to 25 psi) Rangeability between 0.03 and 2.3 bar (0.5 and 33 psi)

Reverse Action (Minimum span of 11 psi)

Typical outputs: 1.9 to 0.2 bar (27 to 3 psi), 2 to

0.4 bar (30 to 6 psi), and 1.7 to 0.3 bar (25 to 5 psi) Rangeability between 2.3 and 0.03 bar (33 and

0.5 psi)

Supply Pressure

(2)

Standard Performance: 1.2 to 1.6 bar (18 to 24 psi) Multirange Performance:

0.2 bar (3 psi)

(3)

greater than the maximum

calibrated output pressure Maximum: 2.4 bar (35 psi)

Supply Pressure Medium

Clean, dry air

Per ISA Standard 7.0.01

A maximum 40 micrometer particle size in the air system is acceptable. Further filtration down to 5 micrometer particle size is recommended. Lubricant

-Continued-

content is not to exceed 1 ppm weight (w/w) or volume (v/v) basis. Condensation in the air supply should be minimized

Per ISO 8573-1

Maximum particle density size: Class 7 Oil content: Class 3 Pressure Dew Point: Class 3 or at least 10°C less than

the lowest ambient temperature expected

Output Air Capacity

(4)

Standard: 6.4 m3/hr (240 scfh) at 1.4 bar (20 psi) supply pressure

Multirange: 9.7 m

/hr (360 scfh) at 2.5 bar

(35 psig) supply pressure

Maximum Steady‐State Air Consumption

(4)

0.3 m3/hr (12 scfh) at 1.4 bar (20 psi) supply pressure

Temperature Limits

(2)

Operating: -40 to 85_C (-40 to 185_F) Storage :-40 to 93_C (-40 to 200_F)

Humidity Limits

0 to 100% condensing relative humidity

Performance

(5)

Note: The performance of all 846 I/Ps is verified using computer automated manufacturing systems to ensure that every unit shipped meets its performance specifications.

Linearity, Hysteresis, and Repeatability: $0.3% of span.

Temperature Effect (total effect including zero and span): $0.07%/_C (0.045%/_F) of span

Vibration Effect: $0.3% of span per g during the

following conditions: 5 to 15 Hz at 4 mm constant displacement 15 to 150 Hz at 2 g. 150 to 2000 Hz at 1 g. per SAMA Standard PMC 31.1, Sec. 5.3, Condition 3, Steady State

Shock Effect: $0.5% of span, when tested per SAMA Standard PMC 31.1, Sec. 5.4.

Supply Pressure Effect: Negligible

846 Transducer

March 2015

Table 1-1. Specifications (continued)

Instruction Manual

D102005X012

Performance (continued)

(5)

Electromagnetic Interference (EMI): Tested per IEC 61326‐1 (Edition 1.1). Meets emission levels for Class A equipment (industrial locations) and Class B equipment (domestic locations). Meets immunity requirements for industrial locations (Table A.1 in the IEC specification document). Immunity performance is shown in table 1-2.

Leak Sensitivity

4.8 m

/hr (180 scfh) downstream leakage.

(4)

: Less than 1.0% of span for up to

Overpressure Effect: Less than 0.25% of span for

misapplication of up to 7.0 bar (100 psi) supply pressure for less than 5 minutes to the input port.

Reverse Polarity Protection:

No damage occurs from reversal of normal supply current (4 to 20 mA) or from misapplication of up to 100 mA.

Connections

Supply Air, Output Signal, and Output Gauge: 1/4‐18 NPT internal connection Electrical: 1/2‐14 NPT internal conduit connection

Adjustments

Zero and Span: screwdriver adjustments located in terminal compartment.

Remote Pressure Reading (RPR) Jumper selectable, ON or OFF, if unit includes option

Frequency Range: 0 to 10,000 Hz Amplitude: 0.4 to 1.0 V

p‐p

Required Operating Voltage with Remote pressure Reading Off

Min. 6.0 V (at 4 mA) Max. 7.2 V (at 20 mA)

Required Operating Voltage with Remote Pressure Reading On

Min 6.4 V (at 4 mA) Max. 8.2 V (at 20 mA)

-continued-

Electrical Classification

Hazardous area:

CSA C/US—Intrinsically Safe, Explosion-proof,

Non-Incendive

FM—Intrinsically Safe, Explosion-proof, Non-Incendive

ATEX—Intrinsically Safe, Flameproof, Type n

IECEx—Intrinsically Safe, Flameproof

Refer to Hazardous Area Classifications and Special Instructions for “Safe Use” and Installation in Hazardous Locations in Section 2 for additional information

Electrical Housing:

Tropicalization (Fungus test per MIL-STD-810)

CSA C/US—Type 4X

FM—Type 4X

ATEX—IP66

IECEx—IP66

(6)

Other Classifications/Certifications

INMETRO—National Institute of Metrology, Quality, and Technology (Brazil)

KGS—Korea Gas Safety Corporation (South Korea)

NEPSI— National Supervision and Inspection Centre

for Explosion Protection and Safety of Instrumentation (China)

Contact your Emerson Process Management sales

office for classification/certification specific

information

Construction Materials

Housing: Low‐copper aluminum with polyurethane paint, or 316 stainless steel O‐Rings: Nitrile, except silicone for sensor O‐rings.

Options

Fisher 67CFR filter regulator, supply and output gauges or tire valve remote pressure reading, module cover with multiple stroke ports, stainless steel housing, or stainless steel mounting bracket.

Weight

Aluminum: 2.9 kg (6.5 lb) excluding options Stainless Steel: 6.7 kg (14.8 lb) excluding options

Instruction Manual

D102005X012

Table 1-1. Specifications (continued)

846 Transducer

March 2015

Declaration of SEP

Fisher Controls International LLC declares this product to be in compliance with Article 3 paragraph 3 of the Pressure Equipment Directive (PED) 97 / 23 / EC. It was designed and manufactured in accordance

NOTE: Specialized instrument terms are defined in ANSI/ISA Standard 51.1 - Process Instrument Terminology.

1. Metric calibration also available.

2. The pressure/temperature limits in this document, and any applicable standard or code limitation should not be exceeded.

3. 0.14 bar (2 psi) for a 2.3 bar (33 psi) output.

4. Normal m

5. Reference Conditions: 4.0 to 20 mA DC input, 0.2 to 1.0 bar (3 to 15 psi) output, and 1.4 bar (20 psi) supply pressure.

6. ATEX and IECEx Flameproof — IP66 per CSA Letter of Attestation.

/hr—Normal cubic meters per hour (0_C and 1.01325 bar, absolute). Scfh—Standard cubic feet per hour (60_F and 14.7 psia).

with Sound Engineering Practice (SEP) and cannot bear the CE marking related to PED compliance.

However, the product may bear the CE marking to indicate compliance with other applicable European Community Directives.

Table 1-2. EMC Immunity Performance Criteria

Port Phenomenon Basic Standard Test Level Performance Criteria

Electrostatic discharge (ESD) IEC 61000‐4‐2

Enclosure

I/O signal/control

Specification limit = ±1% of span

1. A = No degradation during testing. B = Temporary degradation during testing, but is self‐recovering.

Radiated EM field IEC 61000‐4‐3

Burst (fast transients) IEC 61000‐4‐4 1 kV A Surge IEC 61000‐4‐5 1 kV (line to ground only, each) B

Conducted RF IEC 61000‐4‐6

4 kV contact 8 kV air

80 to 1000 MHz @ 10V/m with 1 kHz AM at 80% 1400 to 2000 MHz @ 3V/m with 1kHz AM at 80% 2000 to 2700 MHz @ 1V/m with 1kHz AM at 80%

150 kHz to 8 MHz at 3 Vrms B 8 MHz to 80 MHz at 3 Vrms A

(1)

Related Documents

This section lists other documents containing information related to the 846 transducer. These documents include:

D INMETRO Hazardous Area Approvals for Fisher 846 Current-to-Pressure Transducers Instruction Manual

(D103623X012)

D NEPSI Hazardous Area Approvals for Fisher 846 Current-to-Pressure Transducers Instruction Manual

(D103618X012)

All documents are available from your Emerson Process Management sales office. Also visit our website at www.Fisher.com.

846 Transducer

March 2015

Instruction Manual

D102005X012

Figure 1-2. Transducer Modular Construction

TERMINAL COMPARTMENT COVER

TERMINAL BLOCK

MODULE HOUSING

ELECTRONIC CIRCUIT BOARD

MODULE FINAL ASSEMBLY

Figure 1-3. Equivalent Circuit

846

6 V DC

50 OHM S

POWER SUPPLY

NOTE: THE 846 IS NOT A CONSTANT RESISTOR IN SERIES WITH AN INDUCTOR. IT IS BETTER MODELED IN THE LOOP AS A 50 OHM RESISTOR IN SERIES WITH A 6‐VOLT DC VOLTAGE DROP WITH NEGLIGIBLE INDUCTANCE.

A6325

MODULE COVER

A6643

Educational Services

For information on available courses for the 846 current‐to‐pressure transducer, as well as a variety of other products, contact:

Emerson Process Management Educational Services - Registration Phone: +1-641-754-3771 or +1-800-338-8158 Email: education@emerson.com http://www.emersonprocess.com/education

Instruction Manual

D102005X012

846 Transducer

March 2015

Section 2 Installation22

WARNING

To avoid personal injury or property damage from the sudden release of pressure or air:

D Always wear protective clothing, gloves, and eyewear when performing any installation operations.

D Disconnect any operating lines providing air pressure, electric power, or a control signal to the actuator. Be sure the

actuator cannot suddenly open or close the valve.

D Use bypass valves or completely shut off the process to isolate the valve from process pressure. Relieve process pressure

on both sides of the valve.

D Use lock‐out procedures to be sure that the above measures stay in effect while you work on the equipment.

D Check with your process or safety engineer for any additional measures that must be taken to protect against process

media.

This section presents information on installing the 846 current‐to‐pressure transducer. Figures 2-1, 2-2, 2-3, and 2-5 can be used as references for instructions contained in this section.

When a control valve is ordered with a 846 transducer specified to be mounted on the actuator, the factory‐mounted transducer is connected to the actuator with the necessary tubing and calibrated to the specifications on the order.

If the transducer is purchased separately for mounting on a control valve already in service, all the necessary mounting parts are furnished, if ordered. This includes the appropriate bracket for attaching the unit to an actuator boss (with tapped holes) or for attaching it to the diaphragm casing.

If preferred, mounting parts can be supplied for mounting the transducer on a 51 mm (2‐inch) diameter pipestand, a flat surface, or a bulkhead.

Transducers also can be ordered separately for mounting on a control valve assembly already in service. The transducer may be ordered with or without mounting parts. Mounting parts include the appropriate bracket and bolts for attaching the unit to an actuator boss (with tapped holes) or for attaching it to the diaphragm casing.

