Rosemount Model 444 Alphaline Temperature Transmitters
4-2

TABLE4-1. Transmitter

TroubleshootingSymptoms

andCorrectiveActions.

Symptom PotentialSource CorrectiveAction

HighOutput Sensor Checkfor a sensor or thermocouple open circuit. (RL, MV,T-Series with upscale burnout protectiononly)
LoopWiring Checkfor dirty or defective terminals, interconnectingpins, or receptacles.
ElectronicsAssembly Checkfor dirty or defective interconnecting pins.
ErraticOutput Loop Wiring Checkfor adequatevoltage to the transmitter.
Checkfor intermittent shorts, open circuits, and multiple grounds.
Checkfor dirty or defective terminals or interconnection pins.
ElectronicsAssembly Checkfor dirty or defective interconnecting pins.
LowOutput or
No Output Sensor Check RTD leads to ensure that theyare not shorting together or to ground. (RL only)
Checkfor correct RTD lead connection. (RL only)
Checkfor open RTD lead on double-lead side. (RL only)
LoopWiring Checkfor adequate voltage to the transmitter.(RL only)
Checkfor intermittent shorts, open circuits, and multiple grounds. (MV,T series only)
Checkfor proper polarity at the signal terminal. (MV,T series only)
Checkfor dirty or defective terminals or interconnection pins.
Excessive
Current
(over30 mA)
LoopWiring Checkfor short between current signal leads.
Checkto ensure that current signal leads ARE NOT connected to sensor terminals.
Checkthat sensor leads ARE NOT grounded when positive side ofpower supply is grounded (RL,
RL___B0912,LL, and LM)
ElectronicsAssembly Checkfor defective components in amplifier or current control section.
Excessive
Output Shift
withAmbient
Temperature
Sensor Checkfor incorrect thermocouple type or Incorrectthermocouple polarity connection (T series only)
ElectronicsAssembly Checkto ensure that the burnout -protection jumpers positioned correctly (MV,T series only).
Checkfor defective components in voltage regulatoror dc-to-ac converter section (MV, T series only).
Checkfor defective components in amplifier or current controlsection (all models).
Mayrequire replacement electronics assembly.
UnitCannot be
Trimmedto
Desired Base
Temperature
Transmitter Checkto ensure that unit is capable of desired range.
ElectronicsAssembly Checkto ensure that the range board jumper is in the correct position.
Checkto ensure that the burnout -protection jumpers positioned correctly.(MV, T series only).
Checkfor defective zero pot.
UnitCannot be
Trimmedto
DesiredSpan.
Transmitter Checkto ensure that unit is capable of desired range.
LoopWiring Checkfor adequate voltage to the transmitter.
ElectronicsAssembly Checkfor defective components in amplifier or current control section.
Checkfor defective components in voltage regulatorsection.
Checkfor defective span pot.