Suggested Proof Test; Safety Inspection; Float Inspection - K-TEK AccuTrak AT100 Installation & Operation Manual

6.0 SAFETY, MAINTENANCE, AND TROUBLESHOOTING

6.3 Suggested Proof Test

The suggested proof test consists of minimum and maximum current capability test followed by a two-point
calibration of the transmitter, see the suggested proof test Table. This text will detect > 99% of possible DU failures
in the device.
Step Action
1. Bypass the safety function and take appropriate action to avoid a false trip.
2. Use HART communications to retrieve any diagnostics and take appropriate action.
3. Send a HART command to the transmitter to go to the high alarm current output and verify that the analog
current reaches that value
4. Send a HART command to the transmitter to go to the low alarm current output and verify that the analog
current reaches that value
5. Perform a two-point calibration
6. Remove the bypass and otherwise restore normal operation.
Notes:
1. This tests for compliance voltage problems such as a low loop power supply voltage or increased wiring resistance. This also tests
for other possible features.
2. This tests for possible quiescent current related failures.
3. If the two-point calibration is performed with electrical instrumentation, this proof test will not detect any failures of the sensor.
6.4 Safety Inspection & Test
An AT100 transmitter can be divided up into four major components the float, the sensor, the transmitter,
and the output. All of these components and their subcomponents should be evaluated during each periodic
inspection. This inspection (and possible repair) should take less than 4 hours if the proper tools are made
available. Prior to inspection, the transmitter should be removed from service following end user specified
procedures regarding lockout, tag out, wiring and cleaning. Once removed from service, the AT100 transmitter
should be laid on a flat even surface.

6.4.1 Float Inspection

The AT100 will detect and report the position of the float on its sensor tube as a level of fluid in the process.
In order to measure the fluid in the process properly, the float must move freely up and down the sensor tube
partially submerged in the liquid level. If the float were to become damaged or stuck on the sensor tube, the
transmitter will still report the float position regardless of the actual process fluid level. This by definition is a
Dangerous Undetectable failure.
movement. Some transmitters will have two floats mounted on the sensor tube. This inspection should be done on
both floats.
1) Move the float up and down the length of the sensor tube. It should move freely from the bottom of the sensor tube to
the process connection.
2) Remove the float from the sensor tube by removing the retaining clip or bolt from the end of the transmitter. Inspect
the float for signs of excessive wear or damage.
3) Submerge the float in a container of water to check for leaks as air bubbles escaping from the float. The float is a
sealed unit and any holes in the shell of the float could allow process fluid to seep inside.
Note: K-TEK floats are designed for different specific gravity ranges. The float may or may not float in the water. It may
be necessary to hold the float under the water to perform this test.
Upon completion of float inspection, place the float back on the sensor tube paying carful attention to float
orientation. Some AT100 transmitters will be equipped with float spacers designed to keep the float positioned in the
measurable range of the sensor tube.
reassembled.
AT100-0200-1 Rev L (10-2010) DCN0528
AT100 Suggested Proof Test Table
1
.
2
.
3
of the transmitter over the full working range.
To prevent this failure the float will need to be inspected for integrity and
It is important that the spacer be replaced when the transmitter is
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