Hazardous Area Classifications and Special Instructions for “Safe Use” and Installation in Hazardous Locations

Certain nameplates may carry more than one approval, and each approval may have unique installation/wiring requirements and/or conditions of “safe use”. These special instructions for “safe use” are in addition to, and may override, the standard installation procedures. Special instructions are listed by approval.

Note

This information supplements the nameplate markings affixed to the product.

Always refer to the nameplate itself to identify the appropriate certification. Contact your Emerson Process Management sales

office for approval/certification information not listed here.

846 Transducer

March 2015

Instruction Manual

D102005X012

WARNING

Failure to follow these conditions of safe‐use could result in personal injury or property damage from fire or explosion, and area re‐classification.

CSA

Intrinsically Safe, Explosion-proof, Non-Incendive

No special conditions for safe use.

Refer to table 2-1 for approval information.

Table 2-1. Hazardous Area Classifications for Canada—cCSAus

Certification Body Certification Obtained Entity Rating Temperature Code

Vmax = 30 VDC Imax = 100 mA Ci = 0.016 mF Li = 20 mH

- - - T4 (Tamb ≤ 60_C)

T4 (Tamb ≤ 60_C)

CSA

Ex ia Intrinsically Safe Class I Division 1 Groups A,B,C,D T4 per drawing GE59146 (see figure 8-1)

XP Explosion-proof Class I Division 1 Groups C,D DIP Dust Ignition-proof Class II III Division I Groups E,F,G T4 NI Non-incendive Class I, Division 2, Groups A,B,C,D T4

Special Conditions of Use

Intrinsically Safe, Explosion-proof, Non-Incendive

1. The apparatus enclosure contains aluminum and is considered to constitute a potential risk of ignition by impact or friction. Care must be taken into account during installation and use to prevent impact or friction.

Refer to table 2-2 for additional approval information.

Table 2-2. Hazardous Area Classification for United Stated—FM

Certification Body Certification Obtained Entity Rating Temperature Code

Vmax = 30 VDC Imax = 100 mA Pmax = 1.0 W Ci = 0.016 mF Li = 20 mH

- - - T4 (Tamb ≤ 60_C)

T4 (Tamb ≤ 60_C)

IS Intrinsically Safe Class I, II, III Division 1 Groups A,B,C,D,E,F,G per drawing GE59147 (see figure 8-2)

XP Explosion-proof Class I Division 1 Groups B,C,D DIP Dust Ignition-proof Class II, III Division I Groups EFG NI Non-incendive Class I Division 2 Groups A,B,C,D

Instruction Manual

D102005X012

846 Transducer

March 2015

ATEX

Special Conditions for Safe Use

Intrinsically Safe

This equipment is intrinsically safe and can be used in potentially explosive atmospheres.

The apparatus must be only connected to a certified associated intrinsically safe equipment and this combination must be compatible as regards intrinsic safety rules.

The electrical parameters of certified equipment which can be connected to the sensor must not exceed one of these following values:

≤ 30 V

≤ 100 mA

≤ 1.0 W

Ambient temperature: -40_C to +80_C

Flameproof

Refer to page 10.

Type n

No special conditions for safe use.

Refer to table 2-3 for additional approval information.

Table 2-3. Hazardous Area Classifications—ATEX

Certificate Certification Obtained Entity Rating Temperature Code

Intrinsically Safe II 1 GD Gas Ex ia IIC T4,T5 Ga Dust Ex ia IIIC IP66 Da T90_C (Tamb ≤ 80_C) Ex ia IIIC IP66 Da T50_C (Tamb ≤ 40_C)

Flameproof

ATEX

II 2 G Gas Ex d IIB T5/T6 Gb

Type n II 3 GD Gas Ex nA IIC T5/T6 Gc Dust Ex tc IIIC T88_C T Ex tc IIIC T77_C T

500 500

Dc IP66 Dc IP66

Ui = 30 VDC Ii = 100 mA Pi = 1.0 W Ci = 8 nF Li = 20 mH

- - -

T4 (Tamb ≤ 80_C) T5 (Tamb ≤ 40_C)

T5 (Tamb ≤ 80_C) T6 (Tamb ≤ 65_C)

T5 (Tamb ≤ 85_C) T6 (Tamb ≤ 74_C)

846 Transducer

March 2015

IECEx

Special Conditions for Safe Use

Intrinsically Safe

No special conditions for safe use.

Flameproof

See below.

Refer to table 2-4 for additional approval information.

Table 2-4. Hazardous Area Classifications—IECEx

Certificate Certification Obtained Entity Rating Temperature Code

Intrinsically Safe Gas Ex ia IIC T4/T5 Ga

IECEx

Flameproof Gas Ex d IIB T5/T6 Gb

Ui = 40 VDC Ii = 200 mA Pi = 1.0 W Ci = 8 nF Li = 20 mH

- - -

Instruction Manual

D102005X012

T4 (Tamb ≤ 80_C) T5 (Tamb ≤ 40_C)

T5 (Tamb ≤ 80_C) T6 (Tamb ≤ 65_C)

ATEX/IECEx

Special Conditions for Safe Use

Flameproof

1. The equipment incorporates flameproof joints which have a maximum gap less than that stated in EN 60079‐1. The user shall refer to the manufacturer's installation, operation, and maintenance document for guidance.

2. The cable entry device used shall be certified Ex d IIB or Ex d IIC.

3. The user shall ensure that the maximum system pressure does not exceed 35 psi.

4. Refer to figures 2-2 and 2-3 for proper bolting engagement length for ATEX and IECEx flameproof units.

5. A cable entry hole is provided for the accommodation of a flameproof cable entry device, with or without the interposition of a flameproof thread adaptor.

For ATEX certified versions of 846 transducers—the cable entry device and thread adapter shall be suitable for the equipment, the cable and the conditions of use and shall be certified as Equipment (not a Component) under an EC Type Examination Certificate to Directive 94/9/EC. Refer to table 2-3 for additional approval information.

For IECEx certified versions of 846 transducers—the cable entry device and thread adapter shall be suitable for the equipment, the cable and the conditions of use and shall be certified as Equipment (not a Component). Refer to table 2-4 for additional approval information.

Instruction Manual

D102005X012

846 Transducer

March 2015

Mounting

WARNING

This unit will vent to the atmosphere through the stroke port in the module cover and the exhaust port, located under the nameplate. Do not remote vent this unit.

The transducer is designed for mounting on a control valve, 51 mm (2‐inch) diameter pipestand, wall, or panel. Figures 2-2, 2-3, 2-4, and 2-5 show recommended mounting configurations. The mounting positions shown allow any moisture buildup in the terminal compartment to drain to the signal wire conduit entrance. Any moisture in the pilot stage area will be expelled through the stroke port without affecting pilot stage operation. In applications with excessive moisture in the supply air, vertical mounting allows the most effective drainage through the stroke port.

CAUTION

Do not mount the transducer with the terminal compartment cover on the bottom as moisture, or any corrosive elements in the plant atmosphere, may accumulate in the terminal compartment or pilot stage, resulting in transducer malfunction.

Mounting is accomplished with an optional universal mounting bracket. Before mounting the transducer, note the following recommendations:

D Ensure that all bolts are fully tightened. The recommended torque is 22 NSm (16 lbfSft).

D Bolts that connect to the transducer and to a valve actuator should have the lock washer placed directly beneath the

bolt head and the flat washer placed between the lock washer and bracket. All other bolts should have the lock washer next to the nut, and the flat washer placed between the lock washer and bracket.

D Do not mount the transducer in a location where foreign material may cover the stroke port or exhaust port. See the

descriptions of the stroke port and exhaust port later in this section.

Pressure Connections

As shown in figure 2-1, all pressure connections are 1/4‐18 NPT internal connections. Use 9.5 mm (3/8‐inch) outside diameter tubing for the supply and output connections.

846 Transducer

March 2015

Instruction Manual

D102005X012

Figure 2-1. Typical Dimensions and Connection Locations (Aluminum Construction Shown)

129

(5.07)

119

STROKE PORT

(4.68)

MODULE COVER WITH

MULTIPLE PORTS

NAMEPLATE

MOUNTING BOLT HOLES 5/16‐18 (3)

EXHAUST PORT UNDERNEATH NAMEPLATE

(2.31)

CONDUIT CONNECTION 1/2 ‐ 14 NPT

OUTPUT PORT 1/4 ‐ 18 NPT

(1.38)

(1.13)

(1.16)

COVER REMOVAL

OUTPUT GAUGE PORT 1/4‐18 NPT

TEST PINS

WIRING CONNECTION

NOTE:

REFER TO FIGURE 2-5 FOR TRANSDUCER DIMENSIONS WITH ATEX / IECEx FLAMEPROOF CERTIFICATIONS

B2473‐1

POSITIVE NEGATIVE INTERNAL GROUND

110

(4.33)

102

(4.00)

O‐RING GROOVE FOR FILTER REGULATOR

SUPPLY PORT 1/4‐18 NPT

5/16‐18 (2)

(INCHES)

Instruction Manual

D102005X012

846 Transducer

March 2015

Supply Pressure

WARNING

Severe personal injury or property damage may occur from process instability if the instrument supply medium is not clean, dry air. While use and regular maintenance of a filter that removes particles larger than 40 micrometers in diameter will suffice in most applications, check with an Emerson Process Management field office and industry instrument air quality standards if you are unsure about the proper amount or method of air filtration or filter maintenance.

The supply medium must be clean, dry air that meets the requirements of ISA Standard 7.0.01 or ISO 8573-1. An output span of 0.2 to 1.0 bar (3 to 15 psi) requires a nominal supply pressure of 1.4 bar (20 psi) and a flow capacity not less than 6.4 normal m

For multirange performance units with higher output spans, the supply pressure should be at least 0.2 bar (3 psi) greater than the maximum calibrated output pressure.

The air supply line can be connected to the 1/4‐18 NPT supply port, or to the supply port of a filter‐regulator mounted directly to the transducer. Figures 2-2, 2-3, 2-4, and 2-5 show the installation options.

/hr (240 scfh).

Figure 2-2. Typical Dimensions with Fisher 67CFR Filter/Regulator and Gauges

215 COVER REMOVAL CLEARANCE

NOTE: 1 THE MOUNTING POSITIONS SHOWN ALLOW ANY MOISTURE BUILDUP IN THE TERMINAL COMPARTMENT TO DRAIN TO THE SIGNAL WIRE CONDUIT ENTRANCE. DO NOT MOUNT THE TRANSDUCER WITH THE TERMINAL COMPARTMENT COVER ON THE BOTTOM; MOISTURE MAY ACCUMULATE IN THE TERMINAL COMPARTMENT OR PILOT STAGE, PREVENTING PROPER TRANSDUCER OPERATION. THE VERTICAL MOUNT IS MOST EFFECTIVE FOR MOISTURE DRAINAGE IN WET APPLICATIONS.

