Tek-Trol TEK-LCD 7800A-0L1 User manual

Technology Solutions
www.tek-trol.com
TEK-LCD 7800A-0L1
NEMA 4X Loop Powered Level Indicator
Instruction Manual
Document Number:IM-7800A-0L1

© COPYRIGHT Tek-Trol LLC 2019
NOTICE
Read this manual before working with the product. For personal and system safety, and for optimum
product performance, make sure you thoroughly understand the contents before installing, using, or
maintaining this product.
For technical assistance, contact
Customer Support
796 Tek-Drive
Crystal Lake, IL 60014
USA
Tel: [phone]
www.tek-trol.com
No part of this publication may be copied or distributed, transmitted, transcribed, stored in a
retrieval system, or translated into any human or computer language, in any form or by any means,
electronic, mechanical, manual, or otherwise, or disclosed to third parties without the express
written permission. The information contained in this manual is subject to change without notice.

Table of Contents
1Safety Instructions ........................................................................................................................4
1.1 Installation ....................................................................................................................................... 4
1.2 Unpacking ........................................................................................................................................ 4
1.3 Conduit/Stopping Plug ...................................................................................................................... 4
2Product Description ......................................................................................................................5
2.1 Introduction ..................................................................................................................................... 5
2.2 Specifications.................................................................................................................................... 5
2.3 Dimensional Drawing ........................................................................................................................ 7
2.4 Ordering Information ........................................................................................................................ 8
2.5 Mounting.......................................................................................................................................... 8
2.6 Connections...................................................................................................................................... 8
2.7 Connections & Wiring Diagrams ........................................................................................................ 9
2.8 External Acknowledge Connection .................................................................................................. 10
2.9 Open Collector Output Connections ................................................................................................ 11
3Setup and Programming..............................................................................................................12
3.1 Overview ........................................................................................................................................ 12
3.2 Through-Window Buttons ............................................................................................................... 12
3.2.1 Through-Window Button Operation ......................................................................................................12
3.2.2 Through-Window Button Tips and Troubleshooting..............................................................................12
3.3 Buttons and Display ........................................................................................................................ 13
3.3.1 Menu Button ..........................................................................................................................................13
3.3.2 Right / Reset Button ...............................................................................................................................14
3.3.3 Up / Display Button ................................................................................................................................14
3.3.4 Enter Button ...........................................................................................................................................14
3.4 Main Menu..................................................................................................................................... 14
3.5 Setting Up the Meter (SETUP)........................................................................................................... 15
3.5.1 Setting Numeric Values ..........................................................................................................................16
3.5.2 Setting the Level Decimal Point (DECIMAL)..............................................................................................16
3.5.3 Main Menu Display Functions & Messages............................................................................................16
3.5.4 Scaling the Meter ( ) ....................................................................................................................17
3.5.5 Minimum Input Span..............................................................................................................................18
3.5.6 Scale Error Message (SPN ERR) ...............................................................................................................18
3.5.7 Scaling the Tank Height Indicator (TANK HT)...........................................................................................18
3.5.8 Configuring the Lower Display (DISPLAY) ...............................................................................................18
3.5.9 Setting the Tag........................................................................................................................................19
3.6 Setting Up the Password (PASSWRD) .................................................................................................. 19
3.6.1 Locking the Meter ..................................................................................................................................20
3.6.2 Making Changes to a Password Protected Meter..................................................................................20
3.6.3 Disabling Password Protection...............................................................................................................21
3.7 Advanced Features Menu (ADVANCE)................................................................................................. 22
3.8 Advanced Features Menu & Display Messages................................................................................. 22
3.8.1 Alarm Output (OUTPUT) ...........................................................................................................................24
3.8.2 Input Signal Filter (FILTER) .....................................................................................................................24
3.8.3 Volume Display Scaling (VOLSCAL)...........................................................................................................25

