Dwyer Instruments PROXIMITY TFLS Series Installation and operating instructions

Series TFLS Tuning Fork Level Switch
Specications - Installation and Operating Instructions
Bulletin L-33-1
Series TFLS Tuning Fork Level Switch is ideal for level control of powders and
ne grained solids, especially those with a low bulk density. Featured in the TFLS is
user-selectable fail-safe operation of the contacts. Unit is not affected by vibration
from conveying systems, motors, or the movement of material. It can be mounted in
any position and is available with factory built extensions for mounting on the top of
the storage vessel.
Series TFLS is easy to use with no calibration required and with no mechanical
moving parts there is no routine maintenance required. The TFLS is unaffected by
the dielectric constant of the sensed material making it superior to a capacitance level
switch for applications where the dielectric constant is too low, where there is more
than one material being used in one vessel, and when material moisture content can
change. The level switch is also good for applications when the bulk density is too low
for a rotating paddle level switch. It can also detect granular material submerged in
liquids of low viscosity, for example sand, gravel, or polyester chips in water.
FEATURES/BENEFITS
• No calibration required
• Vibrating Fork Design: Great for low bulk density and low dielectric constant
products. Will detect products down to 1.8 lb/cu ft (30 g/l)
• Universal Power Supply: One model works from 80-260 VAC and 30 VDC
• Adjustable Sensitivity: Can be set to ignore lighter bulk density products and only
detect heavier products, such as sand in water
• Status Indication: External LED status indicator, and internal indicators for normal
and alarm status
• Failsafe Setting: Output switch can be set for Normally Open or Normally Closed
condition on loss of power
• Time Delay: Prevent false alarms from material surges
SPECIFICATIONS
Service: Dry powder or bulk materials compatible with wetted materials. Can detect
bulk materials submerged in liquid.
Sensitivity: Minimum bulk density of 1.8 lb/ft (30 g/l), maximum particle size 0.4 in
(10 mm).
Wetted Materials: 316 SS.
Temperature Limits: Ambient: -4 to 140˚F (-20 to 60˚C); Process: -4 to 176˚F (-20
to 80˚C).
Pressure Limit: 145 psig (10 bar).
Power Requirement: 80-260 VAC, 50/60 Hz or 16-30 VDC.
Power Consumption: 1 VA.
Enclosure: Aluminum, powder coated.
Enclosure Rating: Weatherproof, NEMA 4X.
Switch Type: SPDT.
Electrical Rating: 7A @ 250 VAC.
Electric Connections: Screw terminals.
Conduit Connection: 3/4˝ female NPT.
Process Connection: 1-1/2˝ male NPT.
Weight: 5.5 lb (2.5 kg).
Indication Lights: External: red LED; Internal: green and red LED’s.
Sensing Delay: (Maximum) covered probe: 2 s; Uncovered probe: 3 to 4 s.
Time Delay: Separate adjustable settings for covering and uncovering the probe,
5 to 25 s.
3/4 CONDUIT
CONNECTION
1-1/2 NPT
7/8 [22.23]
3 [76.20]
"A"
5-3/4 [146.05]
6-13/16 [172.62]
3-5/8
[92.08]
COVER REMOVAL
4-7/8 [123.83]
Ø4-7/16
[112.73]
Extension Length DIM “A”
None
6 in
12 in
18 in
24 in
36 in
48 in
9-1/4 (234.95)
15-7/8 (403.23)
21-7/8 (555.63)
27-7/8 (708.03)
33-7/8 (860.43)
45-7/8 (1165.23)
57-7/8 (1470.03)
PROXIMITY CONTROLS
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A.
Phone: [phone]
Fax: [phone]
www.dwyer-inst.com
e-mail: [email protected]
A DIVISION OF
DWYER INSTRUMENTS, INC.
By Dwyer

OPERATING PRINCIPLE
The TFLS incorporates a piezoelectric crystal that vibrates the fork at its natural
frequency, 85 Hz. When the fork comes in contact with material the vibration is
dampened and the switch changes state. As the fork becomes free of material the
switch changes back to its normal state.
INSTALLATION
Unpacking
Remove the TFLS from the shipping carton and inspect for damage. If damage is
found, notify the carrier immediately.
Mounting Location
The TFLS is rated for industrial environments with few restrictions, however certain
considerations must be made to ensure for optimal sensing and extended operational
life.
• The process temperature and ambient temperature must be with- in the specied
limits for the instrument.
• It is recommended to use a suitable material to protect and seal the process
threads such as TFE tape.
• Position the tines using a wrench on the hexagonal ats above the process
connection. Do not position by turning the housing.
• The probe must be located away from tank inlets or chutes where material may fall
on the probe during lling or emptying (Figure 1, No. 2). If this is not possible a
bafe may be installed above the probe to protect it from falling material (Figure
1, No. 3). The bafe must be installed a minimum of 8” (200 cm), see dimension
A in Figure 1, above the probe so that material will not become packed between the
probe and the bafe.
• For mounting horizontally install with conduit entry facing down so condensate
does not enter the enclosure.
• For mounting horizontally position the tines vertically, narrow edges up, so that
material ows freely through them. The TFLS is designed so that if the conduit
opening is pointed down the tines will be in the proper orientation. No. 6 in Figure
1 shows incorrect mounting, No. 7 correct mounting.
• For mounting horizontally with materials that may stick to the tines it is recommended
to mount the probe angled down so that material slides off easily (Figure 1, No. 7).
• The tines should not be bent, shortened, lengthened, or altered in any way (See
Figure 2).
• For top mounting the tines can be mounted in any position (Figure 1, No. 1).
• When using mounting nozzles, make sure the length is proper so that the tines
extend far enough into the vessel to vibrate free of material buildup on the vessel
wall. Also make sure the nozzle does not extend further than necessary into the
vessel (Figure 1, No. 5).
Figure 1: Installation guide
Figure 2: Fork protection
DO NOT BEND
DO NOT SHORTEN
OR EXTEND
A
1
2
3
4
5
6
7