14B7361‐D A6626-3

(2.62)

(3.08)

156

(6.15)

(8.48)

CENTERLINE OF ACTUATOR

YOKE MOUNTED

(0.25)

FOR PROPER MOISTURE DRAINAGE THIS END MUST BE UP

191

(7.51)

MODULE COVER REMOVAL CLEARANCE

(0.50)

FOR ATEX/IECEx FLAMEPROOF UNITS: BOLT ENGAGEMENT NOT TO EXCEED

137

12.9 mm (0.51 INCHES).

(5.38)

5/16‐18 BOLTS

(INCH)

846 Transducer

March 2015

Figure 2-3. Typical Transducer Mounting with Universal Mounting Bracket

Instruction Manual

D102005X012

ADDITIONAL ADAPTER PLATE PART NUMBER 03311‐0318‐0001 REQUIRED FOR I/P WITH STAINLESS STEEL HOUSING

U BOLT

5/16‐18 x 5/8 BOLTS

ADAPTER PLATE (SEE DETAIL “B”)

(1.61)

VERTICAL MOUNT

MOUNTING BRACKET (SEE DETAIL “A”)

FOR PROPER MOISTURE DRAINAGE, THIS END MUST BE UP

5/16‐18 HEX NUT (4 PLACES)

2‐INCH PIPESTAND MOUNTING

FOR ATEX/IECEx FLAMEPROOF UNITS: BOLT ENGAGEMENT NOT TO EXCEED 8.8 mm (0.35 INCHES). 5/16‐18 BOLT HOLES

MOUNTING BRACKET (SEE DETAIL “A”)

ADAPTER PLATE (SEE DETAIL “B”)

FOR ATEX/IECEx FLAMEPROOF UNITS: BOLT ENGAGEMENT NOT TO EXCEED

8.1 mm (0.32 INCHES). 5/16‐18 BOLT HOLES

HORIZONTAL MOUNT

FOR PROPER MOISTURE DRAINAGE, THE I/P MUST BE MOUNTED ON TOP OF THE PIPE

ADDITIONAL ADAPTER PLATE PART NUMBER 03311‐0318‐0001 REQUIRED FOR I/P WITH STAINLESS STEEL HOUSING

5/16‐18 x 3/4 BOLTS (4 PLACES)

MOUNTING BRACKET (SEE DETAIL “A”)

FOR PROPER MOISTURE DRAINAGE, THIS END MUST BE UP

GE06214 SHT 3

BOLT HOLES FOR STAINLESS

STEEL CONSTRUCTION

(COVERLOCK SHOWN)

GE06214 SHT 2

BOLT HOLES FOR ALUMINUM

CONSTRUCTION (COVERLOCK SHOWN)

NOTES: 1 THE MOUNTING POSITIONS SHOWN ALLOW ANY MOISTURE BUILDUP IN THE TERMINAL COMPARTMENT TO DRAIN TO THE SIGNAL WIRE CONDUIT ENTRANCE. DO NOT MOUNT THE TRANSDUCER WITH THE TERMINAL COMPARTMENT COVER ON THE BOTTOM; MOISTURE MAY ACCUMULATE IN THE TERMINAL COMPARTMENT OR PILOT STAGE, PREVENTING PROPER TRANSDUCER OPERATION. THE VERTICAL MOUNT IS MOST EFFECTIVE FOR MOISTURE DRAINAGE IN WET APPLICATIONS. 2 IF MOUNTED ON HORIZONTAL PIPE, THE I/P MUST BE ON TOP OF THE PIPE FOR PROPER MOISTURE DRAINAGE. 3 THIS DIMENSION IS 44 (1.74) FOR STAINLESS STEEL HOUSING.

14B7332 19B9484‐B E0786

(1.25)

WALL/PANEL MOUNTING

(ALUMINUM HOUSING)

mm (INCH)

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Figure 2-3. Typical Transducer Mounting with Universal Mounting Bracket (continued)

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March 2015

4 X 10 (0.375)

(1.18)

5 X 10 (0.375)

U‐BOLT SLOTS 19 (0.75)

(1.13)

(1.50)

(3.50)

(1.16)

(2.312)

(.89)

(3.50)

FOR ALUMINUM HOUSING, ALIGN 3 HOLES WITH I/P HOUSING

DETAIL “A” MOUNTING BRACKET

(1.125

(2.25)

U‐BOLT SLOTS 19 (0.75)

FOR STAINLESS STEEL HOUSING, ALIGN 4 HOLES WITH I/P HOUSING

(1.50)

(1.125

(2.25)

2 X 10 (0.375)

03311-0318

4 X 5 (0.188)

2 X 10 (0.375)

DETAIL “B” ADAPTER PLATE

4 X 5 (0.188)

mm (INCH)

ADDITIONAL ADAPTOR PLATE (PART NUMBER 03311‐0318‐0001)

NOTES:

1. ATTACH THE BRACKET SHOWN IN DETAIL “A” TO THE TRANSDUCER

2. ATTACH THE ADAPTER PLATE SHOWN IN DETAIL “B” TO THE VALVE OR PIPE.

3. CONNECT THE TWO PIECES.

34B4990‐C 34B5000‐B E0787

REQUIRED FOR I/P WITH STAINLESS STEEL HOUSING

The mounting boss for the air supply connection contains two 5/16‐18 UNC tapped holes that are 2‐1/4 inches apart. The tapped holes allow direct connection (integral mount) of a 67CFR filter‐regulator, if desired. When the filter‐regulator is factory mounted, the mounting hardware consists of two 5/16‐18 x 3‐1/2 inch stainless steel bolts and one O‐ring. When the filter‐regulator is field mounted, the mounting hardware consists of two 5/16‐18 x 3‐1/2 inch stainless steel bolts, two spacers (which may or may not be required) and two O‐rings (of which only one will fit correctly into the housing O‐ring groove and the other may be discarded). This is due to the fact that the current housing has been slightly modified from its original design, hence, the additional hardware (if needed) when field mounting the 67CFR filter‐regulator.

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Figure 2-4. Typical Transducer Dimensions with Gauges

OUTPUT GAGE

FILTER‐ REGULATOR

SUPPLY GAGE

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(3.2)

14B7332‐D E0776

(1.92)

(2.83)

67CFR 14‐18 NPT SUPPLY CONN

(0.36)

Figure 2-5. Transducer Dimensions with ATEX / IECEx Flameproof Certifications

EXTERNAL EARTHING CONNECTION, SST TERMINAL CLAMP AND SLOTTED M5 SCREW AND SPLIT RING WASHER

TERMINAL COMPARTMENT COVER

3.62 (92)

COVER LOCK

1/4‐18 NPT OUTLET CONN PLUGGED WHEN GAUGE NOT FURNISHED

162

(6.38)

(INCH)

B2465

INTERNAL HEX DRIVE ROUND HEAD SCREW (3 mm)

4.75

(121)

HOUSING

129

(5.07)

MODULE COVER

121

(4.75)

(INCH)

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March 2015

Output Pressure

Connect the output signal line to the transducer at the output port. The output port is 1/4‐18 NPT, as shown in figure 2-1. The output gauge port can be used as an alternate signal port. If the gauge port is used as a signal port, a threaded plug must be installed in the output port.

The output gauge port allows connection of an output gauge to provide local output signal indication. The output gauge port is 1/4‐18 NPT. If an output gauge is not specified, a threaded plug is shipped with the transducer. The plug must be installed in the output gauge port when the port is not used.

Electrical Connections

WARNING

Personal injury or property damage could result from fire or explosion. In explosive atmospheres, remove power and shut off the air supply to the I/P unit before attempting to remove the terminal compartment cover or module cover. Failure to do so could result in an electrical spark or explosion.

Personal injury or property damage could result from an uncontrolled process. Unscrewing the module cover removes power from the electronics and the output signal will be 0.0 psi. Perform the steps in the WARNING at the beginning of this section before removing the module cover to ensure the process is properly controlled.

CAUTION

Excessive current can damage the transducer. Do not connect an input current of more than 100 mA to the transducer.

Note

For North American explosion‐proof applications, 846 transducers have been designed so that a conduit seal is not required. For all other applications install the product per local, regional, or national code, rules, and regulations.

WARNING

Select wiring and/or cable glands that are rated for the environment of use (such as hazardous location, ingress protection, and temperature). Failure to use properly rated wiring and/or cable glands can result in personal injury or property damage from fire or explosion.

Signal wiring is brought to the terminal compartment through a 1/2‐14 NPT housing conduit connection, shown in figure 2-1. Where condensate is common, use a conduit drip leg to help reduce liquid buildup in the terminal compartment and avoid shorting of the input signal. Electrical connections are made at the terminal block. Internal and external grounding lugs are provided to facilitate a separate ground when required. The internal ground is shown in figure 2-1, and the external grounding lug is shown in figure 2-5.

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Connect the positive signal lead to the positive terminal, marked +. Connect the negative signal lead to the negative terminal, marked -.

Note

Units with the Remote Pressure Reading (RPR) option may cause interference with the analog output signal from some instrumentation systems. This problem may be solved by placing a 0.2 microfarad capacitor or a HART filter across the output terminals.

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Venting Ports

WARNING

This unit will vent to the atmosphere through the stroke port in the module cover and the exhaust port, located under the nameplate. Do not remote vent this unit.

Stroke Port

The constant bleed of supply medium from the pilot stage is directed out the stroke port, which is a screened hole located at the center of the module cover. Figure 2-1 shows the location of the stroke port.

Before installing the transducer, ensure the stroke port is clear. Do not mount the transducer in a location where foreign material may cover the stroke port. For information on using the stroke port, refer to the Troubleshooting section.

Exhaust Port

The transducer exhausts through a screened port located beneath the instrument nameplate. Figure 2-1 shows the location of the exhaust port. The nameplate holds the screen in place. Exhaust will occur with a reduction in output pressure. The transducer should not be mounted in a location where foreign material may clog the exhaust port.

Signal Interruption

Upon loss of input current, or if input current decreases below 3.3 $0.3 mA, the output of the direct action unit will decrease to less than 0.1 bar (1 psi).

In the same situation, the output of the reverse action unit will increase to near supply pressure.

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March 2015

Section 3 Calibration33

WARNING

The following calibration procedures require taking the transducer out of service. To avoid personal injury and property damage caused by an uncontrolled process, provide some temporary means of control for the process before taking the transducer out of service. Also refer to the WARNING at the beginning of the Maintenance section.

Calibration of the 846 requires either an accurate current generator or an accurate voltage generator with a precision 250‐ohm, 1/2‐watt resistor. Figure 3-1 shows how to connect either device.

Calibration also requires a precision output indicator and a minimum non-surging air supply of 5.0 normal m (187 scfh) at 1.4 bar (20 psi) for standard performance units. For multirange performance units, the air supply must be at least 0.2 bar (3 psi) greater than the maximum calibrated output pressure, up to 2.4 bar (35 psi) maximum.