3.8.4 Level Input Live Signal Calibration (LVL CAL)..........................................................................................25
3.8.5 Internal Calibration (ICAL)......................................................................................................................26
3.8.6 Calibration Error Message (Error SPAN) ................................................................................................27
3.8.7 Level Input Multipoint Linearization (MULTIPT) ......................................................................................27
3.8.8 Information (INFO)..................................................................................................................................27
4Operation ...................................................................................................................................28
4.1 Front Panel Buttons Operation........................................................................................................ 28
4.2 Display Maximum, Minimum, and Input Current ............................................................................. 28
4.3 Reset Meter to Factory Defaults ...................................................................................................... 29
4.4 Factory Defaults & User Settings ..................................................................................................... 30
5Troubleshooting .........................................................................................................................31
5.1 Troubleshooting Tips....................................................................................................................... 31
6Quick User Interface Reference ...................................................................................................32

Disclaimer
The information contained in this document is subject to change without notice. Tek- Trol makes no
representations or warranties with respect to the contents hereof; and specifically disclaims any implied
warranties of merchantability or fitness for a particular purpose.
WARNING
•Risk of electric shock or personal injury.
•This product is not recommended for life support applications or applications where
malfunctioning could result in personal injury or property loss. Anyone using this product for
such applications does so at his/her own risk. Tek-Trol LLC shall not be held liable for damages
resulting from such improper use.
•Failure to follow installation guidelines could result in death or serious injury. Make sure only
qualified personnel perform the installation.
CAUTION
Read complete instructions prior to installation and operation of the meter.
Limited Warranty
Tek-Trol LLC warrants this product against defects in material or workmanship for the specified period
under “Specifications” from the date of shipment from the factory.
Tek-Trol’s liability under this limited warranty shall not exceed the purchase value, repair, or
replacement of the defective unit.
Registered Trademarks
All trademarks mentioned in this document are the property of their respective owners.

1Safety Instructions
WARNING
•Read complete instructions prior to installation and operation of the meter.
•Installation and service should be performed only by trained service personnel. Service
requiring replacement of internal components must be performed at the factory.
•Disconnect from supply before opening enclosure. Keep cover tight while circuits are alive.
•If the meter is installed in a high voltage environment and a fault or installation error
occurs, high voltage may be present on any lead.
1.1 Installation
WARNING
Hazardous voltages may exist within enclosure. Installation and service should be performed only
by trained service personnel.
Wiring connectors are accessed by opening the enclosure. To access electrical connectors,
remove the 2 captive screws, then disconnect the ribbon cable from the display module and
set the display module aside.
1.2 Unpacking
Remove the scanner from box. Inspect the packaging and contents for damage. Report
damages, if any, to the carrier. If any part is missing or the scanner malfunctions, please
contact your supplier or the factory for assistance.
1.3 Conduit/Stopping Plug
The Tek-LCD 7800A-0L1 is provided with three ¾ NPT threaded conduit openings and one IP68
rated ¾ NPT plastic conduit plug.
The conduit/stopping plug included has 1.29 wrenching flats and a screwdriver slot.

2Product Description
2.1 Introduction
The Tek-LCD 7800A-0L1 is a plastic field mounted loop-powered meter fully featured for
demanding applications in the harshest environmental conditions. The bar graph representation
of the process input is perfect for level applications and allows for quick assessment of current
conditions. The meter derives all of its power from the 4- 20 mA loop. It is programmed using the
four through-window buttons, without removing the cover, and can be scaled with or without a
calibration signal. The numeric display will read up to 99999 and the alphanumeric display can be
programmed to show any combination of numbers and letters up to seven characters long for use
as engineering units, the process identification tag or a display for the calculated volume when
using for level applications. The backlight lets you see the display under any lighting condition and
can be powered from either the 4-20 mA loop or from a separate DC power supply.
The enclosure has three threaded conduit holes, integrated pipe or wall mounting flanges, and
allows for easy installation of tamper seals.
2.2 Specifications
Except where noted all specifications apply to operation at 25°C (77°F).
GENERAL
DISPLAY
Five Digits Top
Display
(-9999 to 99999)
0.6" (0.05 ft) high, 7-segment, automatic lead
zero blanking.
Seven Characters
0.4" (0.03 ft) high, 14-segment
Symbols
Bar Graph which displays process input from 0-100%
of scaled value.
Backlight
White
DISPLAY UPDATE RATE
Ambient > -13°F (-25°C): 2 Updates/Second
Ambient < -13°F (-25°C): 1 Update/5 Seconds
OVERRANGE
Display flashes 99999
UNDERRANGE
Display flashes -9999
PROGRAMMING
METHOD
Four through-window buttons when cover is installed. Four internal
pushbuttons when cover is removed.
NOISE FILTER
Programmable LO, med, HI, or OFF
RECALIBRATION
Recalibration is recommended at least every 12 months.
MAX/MIN DISPLAY
Max/Min readings reached by the process are stored until reset by the
user or until power to the meter is turned off.
PASSWORD
Programmable password restricts modification of programmed settings.
NON-VOLATILE MEMORY
All programmed settings are stored in non-volatile memory for a minimum
of ten years if power is lost.

