Greyline Instruments TTFM 1.0, User Manual

Page: 27 / 53

Page 27
TTFM 1.0 Transit Time Flow Meter
Possible Causes:
Corrective Action:
NO ECHO INDICATION Icon: No Echo
Sensor Connections

Check sensor connections at TTFM and at
sensor junction box.

Note: Refer to Sensor Cable Resistance Test to
test final connections.
Sensors not mounted to Pipe or mounted improperly

Apply coupling compound and mount sensors
to pipe with proper sensor spacing.
Empty pipe or partially filled

Pipe must be fluid filled and acoustically
transparent in order to obtain echoes.
Coupling compound washed out, or sensor loose on
pipe.

Remount sensor

Use Dow Corning Silicone #4
METER READING HIGHER THAN EXPECTED?
Calibration Error

Review calibration menu. Pipe dimensions and
fluid selection/fluid velocity.
Higher flow rate than expected

Investigate pump/valves. Compare velocity
with alternate instrument.
Erratic measurement (set damping to 0% to check) due
to electrical noise or poor signal quality.

Ensure all Flowmeter wiring is in METAL
conduit and sensor shield is properly grounded.

Ensure correct power input Ground connection
(<1 ohm resistance).

Ensure 4-20mA Shield connected to Instrument
Ground stud.

Try adjusting sensor spacing (+/- 10%) and
contact Greyline for further assistance.
Pipe not Full

Verify pipe is full by mounting sensors at top
of pipe and check echo icon.
No echo if pipe is not full.
High viscosity fluid

Laminar flow profile due to high viscosity fluid
requires an adjustment to Cal Const.