/hr

For ease of calibration, the output load volume, including the output tubing and output indicator, should be a minimum of 33 cm

(2 cubic inches). Review the information under Signal Interruption in the Installation section

before beginning the calibration procedure.

Before calibration, determine the type of input (full or split range), and the type of output action (direct or reverse). Consult the factory for split range output calibration. Also, determine if the unit offers standard or multirange performance. The unit supports eight basic input/output combinations:

Standard Performance

D Full Range Input, Direct Action

D Split Range Input, Direct Action

D Full Range Input, Reverse Action

D Split Range Input, Reverse Action

Multirange Performance

D Full Range Input, Direct Action

D Split Range Input, Direct Action (see note below)

D Full Range Input, Reverse Action

D Split Range Input, Reverse Action (see note below)

Note

Consult your Emerson Process Management sales office range input or split range output, or both.

or the factory for calibration of multirange performance units with split

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Figure 3-1. Connecting a Current or Voltage Source for Calibration

TO OBTAIN THE 4 AND 20 mA SET POINTS, ADJUST THE

VOLTAGE SOURCE (V ADJUST THE CURRENT SOURCE TO PROVIDE THE 4 AND 20 mA SET POINTS

THE VOLTMETER (V

1 AND 5 VOLTS, RESPECTIVELY,

ACROSS THE 250 ohm RESISTOR

) SO

) READS

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A6644‐1

CALIBRATION USING A CURRENT SOURCE

CALIBRATION USING A VOLTAGE SOURCE

CAUTION

Excessive current can damage the transducer. Do not connect an input current of more than 100 mA to the transducer.

Table 3-1 lists the various input and output ranges over which the unit may be calibrated.

The input range is selected by changing the position of a jumper located on the electronic circuit board.

Refer to Electronic Circuit Board in the Maintenance section, and figure 6-4 for the location and instruction on placement.

Table 3-1. Fisher 846 I/P Rangeability Matrix

Output Pressure Range (psi) (Performance Code)

Input

Range

3-15

(S,M)

4-20 n n n n n D n D D n U U n U n U

Common Ranges Misc. Std. Split High Range Splits

.5-30

(M)

3-27

(M)

6-30

(M)

5-25

(M)

0.5-6 (S,M)

.5-18 (S,M)

3-9

(S,M)

9-15

(S,M)

.5-15

(S,M)

15-30

(M)

15-27

(M)

6-18

(S,M)

18-30

(M)

5-15

(S,M)

15-25

(M)

4-12

12-20nn

4-8

8-12 12-16 16-20

S=Standard Performance Unit M=Multirange Performance Unit n=Available in Direct or Reverse Action D=Available in Direct Action Only J=Available, but if the desired calibration cannot be achieved by adjusting the zero/span screws, unit may require Hi/Lo jumper to be moved. The jumper is located on the circuit board assembly, and is usually in the Hi position. Disengaging the master module and moving the jumper to the Lo position will allow calibration to the desired range. U=Special Build Required.

n n

J J

n n

J J

n n

J J

n n n

n n

J J

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Standard Performance: Full Range Input, Direct Action

WARNING

Refer to the WARNING at the beginning of the Maintenance section.

Use the following procedure to achieve a standard 0.2 to 1.0 bar (3 to 15 psi) output span for a 4 to 20 mA input signal:

1. Remove the module final assembly from the housing. Refer to Removing the Module Final Assembly in the Maintenance section for an explanation of how to disengage the module final assembly.

2. Confirm that the unit is direct acting. A green electronic circuit board identifies direct‐acting units. Refer to Action under the heading Electronic Circuit Board in the Maintenance section for more information on direct acting units.

3. Position the range jumper in the Hi position for High Range. Figure 6-4 shows the circuit board jumper positions.

4. Replace the module final assembly in the housing. Refer to Replacing the Module Final Assembly in the Maintenance section for an explanation of how to engage the module final assembly.

5. Connect the air supply to the air supply port.

6. Connect a precision output indicator to the output signal port.

7. Make sure that the output gauge port has an output gauge or a threaded plug installed. A threaded plug is provided for units shipped without output gauges.

8. Remove the terminal compartment cover.

9. Connect the current source (or voltage source) positive lead (+) to the terminal block positive (+) and the current source (250‐ohm resistor lead) negative lead (-) to the terminal block negative (-). Refer to figure 3-1.

CAUTION

Excessive current can damage the transducer. Do not connect an input current of more than 100 mA to the transducer.

10. Apply a 4.0 mA (Vm = 1.0 V) signal, and adjust the zero screw to achieve a 0.2 bar (3.0 psi) output. The output increases with clockwise rotation of the zero screw.

11. Apply a 20.0 mA (Vm = 5.0 V) signal, and adjust the span screw to achieve a 1.0 bar (15.0 psi) output. The output increases with clockwise rotation of the span screw.

12. Repeat steps 10 and 11 to verify and complete the calibration.

Multirange Performance: Full Range Input, Direct Action

WARNING

Refer to the WARNING at the beginning of the Maintenance section.

Note

Consult your Emerson Process Management sales office range input.

or the factory for calibration of multirange performance units with split

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Use the following procedure with a multirange performance unit to achieve the desired direct action output span for a 4 to 20 mA input signal:

1. Perform steps 1 through 9 of the calibration procedure for Standard Performance: Full Range Input, Direct Action.

2. Apply a 4.0 mA (Vm = 1.0 V) signal, and adjust the zero screw to achieve the desired lower limit of the output range. The lower limit must be between 0.03 and 0.6 bar (0.5 and 9.0 psi). The output increases with clockwise rotation of the zero screw.

3. Apply a 20.0 mA (Vm = 5.0 V) signal, and adjust the span screw to achieve the desired upper limit of the output range. The span must be at least 0.4 bar (6.0 psi). The maximum upper limit is 2.0 bar (30.0 psi). The output increases with clockwise rotation of the span screw.

4. Repeat steps 2 and 3 to verify and complete the calibration.

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Standard Performance: Split Range Input, Direct Action

WARNING

Refer to the WARNING at the beginning of the Maintenance section.

4 to 12 mA Input Signal

Use the following calibration procedure to produce a 0.2 to 1.0 bar (3 to 15 psi) output span for a 4 to 12 mA input signal:

1. Perform steps 1 through 9 of the calibration procedure for Standard Performance: Full Range Input, Direct Action.

2. Apply an input of 4.0 mA (Vm = 1.0 V), and adjust the zero screw to achieve an output of 0.2 bar (3.0 psi).

3. Apply an input of 12.0 mA (Vm = 3.0 V), and adjust the span screw to achieve an output of 1.0 bar (15.0 psi).

4. Repeat steps 2 and 3 to verify and complete the calibration.

12 to 20 mA Input Signal

Use the following calibration procedure to produce a 0.2 to 1.0 bar (3 to 15 psi) output span for a 12 to 20 mA input signal:

Note

There may be some span interaction with zero in this range, and the following steps compensate for this.

1. Perform steps 1 through 9 of the calibration procedure for Standard Performance: Full Range Input, Direct Action.

2. Apply an input of 4.0 mA (Vm = 1.0 V), and adjust the zero screw to achieve an output of 0.2 bar (3.0 psi).

3. Apply an input of 12.0 mA (Vm = 3.0 V), and adjust the span screw to achieve an output of 1.0 bar (15.0 psi).

4. Maintain the input of 12.0 mA (Vm = 3.0 V), and adjust the zero screw to achieve an output of 0.2 bar (3.0 psi). The unit may not turn down this low; if it does not, go to step 7.

5. If the output reaches 0.2 bar (3.0 psi) in step 4, apply an input of 20.0 ma (Vm = 5.0 V) and note the error (the actual reading versus 15.0 psi). Adjust the span screw to overcorrect the error by a factor of two. For example, if the reading was 0.9 bar (14.95 psi), adjust the span screw to achieve an output of 1.1 bar (15.05 psi).

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6. Repeat steps 4 and 5 to verify and complete the calibration.

7. Turn off the air supply. Remove the module final assembly from the housing. Place the range jumper in the Lo position for Low Range, as indicated in figure 6-4. Replace the module final assembly. Turn on the air supply.

8. Apply an input of 12.0 mA (Vm = 3.0 V), and adjust the zero screw to achieve an output of 0.2 bar (3.0 psi).

9. Apply an input of 20.0 mA (Vm = 5.0 V), and note the error (the actual reading versus 15.0 psi). Adjust the span screw to overcorrect the error by a factor of two. For example, if the reading was 0.9 bar (14.95 psi), adjust the span screw to achieve an output of 1.1 bar (15.05 psi).

10. Repeat steps 8 and 9 to verify and complete the calibration.

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Standard Performance: Full Range Input, Reverse Action

WARNING

Refer to the WARNING at the beginning of the Maintenance section.

Use the following procedure on reverse action units to achieve a 1.0 to 0.2 bar (15 to 3 psi) output span for a 4 to 20 mA input signal:

1. Perform steps 1 through 9 under Standard Performance: Full Range Input, Direct Action, except for step 2. In place of step 2, confirm that the unit is reverse acting. A red electronic circuit board identifies reverse‐acting units. Refer to Action acting units.

2. Apply an input of 4.0 mA (Vm = 1.0 V), and adjust the zero screw to achieve an output of 1.0 bar (15.0 psi).

3. Apply an input of 20.0 mA (Vm = 5.0 V), and adjust the span screw to achieve an output of 0.2 bar (3.0 psi).

4. Repeat steps 2 and 3 to verify and complete the calibration.

under the heading Electronic Circuit Board in the Maintenance section for more information on reverse

Multirange Performance: Full Range Input, Reverse Action

WARNING

Refer to the WARNING at the beginning of the Maintenance section.

Note

Consult your Emerson Process Management sales office range input.

Use the following procedure with a multirange unit to achieve the desired reverse action output span for a 4 to 20 mA input signal:

or the factory for calibration of multirange performance units with split

1. Perform steps 1 through 9 of the calibration procedure for Standard Performance: Full Range Input, Direct Action, except for step 2. In place of step 2, confirm that the unit is reverse acting. A red electronic circuit board identifies reverse‐acting units. Refer to Action under the heading Electronic Circuit Board in the Maintenance section for more information on reverse acting units.

2. Apply an input of 4.0 mA (Vm = 1.0 V), and adjust the zero screw to achieve the desired upper limit of the output range. The 4 mA point must be between 0.6 and 2.0 bar (9.0 and 30.0 psi). The output increases with clockwise rotation of the zero screw.

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3. Apply an input of 20.0 mA (Vm = 5.0 V), and adjust the span screw to achieve the desired lower limit of the output range. The span must be at least 0.7 bar (11.0 psi). The lower limit of the 20.0 mA setting is 0.03 bar (0.5 psi). The output increases with clockwise rotation of the span screw.