NORMAL MODE
REJECTION
64 dB at 50/60 Hz
ENVIRONMENTAL
Operating temperature range: -40°F to 167 °F (-40°C to 75°C)
Storage temperature range: -40°F to 167 °F (-40°C to 75°C)
Relative humidity: 0 to 90% non-condensing
CONNECTIONS
Screw terminals accept 12 to 22 AWG wire
MOUNTING
May be mounted directly to conduit. Two slotted flanges for wall mounting
or NPS 1½" to 2½" or DN 0.13 to 0.21 ft. pipe mounting.
ENCLOSURE
NEMA 4X, IP65 plastic field enclosure. Color: blue. Three ¾" NPT threaded
conduit openings. One ¾" NPT plastic conduit plug, with 1.29 wrenching flats
and a screwdriver slot, is included.
OVERALL DIMENSIONS
5.67 x 5.25 x 4.18 (0.47 ft x 0.43 ft x 0.34 ft) (W x H x D)
WEIGHT
1.65 lbs (26.4 oz, 0.75 kg)
WARRANTY
3 years parts and labor
INPUT
ACCURACY
±0.03% of calibrated span ±1 count, square root & programmable exponent
accuracy range: 10-100% of calibrated span
MULTI-POINT
LINEARIZATION
2 to 32 points
PROGRAMMABLE
EXPONENT
1.0001 to 2.9999
LOW FLOW CUT- OFF
0-99999 (0 disables cutoff function)
TEMPERATURE DRIFT
50 PPM/°C from -40°F to 167 °F (-40°C to 75°C) ambient
DECIMAL POINT
User selectable decimal point
MINIMUM SPAN
Input 1 & Input 2: 0.10 mA
CALIBRATION RANGE
An Error message will appear if input 1 and input 2 signals are too close
together.
Input Range: 4-20 mA, Minimum Span Input 1 & Input 2: 0.10 mA
MAXIMUM VOLTAGE
DROP
Without Backlight or with Externally-Powered (DC Powered) Backlight:
3.0 VDC @ 20 mA
With Loop-Powered Backlight: 6.0 VDC @ 20 mA
EQUIVALENT RESISTANCE
Without Backlight or with Externally-Powered (DC Powered) Backlight:
150 Ω @ 20 mA
With Loop-Powered Backlight: 300 Ω @ 20 mA
EXTERNALLY POWERED
BACKLIGHT
Voltage Range: 9-36 VDC
Maximum Power: 9 VDC (0.2 W), 12 VDC (0.25 W), 24 VDC (0.5 W),

