Precision Digital PD6720 User guide

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PD6720 Field-Mount Loop-Powered Rate/Totalizer
Instruction Manual
PRECISION DIGITAL CORPORATION
233 South Street • Hopkinton MA 01748 USA Tel (800) 343-1001 • Fax (508) 655-8990
www.predig.com
• NEMA 4X, IP66 Loop-Powered Field-Mount Rate/Totalizer
• 4-20 mA Input with ±0.03% Accuracy
• 3.0 Volt Drop (6.0 Volt Drop with Backlight)
• Easy Field Scaling in Engineering Units without Applying an Input
• 0.7" (17.8 mm) 5 Digits Upper Display for Rate
• 0.4" (10.2 mm) 7 Alphanumeric Characters Lower Display for Total, Tag, or Units
• Simultaneous 5-Digit Rate and 7-Digit Total Display
• Rate in Units per Second, Minute, Hour, or Day
• Display Open Channel Flow with Programmable Exponent Feature
• Open Collector Pulse or Alarm Output
• Display Mountable at 0°, 90°, 180°, & 270°
• SafeTouchTM Through-Window Button Programming
• HART® Protocol Transparent
• Loop or External DC-Powered Backlight Standard
• Operating Temperature Range: -40 to 75°C (-40 to 167°F)
• Conformal Coated PCBs for Dust and Humidity Protection
• Password Protection for Programming Only
• 32-Point Linearization, Square Root Extraction and Programable Exponent Function
• Wide Viewing Angle
• Flanges for Wall or Pipe Mounting
• Plastic NEMA 4X, IP66 Enclosure
• Three 3/4" NPT Threaded Conduit Openings (Two Plugs Installed)
• Stainless Steel Tag Available
• 2" U-Bolt Kits Available
• 3-Year Warranty
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PD6720 Field-Mount Loop-Powered Rate/Totalizer
Instruction Manual
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Disclaimer
The information contained in this document is subject to change without notice. Precision Digital Corporation 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.
• Read complete instructions prior to installation and operation of the meter.
• 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. Precision Digital Corporation 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.
WARNING
Cancer and Reproductive Harm - www.P65Warnings.ca.gov
Limited Warranty
Precision Digital Corporation warrants this product against defects in material or workmanship for the specified period under
“Specifications” from the date of shipment from the factory. Precision Digital’s liability under this
limited warranty shall not exceed the purchase value, repair, or replacement of the defective unit. See Warranty Information and Terms & Conditions on www.predig.com for complete details.
© 2020 Precision Digital Corporation. All rights reserved.

Introduction

The PD6720 is a rugged, field-mount, loop-powered rate/totalizer fully featured for demanding applications in harsh environmental conditions. The meter derives all of its power from the 4-20 mA loop. It is programmed using the four SafeTouch through-window buttons, without removing the cover, and can be scaled with or without a calibration signal. The numeric rate display will read up to 99999 and the alphanumeric total/tag display will read up to
9999999. The alphanumeric display can also be programmed to show any combination of numbers and letters up to seven characters long for use as engineering units and/or the process identification tag. 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 is provided with three threaded conduit holes and integrated pipe or wall mounting slotted flanges.