4. Repeat steps 2 and 3 to verify and complete the calibration.

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Standard Performance: Split Range Input, Reverse Action

WARNING

Refer to the WARNING at the beginning of the Maintenance section.

4 to 12 mA Input Signal

Use the following procedure on reverse action units to achieve a 1.0 to 0.2 bar (15 to 3 psi) output signal for a 4 to 12 mA input signal:

2. Apply an input of 4.0 mA (Vm = 1.0 V), and adjust the zero screw to achieve an output of 1.0 bar (15.0 psi).

3. Apply an input of 12.0 mA (Vm = 3.0 V), and adjust the span screw to achieve an output of 0.2 bar (3.0 psi).

4. Repeat steps 2 and 3 to verify and complete the calibration.

12 to 20 mA Input Signal

Use the following procedure on reverse action units to achieve a 1.0 to 0.2 bar (15 to 3 psi) output signal for a 12 to 20 mA input signal:

Note

There may be some span interaction with zero in this range, and the following steps compensate for this.

1. Perform steps 1 through 9 of the calibration procedure for Standard Performance: Full Range Input, Direct Action, except for step 2. In place of step 2, confirm that the unit is reverse action. A red electronic circuit board identifies reverse‐acting units. Refer to Action under the heading Electronic Circuit Board in the Maintenance section for more information on reverse acting units.

2. Apply an input of 4.0 mA (Vm = 1.0 V), and adjust the zero screw to achieve an output of 1.0 bar (15.0 psi).

3. Apply an input of 12.0 mA (Vm = 3.0 V), and adjust the span screw to achieve an output of 0.2 bar (3.0 psi).

4. Maintain the input of 12.0 mA (Vm = 3.0 V), and adjust the zero screw to achieve an output of 1.0 bar (15.0 psi). The unit may not turn up this high; if it does not, go to step 7.

5. If the output reaches 15.0 psi in step 4, apply an input of 20 mA, and adjust the span screw to achieve a 3.0 psi output. Apply an input of 20 mA (Vm = 5.0 V), and note the error (the actual reading versus 3.0 psi). Adjust the span screw to overcorrect the error by a factor of two. For example, if the reading was 2.95 psi, adjust the span screw to achieve an output of 3.05 psi.

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6. Repeat steps 4 and 5 to verify and complete the calibration.

7. If the 12.0 mA (Vm = 3.0 V) cannot be adjusted to 1.0 bar (15.0 psi) in step 4, turn off the air supply. Remove the module final assembly from the housing. Place the range jumper in the Lo position for Low Range, as shown in figure 6-4. Replace the module final assembly. Turn on the air supply.

8. Apply an input of 12.0 mA (Vm = 3.0 V), and adjust the zero screw to achieve an output of 1.0 bar (15.0 psi).

9. Apply an input of 20 mA (Vm = 5.0 V), and note the error (the actual reading versus 3.0 psi). Adjust the span screw to overcorrect the error by a factor of two. For example, if the reading was 2.95 psi, adjust the span screw to achieve and output of 3.05 psi.

10. Repeat steps 8 and 9 to verify and complete the calibration.

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Transporting the Module Final Assembly

The transducer allows the module final assembly to be removed while the housing is in its installed position. In the event the transducer does not function properly, an operational module final assembly can be taken to the field and exchanged with the nonfunctional module.

After the transducer is calibrated in the shop, the module final assembly can be removed from the housing. At the time the span and zero screws disengage, there will be minimal effect on the calibrated span. The calibrated module can now be taken to the field. Ensure that the span and zero potentiometers are not moved from their calibrated positions.

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Instruction Manual

Section 4 Principle of Operation44

The following paragraphs describe the functional parts of the 846. Figure 4-1 shows the block diagram.

Figure 4-1. Functional Parts Block Diagram

4 to 20 MA

INPUT

ELECTRONIC CIRCUIT

MAGNETIC ACTUATOR

SOLID‐STATE

PILOT STAGE

PRESSURE SENSOR

D102005X012

BOOSTER STAGE

TO VALVE ACTUATOR

A6324‐1

3 TO 15 PSI

OUTPUT, TYPICAL

Electronic Circuit

During operation, the input current signal is received by the transducer's electronic circuit and compared to the output pressure from the booster stage. A solid‐state pressure sensor is part of the electronic circuit and monitors the booster stage output. The silicon‐based sensor uses strain gauge thin film technology.

The sensors pressure signal is fed to a simple internal control circuit. By using this technique, the transducer's performance is set by the sensor/circuit combination. Changes in output load (leaks), variations in supply pressure, or even component wear are sensed and corrected by the sensor/circuit combination. Electronic feedback allows crisp dynamic performance and readily compensates for output changes induced by vibration.

Note

Because the transducer is electronic in nature, it is not well‐modeled in the loop as a simple resistor in series with an inductor. It is better thought of as a 50‐ohm resistor in series with a 6.0 V voltage drop, with negligible inductance.

This is important when calculating the loop load. When the transducer is used in series with a microprocessor‐based transmitter, the noninductive nature of the transducer allows digital signals to successfully pass through undistorted.

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Magnetic Actuator

The electronic circuit controls the level of current flowing through the actuator coil, which is located in the pilot/actuator assembly. A change to the level of coil current is made by the electronic circuit when it senses a discrepancy between the pressure measured by the sensor and the pressure required by the input signal.

The actuator performs the task of converting electrical energy (current) to motion. It uses a coaxial moving magnet design optimized for efficient operation and is highly damped at its mechanical resonance. A silicone rubber diaphragm helps to protects its working magnetic gaps from contamination.

Pilot Stage

The pilot stage contains two opposed fixed nozzles: the supply nozzle and the receiver nozzle. It also contains the deflector, which is the moving element. See figures 4-2 and 4-3. The supply nozzle is connected to the supply air and provides a high‐velocity air stream. The receiver nozzle captures the air stream and converts it back to pressure. The receiver nozzle pressure is the output pressure of the pilot stage.

Figure 4-2. Deflector/Nozzle Pilot Stage Operation (Direct Action)

REGULATED AIR SUPPLY

A6645

HIGH OUTPUT PRESSURE

PRESSURE TO BOOSTER STAGE

LOW OUTPUT PRESSURE

DEFLECTED NOZZLE FLOW PATTERN

PRESSURE TO BOOSTER STAGE

To vary the pilot output pressure, the high‐velocity stream is diverted away from the receiver nozzle by the deflector, which is a cylindrical, aerodynamic body located between the two nozzles.

In response to a change in actuator coil current, the deflector is repositioned between the nozzles. There is a linear relationship between the coil current and the pilot stage output pressure. For direct action units, the power‐off, or fail‐safe, position of the top of the deflector is near the center of the stream and results in nearly zero pilot output pressure. As the coil is energized, the deflector is drawn out of the stream.

For reverse action units, the power‐off, or fail‐safe, position of the deflector is completely out of the stream. The result is maximum pilot output pressure. As the coil is energized, the deflector moves into the stream, resulting in a decreased pilot output pressure.

The deflector material is tungsten carbide, and the nozzles are 316 stainless steel. The nozzles have a large bore of

0.41 mm (0.016 inches), which provides good resistance to plugging.

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Figure 4-3. Detail of Deflector/Nozzle Pilot Stage

W6287

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Booster Stage

The receiver nozzle pressure controls the booster stage, which has a poppet valve design. An increase in receiver nozzle pressure positions the valving in the booster stage to produce an increase in the transducer output signal. A decrease in the receiver nozzle pressure positions the valving in the booster stage to allow exhaust to occur, decreasing the output signal.

The booster stage operates using a 3:1 pressure gain from the pilot stage. High flow rate capability is achieved by large flow area poppet design and internal porting having low flow resistance. The booster stage design provides very good stability in high vibration applications, and the poppet valve technology provides resistance to plugging.

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Section 5 Troubleshooting55

The modular design and unitized subassemblies of the 846 allows for quick and easy troubleshooting and repair. This section presents information on the diagnostic features and procedures for troubleshooting both models in service or in the shop.

Diagnostic Features

If a control loop does not perform properly and the cause of malfunction has not been determined, two features of the transducer can be used to determine if the transducer is at fault: the stroke port and Remote Pressure Reading.

Stroke Port

The stroke port provides a way to quickly increase the transducer output, giving a rough measure of the unit's functionality. A hole in the module cover vents the constant bleed from the pilot stage. When the hole is covered, pressure at the pilot stage receiver nozzle increases, which in turn increases the output. Output pressure will increase to within 2 psi of supply pressure for either direct or reverse action. If output pressure does not increase to this level, it may indicate that supply air is not reaching the pilot stage or that a pilot stage nozzle is plugged.

Note

If the stroke port diagnostic feature is not desired, the transducer is available with an optional cover that contains multiple stroke ports, as shown in figure 2-1. This prevents increasing the output by covering the stroke port.

Remote Pressure Reading (RPR)

Remote Pressure Reading (RPR) is an optional diagnostic feature that enables the user to determine the output pressure from any location along the signal wire path. For loop troubleshooting, this allows the user to confirm the functionality of the transducer from a remote location.

A frequency signal directly proportional to the output pressure is superimposed on the input signal loop. The frequency range of the RPR function is 0 to 10,000 Hz.

A jumper on the circuit board activates the Remote Pressure Reading function. The Maintenance section provides instruction on positioning the jumper. The jumper, shown in figure 6-4, has two positions: N for ON, or D for OFF. The RPR jumper is in the N (ON) position when the unit ships from the factory, unless otherwise specified.

Using a Frequency Counter to Read the RPR Signal

A frequency counter can be used for Remote Pressure Reading. The frequency counter displays the RPR output frequency that can be converted to output pressure using a simple mathematical line formula as shown below. Figure 5-1 shows the wiring connections.

Notes

The Remote Pressure Reading (RPR) frequency signal has an amplitude of 0.4 to 1.0 V peak‐to‐peak. If other noise (frequency) with a comparable or greater amplitude is present on the line, it may make the RPR frequency signal unreadable.

The following procedure is applicable for 846 transducers manufactured starting March 2015. Contact your Emerson Process

Management sales office for information on reading the RPR signal for products purchased prior to this date.

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Equations

(1) P = m(p) + b

P = pressure p = frequency

(2) m =

Procedure

- P

- p

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Example

= 3 psig

= 15 psig p2 = 9000 Hz

m = =

15 - 3 12

9000-6000 3000

= 6000 Hz

1) Find frequencies at zero and span pressure.

2) Solve for m, using equation (2).

3) Solve for b by inserting m, initial pressure, and initial frequency into equation (1).

4) Insert m and b into equation (1) to find conversion formula.

Figure 5-1. Wiring Connections for Frequency Counter

CONTROLLER

POWER SUPPLY

FREQUENCY COUNTER

3 = (6000) + b

3000

b = 3-24 b = -21

P = (p) - 21

3000

TEST PINS

POSITIVE

NEGATIVE

GROUND

B2466

In‐service Troubleshooting

A number of simple checks can be made on the transducer while the unit is in service. Figure 5-2 shows a troubleshooting flowchart.

