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Reference Manual
00809-0100-4860, Rev BC
Section 5: Troubleshooting
January 2013
Troubleshooting
5.3.2 Electronics test points
As shown in Figure 5-1, there are several test points located on the electronics.
LOW LOOP VOLTAGE The voltage at the transmitter terminals has dropped to a level that is causing the
internal voltage supplies to drop, reducing the capability of the transmitter to
accurately measure a flow signal. Check the terminal voltage and either increase the
power supply voltage or reduce loop resistance.
INTERNAL COMM FAULT After several attempts, the microprocessor failed in communication with the
Sigma-Delta ASIC. A power cycle may resolve the problem. Also, check the
inter-board connector. If the problem persists, replace the transmitter electronics.
INTERNAL SIGNAL FAULT The flow data encoded on a pulse signal from the Sigma-Delta ASIC to VDSP has been
lost. A power cycle may resolve the problem. Also check the inter-board connector. If
the problem persists, replace the transmitter electronics.
TEMPERATURE ELECTRONICS
FAILURE
The electronics circuitry that supports the measurement of the Process Temperature
has failed. The transmitter can still be used in a non-Process Temperature mode.
PROCESS TEMP OUT OF RANGE The Process Temperature is beyond the defined sensor limits of -50 °C to 427 °C.
PROCESS TEMP ABOVE SAT STEAM
LIMITS
The Process Temperature is above the high limit for Saturated Steam density
calculations. This status only occurs when the Process Fluid is Temperature
Compensated Saturated Steam. The density calculation will continue using a Process
Temperature of 320 °C.
PROCESS TEMP BELOW SAT STEAM
LIMITS
The Process Temperature is below the low limit for Saturated Steam density
calculations. This status only occurs when the Process Fluid is Temperature
Compensated Saturated Steam. The density calculation will continue using a Process
Temperature of 80 °C.
FIXED PROCESS TEMPERATURE IS
ACTIVE
Due to a problem detected with the thermocouple, a configured fixed Process
Temperature is being substituted for the measured Process Temperature. This fixed
Process Temperature is also being used in saturated steam density calculations.
INVALID MATH COEFF The area of nonvolatile memory used to store the curve fit coefficients for the
coprocessor calculations does not contain valid data. This data can only be loaded at
the factory. Replace the transmitter electronics.
CJ TEMP ABOVE SENSOR LIMITS The temperature reported from the Cold Junction temperature sensor is above CJ
sensor limits.
CJ TEMP BELOW SENSOR LIMITS The temperature reported from the Cold Junction temperature sensor is below CJ
sensor limits.
Figure 5-1. Electronics Test Points
GROUND
TP1
Test Freq IN