36 VDC (0.75 W),
INPUT OVERLOAD
Over current protection to 2 A max.
OPEN COLLECTOR OUTPUT
RATING
Isolated open collector, 30 VDC @ 150 mA max.
ALARM OUTPUT
Assign to level or volume for high or low alarm trip point.
DEADBAND
0-100% FS, user selectable
ACKNOWLEDGE
Front panel ENTER button and external RESET terminals resets output and
screen indication.
2.3 Dimensional Drawing
Enclosure Dimensions –Front View
Enclosure Dimensions –Side Cross Section View
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 
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2.4 Ordering Information
Popular Model
Model
Description
Tek-LCD 7800A-0L1
NEMA 4X Loop-Powered Level Meter with Bar Graph
Accessories
Model
Description
Tek-LCD 7800A-PLUG75P
¾" NPT Plastic Conduit Plug
Tek-LCD 7800A-6846
Steel Pipe Mounting Kit
Tek-LCD 7800A-6846SS
Stainless Steel Pipe Mounting Kit
2.5 Mounting
The Tek-LCD 7800A-0L1 has two slotted mounting flanges that may be used for pipe mounting or
wall mounting. Alternatively, the unit may be supported by the conduit using the conduit holes
provided.
WARNING
Do not attempt to loosen or remove flange bolts while the meter is in service.
2.6 Connections
WARNING
•Static electricity can damage sensitive components.
•Observe safe handling precautions for static-sensitive components.
•Use proper grounding procedures/codes.
•If the meter is installed in a high voltage environment and a fault or installation error
occurs, high voltage may be present on any lead or terminal.
To access the connectors, remove the enclosure cover and unscrew the two captive screws that
fasten the display module. Disconnect the ribbon cable and remove the display module. Signal
connections are made to a four-terminal connector in the base of the enclosure.
SIGNAL +
4-20 mA signal input positive terminal connection
SIGNAL -
4-20 mA signal return/negative terminal connection when not using loop
powered backlight.
BACKLIGHT +
+9-36 VDC when powering backlight from external supply.
BACKLIGHT -
4-20 mA signal return/negative terminal when using the installed loop powered
backlight or ground/negative when powering backlight from external supply.
OUTPUT+
NPN open collector output positive.

SAFE-TOUCH
BUTTONS
BACKLIGHT
POWER
UNLOCK LOCK
9-36 VDC
LOOP
OUTPUT-
NPN open collector output negative.
RESET +
Contact closure alarm acknowledge pull up to 3 VDC.
RESET-
Contact closure alarm acknowledge ground/negative.
Refer to Figure 1 for terminal positions.
WARNING
Observe all safety regulations. Electrical wiring should be performed in accordance with all
agency requirements and applicable national, state, and local codes to prevent damage to the
meter and ensure personnel safety.
Figure 1. Connector Board
2.7 Connections & Wiring Diagrams
Signal connections are made to a four-terminal connector mounted in the base of the enclosure. For
installations without backlight, only the two signal terminals are connected. The 4-20 mA input with
no backlight has a maximum voltage drop of 3 V and is wired as shown in Figure 2. The loop-powered
backlight configuration requires a total maximum voltage drop of 6 V. The backlight is recommended
for dim lighting conditions and is enabled when wired as shown in Figure 3 or Figure 4.
Figure 2. Connections without Backlight
+
-
+
-
OUTPUT
RESET
+
-
+
-
SIGNAL
BACKLIGHT

Figure 3. Connections with Loop-Powered Backlight
Figure 4. Connections with Externally-Powered Backlight
It is possible to use the same transmitter (signal loop) power supply for the externally powered
backlight. The backlight circuit will draw 25 mA in addition to the loop circuit.
2.8 External Acknowledge Connection
External acknowledge connections are made to two terminals labeled . Connect to a contact
closure source such as a relay or a pushbutton as shown in
Figure 5.
Figure 5. External Alarm Reset/Acknowledge Connections

2.9 Open Collector Output Connections
Output connections are made to two terminals labeled OUTPUT. Connect to an input device such as
alarm indicator as shown in Figure 6, or drive a relay as shown in Figure 7.
WARNING
To avoid damaging the Tek-LCD’s amplifying components, use care not to wire incorrectly or
exceed output ratings. A diode, such as 1N4000 series, will provide protection from relay
transients.
Figure 6. Connection to Device with Internal Pull-Up
Figure 7. Output Connections
5-30 VDC
150 mA MAX
SAFE-TOUCH
BUTTONS
UNLOCK LOCK
9-36 VDC LOOP
BACKLIGHT
POWER
SIGNAL
BACKLIGHT
OUTPUT
RESET
+
+
+
+
-
-
-
-