1. Make sure that the module cover is tight. The cover should be hand‐tightened and then advanced 1/4 to 1/2 turn (24 to 27 NSm) (18 to 20 lbfSft).

2. Confirm the general functionality of the unit by using the diagnostic features described earlier in this section.

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Figure 5-2. Field Troubleshooting Flowchart

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TROUBLESHOOTING

FROM THE CONTROL ROOM

TROUBLESHOOTING

IN THE FIELD

NOTE: AFTER FINAL CORRECTIVE ACTION, CHECK LOOP OPERATION. IF NOT OK, RESTART TROUBLESHOOTING PROCEDURE. 1 REFER TO REPLACING THE MODULE FINAL ASSEMBLY IN SECTION 6.

C0789

3. Confirm that the filter‐regulator is not full of water or oil and that supply air is reaching the unit. The air supply pressure should be at least 0.2 bar (3 psi) greater than the maximum calibrated output pressure.

4. Confirm that there are no major leaks in the output signal line or from the output gauge port.

5. Confirm that there are no obstructions and the screens are clean in the stroke port or the exhaust port.

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WARNING

Personal injury or property damage could result from an uncontrolled process. Unscrewing the module cover removes power from the electronics and the output signal will be 0.0 psi. Before removing the module cover, ensure the process is properly controlled.

WARNING

Personal injury or property damage could result from fire or an explosion. In explosive atmospheres, remove power and shut off the air supply to the transducer before attempting to remove the terminal compartment cover or module cover. Failure to do so could result in an electrical spark or explosion.

6. If applicable, remove the cover lock and screw to allow access to the terminal compartment cover.

7. Remove the terminal compartment cover (see Warning above), and use a milliammeter, or a digital voltmeter to confirm that proper input current is supplied to the transducer.

8. Remove the terminal compartment cover (see Warning above), and short the loop across the positive (+) and the negative (-) terminals to check the output. The output should be nearly 0 psi. If the output is not 0 psi, replace the module final assembly.

9. Remove the terminal compartment cover (see Warning above), and, using a digital voltmeter, check the voltage between the transducer positive (+) and negative (-) terminals. The voltage should measure 6.0 to 8.2 V. A lower voltage can indicate a short in the input wires or defective controller. No voltage can indicate an open circuit in the control loop. A voltage of greater than 8.5 volts indicates a problem with the transducer, a faulty or corroded connection at the transducer, or an overcurrent condition. Replace the module final assembly. If the voltage is still not in the proper range (6.0 to 8.2 V), remove the terminal block and terminal block connection board. Apply power to the electrical feedthroughs. (Note the polarity of the feedthroughs, shown in figure 6-8.) Recheck the voltage. If the voltage is in the proper range, replace the terminal block and terminal block connection board. If the voltage is still not in the proper range, replace the housing.

10. Prepare to remove the module final assembly from the housing, or to remove the transducer from its mounting bracket. Refer to Module Final Assembly in the Maintenance section for instructions on removing the module final assembly from the module housing.

WARNING

Personal injury or property damage could result from an uncontrolled process. Unscrewing the module cover removes power from the electronics and the output signal will be 0.0 psi. Before removing the module cover, ensure the process is properly controlled.

With the module final assembly removed from the housing, the following checks can be made.

1. Review the position of the Remote Pressure Reading jumper (if so equipped) and range jumper to confirm that they are placed in the desired position. Refer to Electronic Circuit Board in the Maintenance section, and figure 6-4 for the location of these jumpers and instructions on placement.

2. Observe the position and condition of the three module O‐rings to confirm they make a tight seal.

3. Verify that the O‐ring is correctly positioned in the groove on the flat face of the module cover. Refer to figure 6-8 for an exploded view.

4. Inspect the porting on the module final assembly to determine if large amounts of contaminants have entered the transducer.

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Before making the following checks, disconnect both signal wires from the transducer, and ensure the module final assembly is removed from the housing.

1. Using an ohmmeter, check the electrical connections in the housing terminal compartment. The circuit should show an open between the positive (+) and negative (-) terminals. If not, replace the housing or terminal block and connection board.

2. Use a wire jumper to connect the two electrical feedthroughs located in the module compartment. The resistance between the positive (+) and negative (-) terminals in the terminal compartment should be 10 ohms. If not, check the electrical feedthroughs for short or open circuits. If a short or open circuit is found, replace the housing.

3. With the electrical feedthroughs jumpered as stated above, connect the ohmmeter to either the positive (+) or negative (-) terminal and the grounding lug. The circuit should show an open. If not, check for a short to the housing.

4. Remove the module from the module cover and inspect the pilot/actuator assembly for damage or clogging.

Some of the previous troubleshooting steps may be inconvenient to perform in the field. It may be best to make use of the modular design of the 846 and keep a spare, calibrated module final assembly available for exchange. If the module final assembly is to be transported to the shop for repair, first remove it from the module cover. Attach the spare module final assembly to the module cover. Refer to Module Final Assembly in the Maintenance section for complete instructions. The nonfunctioning module can then be returned to the shop for troubleshooting.

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Troubleshooting in the Shop

If the entire transducer is brought to the shop for troubleshooting, then the preceding sequence applies. If only the module final assembly has been brought to the shop, then use another 846 housing as a test fixture. Insert the module into the test fixture. Perform the previous steps (as they apply) of the In‐service Troubleshooting procedure.

To further aid troubleshooting, the module final assembly can be broken down into three subassemblies. The troubleshooting sequence consists of exchanging the subassemblies with known working ones to determine which is at fault. The three subassemblies are the pilot/actuator assembly, the electronic circuit board, and the module subassembly. The module subassembly consists of the module final assembly with both the pilot/actuator assembly and electronic circuit board removed.

1. Remove the pilot/actuator assembly. Refer to Pilot/Actuator Assembly in the Maintenance section for complete removal information.

CAUTION

Do not apply force to the deflector bar while cleaning the nozzles. Doing so could alter the alignment or disable the deflector bar mechanism.

CAUTION

Do not use chlorinated solvents for cleaning the pilot/actuator assembly. The chlorinated solvents will deteriorate the rubber diaphragm.

a. Inspect the nozzles and deflector. If they show a buildup of contaminants, clean the nozzles by gently inserting a

wire with a maximum diameter of 0.38 mm (0.015 inches). Clean the deflector, if necessary, by spraying with contact cleaner.

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b. Make sure the O‐rings are lightly lubricated with silicone grease and properly seated.

c. Reassemble and check operation.

d. If after cleaning the transducer does not function, replace the pilot/actuator assembly with a new one.

e. Reassemble and check operation.

2. Remove the electronic circuit board from the module final assembly. The Maintenance section describes how to remove the board.

a. Inspect the O‐rings around the sensor for damage and replace them if necessary.

b. Check the sensor port and areas around the sensor for foreign material, and clean if necessary.

c. Reassemble and check operation.

d. If the transducer does not function, replace the electronic circuit board with a new one. Refer to Electronic

Circuit Board in the Maintenance section for complete removal information.

e. Reassemble and check operation.

3. The module subassembly is aligned at the factory and should not be further disassembled. If the above steps fail to produce a working unit, the module subassembly is faulty and should be replaced.

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March 2015

Section 6 Maintenance66

This section describes the major components, assembly, and disassembly of 846 current‐to‐pressure transducers.

WARNING

To avoid personal injury or property damage from the sudden release of pressure or air:

D Always wear protective clothing, gloves, and eyewear when performing any maintenance operations.

D Disconnect any operating lines providing air pressure, electric power, or a control signal to the actuator. Be sure the

actuator cannot suddenly open or close the valve.

D Use bypass valves or completely shut off the process to isolate the valve from process pressure. Relieve process pressure

on both sides of the valve.

D Use lock‐out procedures to be sure that the above measures stay in effect while you work on the equipment.

D Check with your process or safety engineer for any additional measures that must be taken to protect against process

media.

WARNING

The presence of Emerson Process Management personnel and approval agency personnel may be required if you service (other than normal, routine maintenance, such as calibration) or replace components on an 846 transducer that carries a third‐party approval. When replacing components, use only components specified by the factory. Substitution with other components may void the third‐party approval and result in personal injury or property damage.

Use only the procedures, and component replacement techniques specifically referenced in this manual. Unauthorized procedures and improper techniques can cause poor quality repairs, impair the safety features of the device, and affect product performance and the output signal used to control a process.

Module Final Assembly

WARNING

Refer to the Maintenance WARNINGS at the beginning of this section.

The active mechanical and electrical components of the transducer are incorporated into a single, field‐replaceable module called the module final assembly, as shown in figure 6-1. Electrical connection between the terminal compartment and module final assembly is made by electrical feedthroughs that extend into the module compartment. The feedthroughs enter sockets on the electronic circuit board. The span and zero screws extend through the terminal compartment wall into the module compartment. Connection to the span and zero potentiometers on the electronic circuit board is made by hook and loop fasteners.

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The module final assembly has three separate radial ports. The upper port is for supply air, the middle port for the output signal, and the lower ports for exhaust. Three O‐rings separate the ports. The two lower O‐rings are the same size, and the upper O‐ring is slightly smaller. Table 6-1 shows O‐ring sizes.

The module final assembly is attached to the module cover, which allows insertion and removal, and can be separated from the module cover for further disassembly. A module cover O‐ring provides a seal between the module cover and module final assembly. Table 6-1 shows the O‐ring sizes. A slip ring is located around the module feet. It allows the module cover to turn easily when the module final assembly is being removed from the housing.

The module final assembly consists of three major subassemblies, as shown in figure 6-1. They are the electronic circuit board, pilot/actuator assembly, and module subassembly.

Table 6-1. O‐Ring Sizes

Description Qty. Size

Module O‐rings 1

2 Pilot/Actuator O‐rings 2 006

Circuit Board O‐rings 2

1 Module Cover O‐ring 1 238

Terminal Cover O‐ring 1 238

Filter‐Regulator O‐ring 1 114

043 042

016 005

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Figure 6-1. Fisher 846 Exploded View

ELECTRONIC CIRCUIT BOARD O‐RINGS

TERMINAL COVER

MODULE

O‐RINGS

MODULE HOUSING

V‐GROOVE ALIGNMENT MARK

ELECTRONIC CIRCUIT BOARD SCREWS

ELECTRONIC CIRCUIT BOARD

MODULE SUBASSEMBLY

PILOT/ACTUATOR ASSEMBLY

PILOT/ACTUATOR ASSEMBLY O‐RINGS

PILOT/ACTUATOR ASSEMBLY SCREWS

MODULE FINAL ASSEMBLY

V‐GROOVE

MODULE FEET

C0790

KEY SLOT

STROKE PORT SCREEN

RETAINING CLIP (2)

O‐RING CLIP

COVER SLOT (2)

SLIP RING

O‐RING

ALIGNMENT KEY

MODULE COVER

NOTE:

1 THREE O‐RINGS ARE REQUIRED FOR THE MODULE SUBASSEMBLY. FOR ATEX / IECEx—FLAMEPROOF APPROVED UNITS THE TWO UPPER O‐RINGS ARE SILICONE AND THE LOWER O‐RING IS NITRILE. ALL OTHER UNITS HAVE THREE NITRILE O‐RINGS.