Wiring
Note: Installation must be made in accordance with National Electric Code and local
codes and regulations. When shing wire through the conduit connection do not allow
the wire to touch or press on components on the boards. Damage to the circuitry may
result.
The TFLS has a 3/4˝ NPT female conduit connection. The conduit connection must
be made such that condensation is not allowed to enter the housing. If nonmetallic
conduit is used, the protective ground may be connected to the external ground
connection screw.
Strip 1/4˝ of insulation from wires. Connect the power wires to terminals 4 and 5 if
powered by 30 VDC and terminals 1, 2, and 3 if powered by 80-260 VAC. Only one
type of power supply may be used at a time, do not connect both AC and DC power
simultaneously. Connect control lines to the relay contact terminals 6, 7, and 8. See
Figure 3 for terminals layout.
CONTROLS AND INDICATORS (See Figure 4)
Time Delay Potentiometers — These controls select the delay times from 5 to 25
seconds from the detection of a level change to the output. There is one setting for wet
delay and one for dry delay.
Dip Switch — This two section switch selects the external LED status and failsafe
mode and sensitivity for different types of material.
Normal LED — Green. This LED is illuminated when the unit is powered and the fork
does not sense any material.
Alarm LED — Red. This LED is illuminated when the relay is powered by the fork
sensing material. It is affected by the delay setting.
External LED — Red. This external LED is illuminated in conjunction with the fork
being covered or uncovered.
SETUP AND CALIBRATION
1. Fail Safe Mode Selection: The relay will always be off when the power fails. In this
case the contacts identied as normally open will be open. The fail safe switch \
selects whether the normally open contacts are open or closed when the probe is
uncovered. There are two options for the failsafe condition that are selected by the
RELAY DIP switch (See Figure 4). Selecting MAX will force the relay contacts to be
open when the probe is uncovered and the NORMAL green LED to be on. Selecting
MIN will energize the relay (closed) when the probe is uncovered and the ALARM
red LED to be on.
EXTERNAL
LED
+-
16... 30 V
DC
80... 260 AC
50/60 HZ
L1 N
12 3456 78 910
RELAY CONTACTS SHOWN FOR
ALARM CONDITION OR POWER OFF.
ALARM STATUS
LED (GREEN)
A
LARM STATUS
LED (RED)
FAILSAFE/SENSITIVIT
Y
WET/DRY DELAY
Figure 4: Switches and LED’s
Figure 3: Terminals
Always install or service this device with the power off and where
required install a disconnect lockout.
WARNING
For power line connections use NEC Class 1 wiring rated 60°/75°C.
Use 12 to 20 AWG copper only for line and load connections. Strip
the wires 1/4˝.
CAUTION

Printed in U.S.A. 5/20 FR# 443478-50©Copyright 2020 Dwyer Instruments, Inc.
PROXIMITY CONTROLS
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A.
Phone: [phone]
Fax: [phone]
www.dwyer-inst.com
e-mail: [email protected]
A DIVISION OF
DWYER INSTRUMENTS, INC.
2. Sensitivity Selection: The sensitivity selection adjusts the fork sensitivity to
material bulk density. The more dense the material, the lower the sensitivity
needed. After installing the probe and making all electrical connections, set the Fail
Safe Selection switch to the MAX position. Set both the wet and dry time delays to
their minimum by rotating them counter-clockwise to the end position. Adjust dip
switch sensitivity to normal (See Figure 4). If there is no material in the tank then
the green LED will be illuminated. Fill the tank so that the fork tines are covered
by material. If the green LED turns off and the red LED turns on then no adjustments
are necessary. If the green LED stays on adjust dip switch sensitivity to sensitive,
the green LED goes out and the red LED comes on. Setting is completed.
3. Time Delay Selection: The time delay is the programmed time between when the
probe senses the presence or absence of material and when the relay changes
state. A time delay is good for applications that could have false or rapid pulsing of
level indications from sloshing or agitated material. Choose a delay setting
appropriate for the specic application. There are two potentiometers for adjusting
the delay time. They are labeled wet and dry, delay, depending on material, and
sets the delay time between when the probe is covered and when the switch
changes state. Adjust the time delay potentiometers by turning them fully counter-
clockwise to their end position. This setting is 5 second delay. To then set a delay
time turn the potentiometer clockwise to the desired time setting. The delay can be
set anywhere from 5 to 25 seconds.
TROUBLE SHOOTING
If the instrument fails rst check that the wiring connections are correct and that the
set up is correct for the application. Next, check to see if the tines vibrate when free
of material.
MAINTENANCE
Upon nal installation of the Series TFLS Tuning Fork Level Switch, no routine
maintenance is required. A periodic check of the system calibration is recommended.
The Series TFLS is not eld serviceable and should be returned if repair is needed
(eld repair should not be attempted and may void warranty). Be sure to include a
brief description of the problem plus any relevant application notes. Contact customer
service to receive a return goods authorization number before shipping.
Condition Relay Status Probable Cause
Probe Covered
Red LED Off
Green LED Off
Terminals 7 and 8 Open
Relay De-energized
No power supplied
Probe Covered
Red LED On
Green LED Off
Terminals 7 and 8 Open
Relay De-energized
Voltage too low
Material too light
Material has formed cavities
Vibration of vessel wall at 85 Hz
Probe Uncovered
Red LED Off
Green LED On
Terminals 7 and 8
Closed
Relay Energized
Heavy material deposit on fork
Fork Damaged
Vibration of vessel wall at 85 Hz