Fisher 444 Alphaline REPAIR

4-3

Maintenance and Troubleshooting

REPAIR

In case of a failure, particularly one in which the transmitter’s output goes to

one extreme and stays there, the first step is to determine whether the fault lies

with the sensor(s) or the transmitter. Although only a careful calibration can

determine sensor shifts, catastrophic failures (such as an open or shorted sensor

element) can be checked with an ohmmeter at the time the transmitter is

disconnected from the sensor(s).

NOTE

The Resistance vs. Temperature and Millivolt vs. Temperature tables for the

standard Model 444 sensor input types are presented in Table B-1 in Appendix

B Temperature Sensor Reference Information.

RTD Test: A platinum RTD with an ice-point (°C) resistance of 100 ohms should

read approximately as shown in Table B-1 at other temperatures. The resistance

between the two leads on the same side of the sensing element should be low, a

few ohms at most. Resistance between any of the RTD leads and the sensor

sheath should be high

(1 megohm or greater).

Thermocouple Test: Thermocouple resistance should be low (10 ohms or less

for short runs of heavy wire). For longer runs of extension wire, resistance will

be roughly ten times the resistance of copper wire of the same diameter. If the

sensor and receiving equipment are functioning properly, the transmitter will

probably require repair.

The transmitter is designed for easy replacement of its plug-in, modular circuit

boards. A malfunction can be most easily isolated by substituting boards one at a

time until the unit functions properly.

It is recommended that customers return defective circuit boards to Rosemount

Inc. for repair (see “RETURN OF MATERIALS” on page 4-6). This ensures that

replacement parts meet the design criteria for the board and that the

malfunctioning board is completely checked and repaired.

Rosemount Inc. offers a circuit board repair/replacement program through its

many service centers. Please contact your Rosemount field sales office for price

and delivery information.

Exposure to hazardous substances can cause death or

serious injury.If a hazardous substance is identified, a

Material Safety Data Sheet (MSDS), required by law to be

availableto people exposed to specific hazardous

substances, must be included with the returned materials.

Contents

Main Page Product Manual 7:00 a.m. to 7:00 p.m. CST) 24 hours a day IncludesCanada) NOTICE 1 Model 444 Alphaline Temperature Transmitters Page Table of Contents SECTION 1 Introduction SECTION 2 SECTION 3 Calibration Page 1Introduction OVERVIEW Page 2Installation OVERVIEW GENERAL MECHANICAL Mounting Stability Access Requirements 2-3 FIGURE2-1. Recommended Process Mounting. FIGURE2-2. Recommended Process Mountingwith Drain Seal. ELECTRICAL Power Supply Field Wiring 2-5 FIGURE 2-4. Field Wiring for the Standard Model 444 Transmitters. { FIGURE 2-5. Field Wiring for Low-Power Model 444 Transmitters (444LL and LM). Sensor Connections 2-6 FIGURE 2-7. Characteristicsof Thermocouple and RTD Input Wires. FIGURE 2-6.Sensor Wiring Diagrams. Grounding Multi-Channel Installations Surges/Transients ENVIRONMENTAL Temp era tur e Environment 2-9 FIGURE 2-9. Model444 Transmitter Housing TemperatureRise. FIGURE 2-10.Sensor AssemblyDimensional Drawings. Moist or Corrosive Environments HazardousLocation Intrinsically Safe PROCEDURE Mechanical Electrical Page 2-13 FIGURE 2-11.Model 444 with Optional Mounting Bracket. FIGURE 2-12.Model 444 Dimensional Drawings PIPESTAND MOUNTING PANEL OR SURFACE MOUNTING Page 3Calibration OVERVIEW SAFETY MESSAGES RTD TRANSMITTER Page 3-4 THERMOCOUPLE TRANSMITTER Using a Compensated Thermocouple Simulator + 3-6 U s i n ga nI c e B a t h LOW-POWER TRANSMITTER Page Page 4Maintenance and Troubleshooting OVERVIEW HARDWARE DIAGNOSTICS TROUBLESHOOTING 4-2 TABLE4-1. Transmitter TroubleshootingSymptoms andCorrectiveActions. Symptom PotentialSource CorrectiveAction REPAIR Disassembly Procedure Reassembly Procedure Interchangeability of Parts Burnout Protection Adjustments REPAIR AND WARRANTY SERVICE RETURN OF MATERIALS 5Specifications and Reference Data FUNCTIONAL Page PERFORMANCE PHYSICAL Page Page LCD METER (OPTIONS D AND E) Functional Specifications Performance Specifications Physical Specification Page 5-9 TABLE5-3. 444 Model Structure. TypicalModel Number: 0444 RL3 U 1 A 2 E5 Q4 Model Product Description Code Input Type(1) 5-10 TABLE5-4. 444RL Fast Turn-on Model Structure. 5-11 TABLE5-5. 444LL, LM Model Structure. TABLE5-6. Meter Kits. Model ProductDescription Code Input Type j 5-13 TABLE5-8. Parts List forModel W444 Transmitter (CESI/CENELEC Approval). j 5-14 TABLE5-9. Parts List forModel T444 Transmitter (BASEEFAApproval). 5-15 TABLE5-10. Parts List for Model 444 RL Fast Turn On Transmitter(RTD Input). TABLE5-11. Parts List for Model 444 LL, 444 LM Low PowerTransmitter (RTD Input). j 5-16 TABLE5-12. Parts List for Model 444 Increased Accuracy or Special Range Transmitters. Code D Not used on transmitters,but recommended for repair activities. Page Page 6Options MOUNTING BRACKET LCD / ANALOG METER LCD METER Configuration Page LCD Meter Assembly LCD Meter Page ANALOG METER } Analog Meter Page Page Page Page Page Page Appendix B-1 BTemperature Sensor Reference Information TABLEB-1. Resistance VersusTemperature Curve Ro=100.00,a=0.00385 Reference Standard IEC 751. Page I-1 Index A B C D S T U V W Page Page Rosemount Inc. http://www.rosemount.com Fisher-Rosemount Limited Fisher-Rosemount 00809-0100-4263z 00809-0100-4263, Rev. AA