MODULE COVER INDICATING BOSS

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Removing the Module Final Assembly

The module final assembly is attached to the module cover. Removing the module cover automatically removes the module final assembly from the housing. When the module cover is unscrewed, the electrical feedthroughs and span and zero adjustments automatically disengage. The internal air ports are also disengaged. The air supply to the transducer should be turned off to prevent uncontrolled air loss through the housing.

WARNING

Personal injury or property damage could result from an uncontrolled process. Unscrewing the module cover removes power from the electronics and the output signal will be 0.0 psi.

Refer to the WARNING at the beginning of this section before removing the module cover to ensure the process is properly controlled.

WARNING

Use the following steps to remove the module final assembly from the housing and module cover:

1. Shut off the air supply. If applicable, remove the cover lock and screw to allow access to the terminal compartment cover. Unscrew the module cover. When the module cover threads clear the housing, slowly pull on the cover, and the module final assembly will gradually come out of the housing.

Note

The module and the housing are designed for minimal clearance; therefore, patience may be required while pulling on the cover. Time must be allowed for release of the vacuum effect between the housing and module. If the module becomes tilted and cannot be removed, reinsert it completely into the housing and fully engage the module cover threads. Then proceed again with removal, ensuring that you pull slowly in a straight line.

Support both the module cover and the module final assembly as it comes out of the housing. This is to prevent dropping them, should they become detached accidentally.

WARNING

Do not grip the module cover threads. The threads are sharp and may cause minor injury. Wear gloves when removing the module cover.

2. Prepare to remove the module final assembly from the module cover. Align the module feet with the two interior cover slots. To accomplish this, identify the indicating boss on the module cover, shown in figure 6-2.

Grasp the module cover with one hand and the module final assembly with the other hand. Rotate the module final assembly so that the module alignment key is directly above the indicating boss on the module cover. Figure 6-2 shows the module alignment key and the indicating boss. The module feet are now aligned with the cover slots.

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March 2015

3. Remove the module final assembly from the module cover. To accomplish this, hold the cover steady, and push the module final assembly in the direction of the module cover indicating boss. At the same time, lift the opposite foot of the module final assembly out of the cover slot, as shown in figure 6-3.

Figure 6-2. Alignment Key Above Module Cover Indicating Boss

MODULE ALIGNMENT KEY

INDICATING BOSS

A6649

Figure 6-3. Removing the Module Final Assembly from the Module Cover

A6650

Replacing the Module Final Assembly

Use the following procedure to attach the module cover and replace the module final assembly:

1. Ensure that the electronic circuit board and the pilot actuator assembly provide the desired action (direct or reverse). See the Electronic Circuit Board and Pilot/actuator Assembly Action descriptions later in this section.

2. Ensure that the slip ring is in place around the feet of the module final assembly. The module cover O‐ring should be lightly lubricated with silicone grease and placed in the O‐ring gland. The stroke port screen should be clean and in place.

Note

The module cover O‐ring must be in the O‐ring gland, not down on the threads of the cover. This will ensure proper sealing of the pilot pressure area.

3. Position the retaining clips in the module cover so they are ready to accept the feet of the module final assembly. Ensure the leaves on the retaining clips are facing up. Figure 6-1 shows the correct orientation.

4. Insert one of the module feet into a cover slot, and push on the module final assembly to compress the retaining clip. Insert the opposite foot into the opposite cover slot, and rotate the module 90 degrees in the module cover to secure it in place.

5. Ensure that the three module O‐rings are in the O‐ring glands and are lightly lubricated with silicone grease. Inspect the O‐rings to ensure that they are not twisted or stretched.

6. Apply lubricant to module cover threads for ease of assembly.

7. Prepare to insert the module into the housing. Align the V‐groove located on the module final assembly with the indicating mark located on the nameplate. This positions the alignment key with the key slot. Figure 6-1 shows the location of the V‐groove and the indicating mark.

8. Insert the module, engage the module cover threads, and screw on the module cover. The module final assembly will automatically engage the electrical feedthroughs and span and zero screws.

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9. Hand tighten the module cover as much as possible. Use a wrench or long screwdriver shaft to tighten the module cover an additional 1/4 to 1/2 turn [24 to 27 NSm (18 to 20 lbfSft)]. For units with ATEX/IECEx Flameproof approvals, make sure the cover lock and screw are securely re‐installed. The screw accepts a 3 mm hex drive.

Note

When the module cover is tightened, connection is made with the electrical feedthroughs and span and zero screws, and the module final assembly O‐rings become seated. Failure to fully tighten the module cover may prevent the transducer from operating properly.

Electronic Circuit Board

WARNING

Refer to the Maintenance WARNINGS at the beginning of this section.

The electronic circuit board is located on top of the module final assembly, as shown in figure 6-1. Beneath the circuit board and permanently attached to it is the pressure sensor. Two jumpers on the circuit board control various functions of the transducer. Figure 6-4 shows the location of these jumpers.

Figure 6-4. Circuit Board Jumper Positions

NOTE:

1 RPR JUMPER ONLY ON UNITS WITH REMOTE PRESSURE READING (RPR) OPTION

A6652

RPR ON

LOW RANGE

RPR OFF

HIGH RANGE

Optional Remote Pressure Reading (RPR) Jumper

Remote Pressure Reading (RPR) is an optional diagnostic feature that enables the operator to determine the transducer output signal from any location along the signal wire path. The transducer generates a frequency signal

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that can be received by a frequency counter. Operation of the RPR feature is jumper‐selectable, in units so equipped. The RPR feature operates when the jumper is located in the N position on the circuit board. With the jumper in the D position, the RPR feature does not operate. When the RPR feature is included, the transducer is shipped with the RPR jumper in the N position, unless otherwise specified. For more information about the RPR feature, refer to Remote Pressure Reading (RPR) in the Troubleshooting section.

Note

When operating 846 transducers in series, only one unit may be configured for Remote Pressure Reading. Activating the RPR feature in two units will result in an unusable RPR signal.

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Range Jumper

The range jumper is positioned according to the calibration specified. All full span calibrations and some split range calibrations can be accomplished with the range jumper in the High Range position. Some split range calibrations require the jumper to be in the Low Range position. For more information about the range jumper, refer to Standard Performance: Split Range Input, Direct Action in the Principle of Operation section.

Action

For direct action units, output changes directly with a corresponding change in input. For example, as the input increases from 4 to 20 mA the output increases from 0.2 to 1.0 bar (3 to 15 psi). Direct action circuit boards are green in color.

For reverse action units, output changes inversely with a change in input. For example, as the input increases from 4 to 20 mA the output decreases from 1.0 to 0.2 bar (15 to 3 psi). Reverse action circuit boards are red in color.

Upon loss of input current, or if input current decreases below 3.3 $0.3 mA, the output of the direct action unit decreases to less than 0.1 bar (1 psi). In the same situation, the output of the reverse action unit increases to near supply pressure.

Removing the Electronic Circuit Board

The electronic circuit board is connected to the module final assembly by five mounting screws. The circuit board must be removed to inspect the pressure sensor located beneath it. To remove the circuit board, remove the five mounting screws and pull upward on the plastic board standoff (black=multirange; white=standard).

CAUTION

Standard electronic assembly handling procedures apply. Do not attempt to remove the circuit board by pulling on the components. Doing so could weaken the connections and disable the electronics.

Be careful when handling the pressure sensor located beneath the circuit board. The pressure sensor lead frame is bent to allow the pressure sensor to fit properly in the sensor cavity of the module final assembly, and to maintain flush contact with the pressure sensor manifold.

Three O‐rings accompany the pressure sensor. Two O‐rings of the same size are located on each side of the pressure sensor. A third, smaller O‐ring is positioned in the beveled O‐ring gland of the module sub‐assembly. Table 6-1 shows

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the O‐ring sizes. The pressure sensor may be gently bent away from the pressure sensor manifold to access the sensor O‐ring and confirm that the pressure ports are clear.

Replacing the Electronic Circuit Board

1. Verify that the circuit board is green for assembly into a direct action unit, or red for assembly into a reverse action unit.

2. Ensure that the three O‐rings are in the proper position. The small O‐ring is positioned in the beveled O‐ring gland of the module subassembly. The two sensor O‐rings are each positioned on the shoulders of the sensor. They should be lightly lubricated with silicone grease.

3. Ensure that the pressure sensor is correctly positioned against the manifold. The pressure sensor should be centered and in contact with the manifold, as shown in figure 6-5.

4. Position the circuit board on the module subassembly. Ensure that the circuit board mounting holes match those on the module subassembly. Place the three long screws in the mounting holes adjacent to the pressure sensor.

5. Place the two short screws in the remaining mounting holes. Tighten the three long screws first, then tighten the remaining two screws.

Figure 6-5. Positioning the Pressure Sensor

ELECTRONIC

CORRECT POSITION

CIRCUIT BOARD

MANIFOLD

INCORRECT POSITION

A6653

SOLID STATE PRESSURE SENSOR

MANIFOLD

ELECTRONIC CIRCUIT BOARD

Pilot/Actuator Assembly

WARNING

Refer to the Maintenance WARNINGS at the beginning of this section.

The pilot/actuator assembly is located at the bottom of the module final assembly, as shown in figure 6‐1. It is a unitized assembly consisting of the coil, magnet, and spring of the actuator, and the deflector and nozzles of the pilot stage. Two O‐rings are part of the pilot/actuator assembly. Table 6-1 shows the O‐ring sizes. They are located in the beveled O‐ring glands of the module subassembly, adjacent to the nozzles. The pilot/actuator assembly is held in place by four mounting screws.

Action

A blue rubber diaphragm under the deflector bar and nozzle area identifies the direct action pilot/actuator assembly. A red diaphragm under the nozzle area identifies the reverse action pilot/actuator assembly. Figure 6-6 shows the bottom view of the pilot/actuator assembly.

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Figure 6-6. Pilot/Actuator Assembly (Bottom View)

ALIGNMENT KEY

RUBBER DIAPHRAGM

MOUNTING SCREWS

A6654

Removing the Pilot/Actuator Assembly

To remove the pilot/actuator assembly, disengage the four mounting screws, and gently pull the assembly out of the module subassembly. To aid removal, the pilot/actuator framework may be gently gripped with a pair of pliers.