3Setup and Programming
3.1 Overview
Setup and programming are done through the infrared through-window buttons or using the
mechanical buttons when uncovered. There are two slide switches located on the connector board.
One is used to select backlight power (if equipped) and the other is to lock or unlock the through-
window buttons.
After all connections have been completed and verified, connect the ribbon cable to the display
module, fasten the display module to the base, install enclosure cover, and then apply power.
3.2 Through-Window Buttons
The Tek-LCD 7800A-0L1 is equipped with four sensors that operate as through-window buttons so
that it can be programmed and operated without removing the cover (and exposing the electronics)
in a hazardous area. These buttons can be disabled for security by selecting the LOCK setting on the
SAFE-TOUCH BUTTONS switch located on the connector board in the base of the enclosure.
3.2.1 Through-Window Button Operation
To actuate a button, press and remove one finger to the window directly over the marked button
area. Remove finger to at least 4 inches away from the window in between button activations.
Through-window and mechanical buttons may be held to cycle through menus or digits in place of
repeatedly pushing a button.
The sensors are disabled when a mechanical button is pressed and will automatically be re-enabled
after 60 seconds of inactivity.
3.2.2 Through-Window Button Tips and Troubleshooting
The through-window buttons are designed to filter normal levels of ambient interference and to
protect against false triggering, however it is recommended that the through-window buttons be
turned off (slide SAFE-TOUCH BUTTONS switch to OFF) if there is an infrared interference source in
line-of-sight to the display or if the buttons are not needed.
Through-window button Tips:
•To the extent possible, install the display facing away from sunlight, windows, reflective
objects and any sources of infrared interference.
•Keep the window clean.
•Tighten the cover securely.
•Use a password to prevent tampering.
•If the cover has not been installed and secured tightly, it may take a moment for the
through-window buttons to properly self-calibrate when the cover is tightened.
There is no need to recalibrate the meter for milliamps when first received from the factory.The
meter is factory calibrated for milliamps prior to shipment. The calibration equipment is certified
to NIST standards.

NOTE
Through-window buttons will not work if two or more buttons are detected as being pressed
simultaneously. As a result, be careful to avoid triggering multiple buttons or reaching across
one button location to press another.
3.3 Buttons and Display
3.3.1 Menu Button
•Press the Menu button to enter Programming Mode.
•Press the Menu button during Programming Mode to return to the previous menu selections.
•Hold the Menu button for 1.5 seconds at any time to exit Programming Mode and return to Run
Mode.
•Press and hold the Menu button for 3 seconds to access the Advanced Fea- tures of the

meter.
3.3.2 Right / Reset Button
•Press the Right-arrow button to reset the maximum or minimum value whileit is being displayed
(see Up / Display Button below).
•Press the Right-arrow button to move to the next digit or decimal position during programming.
•Press Right to go backward through most selection menus.
3.3.3 Up / Display Button
•Press Display when in Run Mode to cycle through displaying the maximum value, minimum
value, and the loop input value in mA. The display will time out in 12 seconds. Press Display
again to resume normal lower display oper- ation (lower display will read RESUME).
•Press the Up-arrow button to scroll forward through the menus, decimal point, or to increment
the value of a digit.
3.3.4 Enter Button
•Press the Enter button to access a menu or to accept a setting.
•Press Enter to acknowledge alarm (if enabled).
3.4 Main Menu
The main menu consists of the most commonly used functions: Setup, Advanced,
and Password.
Press MENU button to enter Programming Mode then press the Up-arrow button to scroll
through the main menu.

•Hold MENU, at any time, to exit and return to Run Mode. Changes made to settings prior to pressing
ENTER are not saved.
•Press the MENU button during Programming Mode to return to return to the previous menu
selections.
•Changes to the settings are saved to memory only after pressing ENTER.
•The display moves to the next menu every time a setting is accepted by pressing ENTER.
3.5 Setting Up the Meter (SETUP)
The Setup menu is used to select:
1. Engineering unit’s decimal location
2. Engineering units display scale
3. Tank indicator full and empty values
4. Bottom display selection
Press the ENTER button to access any menu or press UP arrow button to scroll through
choices.
Hold MENU, at any time, to exit and return to Run Mode. Changes made to settings prior to
pressing ENTER are not saved.
Press the MENU button during Programming Mode to return to return to the previous menu
selections.

