AMETEK 952 BlueOx LDT - Manual (Page 26)

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1080 N. Crooks Road • Clawson, MI 48017 • 800.635.0289 • 248.435.0700 • Fax 248.435.8120 • www.AMETEKAPT.com
A.2: Troubleshooting for 952
Analog LDTs
Troubleshooting describes common problems
that can occur when installing the LDT and offers
possible solutions to these problems. If, after
reading this appendix, a problem is still unresolved,
please contact our technical support department.
Troubleshooting is divided into the following two
groups:
• General Checks
• Power Supply
General Checks
Make sure that the magnet is located within the
LDT’s active stroke area. Keep in mind that the
LDT is programmable over the entire active stroke
area. Refer to Section 3.9 for programming details.
Captive magnet assemblies should be positioned
so that they can move freely over the entire area of
the active stroke without binding or pushing on the
rod end. Non-captive magnet assemblies should be
situated so that the magnet is no farther than 0.2”
from the rod at any point in the magnet assembly’s
movement.
NOTE: Ferromagnetic material (material readily
magnetized) should be located no closer than 0.25”
from the magnet or LDT rod end. This includes
mounting brackets, magnet spacers, magnet
brackets, and mounting screws. Ferromagnetic
material can distort the magnetic field, causing
adverse operation or failure of the LDT.
Check all LDT wires for continuity and/or shorts. It
is preferable that the cable between the LDT and
the interface device be one continuous run. If you
are using a junction box, it is highly recommended
that the splice junction box be free of AC and/or
DC transient-producing lines. The shield should
be carried through the splice and terminated at the
interface device end.
Unipolar Power Supply Check
This section will help you to determine if your power
supply is adequate for the LDT to operate properly,
or if the LDT’s cable has a short or open.
In order for the BlueOx to operate properly, the
external power supply must provide a level between
13.5 to 30 VDC. A power supply providing voltage
above this specified range may damage the LDT. A
power supply providing power below this specifed
range will not be sufficient to power the LDT. When
powering more than one BlueOx on a single power
supply, remember that each BlueOx requires three
(3) watts of power. The amount of current draw will
vary based on the input voltage used. To calculate
the current draw for a particular LDT, divide the LDT
wattage by the input voltage. For example, 3 watts
divided by 24 VDC equals 125mA.
If the LDT is not operating properly, the LDT’s cable
may have an open or short, or the power supply is
not supplying sufficient power. To verify this:
1. Turn the power supply off.
2. Remove the mating connector from the LDT.
3. Turn the power supply on.
4. Using a digital voltmeter, check across power
supply common and customer supplied power
(+VDC) on the mating end of the cable for a
level between 13.5 and 30 VDC.
NOTE: LDT’s with potted cable assemblies should
be checked for proper voltage at the power supply
terminals. This cable assembly cannot be removed
from the LDT.
If reading is between 13.5 and 30 VDC, turn power
supply off and go to step 7. If the reading is below
13.5 VDC, either the power supply is not providing
enough power or the LDT’s cable possibly has
a short/open. Reading of no voltage or minimal
voltage (less than 5 volts) may be due to a short/
open in the cable. If reading is not between 13.5
and 30 VDC, go to step 5. If reading is above 30
VDC, adjust power supply or replace.