CAUTION

Do not attempt to remove the pilot/actuator assembly by gripping or pulling on the deflector or nozzles. Doing so could alter the alignment or disable the deflector/nozzle mechanism.

Inspect the assembly for a buildup of foreign material. The nozzle passageways should be clear, and the deflector should be clean. The deflector can be cleaned by spraying it with contact cleaner. Clean the nozzles by gently inserting a wire with a maximum diameter of 0.38 mm (0.015 inches).

D Insert the wire into each nozzle separately from the outside as shown in figure 6-7.

D Do not try to put the wire through both nozzles simultaneously.

D Do not push the wire on the deflector bar.

CAUTION

Do not apply force to the deflector bar while cleaning the nozzles. Doing so could alter the alignment or disable the deflector mechanism.

CAUTION

Do not use chlorinated solvents for cleaning the pilot/actuator assembly. The chlorinated solvents will deteriorate the rubber diaphragm

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Figure 6-7. Cleaning the Nozzles

WIRE

PLASTIC HOUSING

A6655‐1

WIRE

DEFLECTOR BAR

Replacing the Pilot/Actuator Assembly

1. Verify that the rubber diaphragm under the nozzle area is blue for pilot/actuators inserted into a direct action unit, or red for pilot/actuators inserted into a reverse action unit.

2. Inspect the pilot/actuator assembly cavity in the module final assembly to ensure that it is clean.

3. Lightly lubricate the two O‐rings with silicone grease, and place them in the beveled O‐ring glands. O‐rings between the pilot/actuator assembly and the module should be installed justified to the lower portion of the O‐ring gland. When properly positioned, the air passageway should be visible through the O‐ring inside diameter.

4. Prepare to insert the assembly by aligning the key on the pilot/actuator assembly with the key slot in the module subassembly.

5. Insert the assembly into the module subassembly, and engage the four mounting screws.

Module Subassembly

WARNING

Refer to the Maintenance WARNING at the beginning of this section.

The module subassembly, shown in figure 6-1, consists of the module final assembly with both the electronic circuit board and pilot/actuator assembly removed. The module subassembly contains the porting and valving for the booster stage.

Note

The module subassembly is aligned at the factory and should not be further disassembled. Disassembling the module subassembly may result in performance outside specifications.

Terminal Compartment

WARNING

Refer to the Maintenance WARNING at the beginning of this section.

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The terminal compartment contains the terminal block, terminal block connection board, span and zero screws, electrical feedthroughs, and internal grounding lug, as shown in figure 6-8. The terminal block connection board is attached to the terminal block and to the electrical feedthroughs.

Figure 6-8. Terminal Compartment Exploded View

TEST PINS

ZERO AND SPAN SCREWS

GROUNDING LUG

TERMINAL BLOCK CONNECTION BOARD

TERMINAL BLOCK

ELECTRICAL FEEDTHROUGHS

A6656

Separate test points are provided that have a 10‐ohm resistor in series with the signal negative (-) terminal. The test points allow the input current to be determined with a voltmeter without disconnecting a signal lead. A 4 to 20 mA span produces a 40 to 200 mV DC voltage drop across the 10‐ohm resistor. The test points can accommodate different connections, including alligator clips and E-Z hooks.

The terminal block and terminal block connection board can be removed by disengaging the two terminal block mounting screws. Lubricate the terminal compartment cover threads with anti‐seizing paste or a low temperature lubricant. See table 6-1 for the size of the terminal compartment cover O‐ring.

Exhaust and Stroke Port Screens

WARNING

Refer to the Maintenance WARNING at the beginning of this section.

Two identical screens, the exhaust port screen and the stroke port screen, allow air to vent to the outside environment. The exhaust port screen is located behind the nameplate. Removing the two nameplate screws and rotating the nameplate to the side allows access to the exhaust port screen. Figure 7-3 shows an exploded parts view.

The stroke port screen is located at the center of the module cover. Removing the module final assembly from the housing and then from the module cover allows access to the stroke port screen. Removing the Module Final Assembly earlier in this section describes this procedure. Figure 7-3 shows an exploded parts view.

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Section 7 Parts 77

Whenever corresponding with your Emerson Process Management sales office about this equipment, always mention the transducer serial number.

WARNING

Use only genuine Fisher replacement parts. Components that are not supplied by Emerson Process Management should not, under any circumstances, be used in any Fisher instrument. Use of components not supplied by Emerson Process Management may void your warranty, might adversely affect the performance of the instrument, and could cause personal injury and property damage.

Parts Kit

Description Part Number

Repair Kit [Kit includes O-rings and slip ring] R846X000012

Parts List

See table 7-1.

Note

Contact your Emerson Process Management sales office numbers.

Table 7-1. Parts List

Key No. Description Spares Category

Module, standard - Final Assembly

Standard Performance

Direct Action 4-20 mA Reverse Action 4-20 mA

Multirange Performance

Direct Action 4-20 mA

12*

15*

Reverse Action 4-20 mA

Module, ATEX/IECEx Ex d and Dust - Final Assembly

Standard Performance

Direct Action 4-20 mA Reverse Action 4-20 mA

Multirange Performance

Direct Action 4-20 mA Reverse Action 4-20 mA

Module Subassembly

Standard Performance (Direct or Reverse Action) ATEX/IECEx Ex d and Dust (Direct or Reverse Action)

Pilot/Actuator Assembly

Direct Action Reverse Action

Circuit Board Assembly

Standard Performance

Direct Action Reverse Action

(3,4)

Housing

Standard ATEX/IECEx Ex d and Dust

Module Cover

Single Stroke Port Multiple Ports Threaded Stroke Port

(1,2)

(2)

(1)

for part

(6)

B B

C C

C C C

*Recommended spare parts

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Table 7‐1. Parts List (continued)

Key No. Description Spares Category

1* Terminal Compartment Cover C

5* Terminal Block Kit

16* Screens (12/pkg) B

O‐Rings

10*

Module (5/kit) Module (5/kit, ATEX/IECEx Ex d and Dust)

11*

2*, 21*, & 23*

Pilot/Actuator (5/kit) Circuit Board (5/kit) Cover (12 O‐rings, 12 slip rings) Filter‐Regulator (10/kit)

Screws

13*

14*

Pilot/Actuator (3/kit) Circuit Board (3/kit) Nameplate (3/kit)

18* Retaining Clips (3/kit)

22* Module Cap (5/pkg)

Filter‐Regulator Direct Mounting Kit

SST Bolts B

Filter‐Regulator with Direct Mounting Kit

SST Bolts C

Universal Mounting Bracket

Epoxy Painted Carbon Steel, Carbon Steel Nuts/Bolts Epoxy Painted Carbon steel, SST Nuts/Bolts 316 SST, SST Nuts/Bolts for use with SST Housing 316 SST, SST Nuts/Bolts for use with Aluminum Housing

Supply Gauge (see figure 7-1)

0‐60 psi/0‐400 kPa/0‐4 bar SST 0‐60 psi/0‐400 kPa/0‐4 bar

Output Gauge (see figure 7-2)

0‐30 psi/0‐200 kPa/0‐2 bar B 0‐60 psi/0‐400 kPa/0‐4 bar B SST 0‐60 psi/0‐400 kPa/0‐4 bar B

Tire Valve Adapter Assembly

1. For units with approvals other than ATEX/IECEx Ex d, use standard module.

2. Includes O‐rings.

3. Includes housing, span and zero screws, electrical feedthroughs, and grounding lug.

4. For units with approvals other than ATEX/IECEx Ex d, use standard housing.

5. Includes terminal block, connection board, and screws.

6. Spares Categories

Category A - Recommend 1 spare part per 25 transducers Category B - Recommend 1 spare part per 50 transducers Category C - None normally required.

7. #/kit indicates number of transducers that may be serviced.

8. Contains O‐rings for both housing styles.

9. Filter‐Regulator Direct Mounting Kit includes O‐ring.

10. Extra O‐ring and spacer included for both housing styles.

(5)

(7)

(7,8)

(7)

(9,10)

(6)

B B B B B B

C C C

C C C C

B B

Figure 7-1. Supply Gauge

*Recommended spare parts

14 sq (0.55)

1/4 NPT

(INCH)

Figure 7-2. Output Gauge

1/4 NPT

14 sq (0.55)

(INCH)

846 Transducer

March 2015

Figure 7-3. Exploded Parts Drawing (also see table 7-2)

B2467

Instruction Manual

D102005X012

NOTE:

1 THREE O‐RINGS ARE REQUIRED FOR THE MODULE SUBASSEMBLY. FOR ATEX/IECEx—FLAMEPROOF APPROVED UNITS THE TWO UPPER O‐RINGS ARE SILICONE AND THE LOWER O‐RING IS NITRILE. ALL OTHER UNITS HAVE THREE NITRILE O‐RINGS.

Table 7-2. Key Number Quick Reference

Key No. Description

1 Terminal Compartment Cover

2 Terminal Compartment Cover O‐ring

3 Housing

5 Terminal Block Kit

6 Electronic Circuit Board Screws

7 Electronic Circuit Board O‐rings

8 Electronic Circuit Board Assembly

9 Module Subassembly

10 Module O‐rings

11 Pilot/Actuator Assembly O‐rings

12 Pilot/Actuator Assembly

13 Pilot Actuator Assembly Screws

14 Nameplate Screws

15 Module Cover

16 Exhaust/Stroke Port Screen

18 Retaining Clip

21 Slip Ring

23 Module Cover O‐ring

Instruction Manual

D102005X012

Figure 7-3. Exploded Parts Drawing (also see table 7-2) (continued)

846 Transducer

March 2015

B2468

846 Transducer

March 2015

Instruction Manual

D102005X012

Section 8 Installation Drawings8

This section includes installation drawings required for wiring of intrinsically safe installations. If you have any questions, contact your Emerson Process Management sales office

Figure 8-1. CSA Installation Drawing GE59146

GE59146

Instruction Manual

D102005X012

Figure 8-2. FM Installation Drawing GE59147

846 Transducer

March 2015

GE59147

846 Transducer

March 2015

Instruction Manual

D102005X012

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Fisher is a mark owned by one of the companies in the Emerson Process Management business unit of Emerson Electric Co. Emerson Process Management, Emerson, and the Emerson logo are trademarks and service marks of Emerson Electric Co. All other marks are the property of their respective owners.

The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy, they are not to be construed as warranties or guarantees, express or implied, regarding the products or services described herein or their use or applicability. All sales are governed by our terms and conditions, which are available upon request. We reserve the right to modify or improve the designs or specifications of such products at any time without notice.

Emerson Process Management

Marshalltown, Iowa 50158 USA Sorocaba, 18087 Brazil Chatham, Kent ME4 4QZ UK Dubai, United Arab Emirates Singapore 128461 Singapore

www.Fisher.com

Emerson Fisher 846 Instruction Manual

Specifications and Main Features

Frequently Asked Questions

User Manual