3.5.1 Setting Numeric Values
The numeric values are set using the RIGHT and UP arrow buttons. Press RIGHT
arrow to select next digit and UP arrow to increment digit. The digit being changed blinks.
Press the ENTER button, at any time, to accept a setting.
Hold MENU, at any time, to exit and return to Run Mode. Changes made to settings prior to
pressing ENTER are not saved.
Press the MENU button during Programming Mode to return to return to the previous menu
selections.
3.5.2 Setting the Level Decimal Point (DECIMAL)
Decimal point may be set with up to four decimal places or with no decimal point.
Pressing the Right arrow moves the decimal point one place to the right and pressing the
Up arrow moves the decimal point one place to the left.
3.5.3 Main Menu Display Functions & Messages
The meter displays various functions and messages during setup, programming, and operation.
The following table shows the main menu functions and messages in the order they appear in the
menu.
Display
Parameter
Action/Setting
SETUP
Setup
Enter Setup menu
DECIMAL
Decimal Point
Enter the decimal point location
SCALE
Scale
Enter the Scale menu for engineering units
INPUT 1
Input 1
Set input 1 value in mA
DSPLY 1
Display 1
Set display 1 engineering units
INPUT 2
Input 2
Set input 2 value in mA
DSPLY 2
Display 2
Set display 2 engineering units
SAVE ?
Save
Save entered scale parameters
SPN ERR
Span Error
Scale point 1 and 2 span error
PERCENT
Percent
Scale the tank indicator full and empty values

0 PCT
0 Percent
Set the tank empty value
100 PCT
100 Percent
Set the tank full value
DISPLAY
Display
Enter Bottom Display menu
TAG
Tag
Display a custom unit or tag
VOLUME
Volume
Display volume
VOL+TAG
Volume + Tag
Display volume and custom tag
PCT HT
Percent Height
Display percent height
PCT+TAG
Percent Height
+ Tag
Display percent height and custom tag
OFF
Off
Disable bottom display
ADVANCE
Advanced
Advanced Features Menu
(See Advanced Features
PASSWRD
Password
Enter the Password menu
UNLOCKD
Unlocked
Program password to lock meter
LOCKED
Locked
Enter password to unlock meter
3.5.4 Scaling the Meter ( )
The 4-20 mA input can be scaled to display the process in engineering units. To scale the meter,
enter the value in milliamps (mA) for input 1, and then the corresponding engineering units display
value. Do the same for input 2.
After entering the display 2 value, confirm the new scale by pressing ENTER at the Save menu.
A signal source is not needed to scale the meter; simply program the inputs and corresponding
display values.
Figure 8. Scale Menu
For instructions on how to program numeric values, see Setting Numeric Values .

For instructions on using multipoint scaling, see Level Input Multipoint Linearization (MULTIPT).
For instructions on how to program numeric values see Setting Numeric Values.
3.5.5 Minimum Input Span
The minimum input span is the minimum difference between input 1 and input 2 signals required
to complete the calibration or scaling of the meter. The minimum span is 0.10 mA.
3.5.6 Scale Error Message (SPN ERR)
If the minimum span is not maintained, the meter will show a span error (SPN ERR) and revert to
input 2, allowing the appropriate input signals to be applied.
3.5.7 Scaling the Tank Height Indicator (TANK HT)
The display includes a 20-segment tank level indicator. This menu sets full and empty values, in
engineering units, for the tank level indicator.
This value may differ from the 20 mA full-scale and 4 mA empty-scale values programmed in the
Scale menu. This is ideal for level transmitters that output less than 20 mA at the maximum height
of the tank or pit or more than 4 mA at the minimum height.
As an example, when using a level transmitter that outputs 20 mA at 25 meters, the tank height
indicator may be set for a maximum of 10 meters. When the meter reaches 10 meters on the
display, the tank height indicator will show full, even though the input is not 20 mA.
3.5.8 Configuring the Lower Display (DISPLAY)
The lower display may be configured to display a custom tag (TAG), volume (VOLUME), volume
and tag (VOL+TAG), percent of full height (PCT HT), or percent of full height and tag (PCT+TAG)
or be blank (OFF).
A custom tag may be up to seven alphanumeric characters programmed for identification
(e.g. TANK 3) or for engineering units (e.g. GALLONS).
Volume is a separate, second scale of the input process variable. This is configured in Volume
Display Scaling (VOLSCAL).
Percent full height shows the percent full of the tank height level indicator programmed in
the Scaling the Tank Height Indicator (TANK HT) menu.
The tank level indicator (GRAPH) may also be turned on or off from the display menu.
10 0
0300 0