Ordering Information

Model
Description
PD6720-0K1
Field-Mount Loop-Powered Rate/Totalizer with Backlight
Accessories
Model
Description
PDAPLUG75P
3/4" NPT Plastic Conduit Plug
PDA1024-01
24 VDC Power Supply for DIN Rail
PDA6846
Steel 2" U-Bolt Kit. All Material: Zinc Plated Steel; (1) U-Bolt for 2" Pipe with (2 each) Washers, Lock Washers, and Nuts.
PDA6846-SS
Stainless Steel 2" U-Bolt Kit. All Material: Stainless Steel; (1) U-Bolt for 2" Pipe with (2 each) Washers, Lock Washers, and Nuts.
PDA-SSTAG
Custom Stainless Steel Tag (see website for convenient ordering form)
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Instruction Manual
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Table of Contents
Introduction .......................................................................................................... 2
Ordering Information ........................................................................................... 2
Specifications....................................................................................................... 5
General ............................................................................................................. 5
Input .................................................................................................................. 5
Rate/Totalizer ................................................................................................... 6
Open Collector Output .................................................................................... 6
Safety Information ............................................................................................... 7
Installation ............................................................................................................ 7
Unpacking ........................................................................................................ 7
Pre-Installed Conduit Plug .............................................................................. 7
Mounting .......................................................................................................... 7
Dimensions ...................................................................................................... 7
Connections ..................................................................................................... 8
Wiring Diagrams .............................................................................................. 9
External Reset Connection............................................................................ 9
Open Collector Output Connections.............................................................. 9
Setup and Programming ................................................................................... 10
Overview ......................................................................................................... 10
SafeTouch Buttons ........................................................................................ 10
SafeTouch Button Tips and Troubleshooting .............................................. 10
Buttons and Display ...................................................................................... 11
Main Menu Display Functions & Messages ................................................ 12
Main Menu ...................................................................................................... 12
Setting Up the Meter (SETUP) ........................................................................ 13
Setting Numeric Values ............................................................................... 13
Setting the Decimal Point (dec.PT) .............................................................. 13
Programming the Meter (Prog) ................................................................... 14
Setting the Time Base (t.base) ................................................................... 15
Setting the Total Conversion Factor (totCF) .............................................. 15
Manual or Automatic Total Reset Function (t rST) .................................... 16
Setting the Tag Display (tag) ...................................................................... 16
Setting Up the Password (PASSWRD) ........................................................... 17
Locking the Meter ........................................................................................ 17
Making Changes to a Password Protected Meter ....................................... 17
Disabling Password Protection.................................................................... 17
Service Feature (SERVICE)............................................................................. 17
Advanced Features Menu ............................................................................. 18
Advanced Features Menu & Display Messages......................................... 18
Alarm & Pulse Output (OUTPUT) .................................................................. 19
Advanced Function Selection (FUNCTN) ...................................................... 20
Multi-Point Linearization (lnear) ................................................................. 20
Multi-Point Scaling (SCALE) ......................................................................... 20
Multi-Point Calibration (CAL) ........................................................................ 20
Square Root Linearization (Squar) ............................................................. 20
Low-Flow Cutoff (CUTOFF) ........................................................................... 20
Programmable Exponent Linearization (Prog.E)......................................... 21
Internal Calibration (ICAL) ........................................................................... 21
Operation ............................................................................................................ 22
Front Panel Buttons Operation .................................................................... 22
Maximum & Minimum Readings (MAXIMUM & MINIMUM) .............................. 22
Reset Meter to Factory Defaults ................................................................... 22
Factory Defaults & User Settings
................................................................. 22
Troubleshooting................................................................................................. 23
Troubleshooting Tips .................................................................................... 23
Quick User Interface Reference........................................................................ 24
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Table of Figures
Figure 1. Enclosure Dimensions – Front View .................................................... 7
Figure 2. Enclosure Dimensions – Side Cross Section View ............................ 7
Figure 3. Connector Board.................................................................................... 8
Figure 4. Connections without Backlight ............................................................ 9
Figure 5. Connections with Loop-Powered Backlight ........................................ 9
Figure 6. Connections with Externally-Powered Backlight.................................. 9
Figure 7. Reset Connections ................................................................................ 9
Figure 8. Connection to Device with Internal Pull-Up ........................................ 9
Figure 9. Output Connections .............................................................................. 9
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Specifications

Except where noted all specifications apply to operation at +25°C.

General

Display
Five digits (-9999 to
99999)
0.70" (17.8 mm) high, 7-segment, automatic lead zero blanking.
Seven characters
0.4" (10.2 mm) high, 14-segment. Symbols
High & Low Alarm, Password Lock
Display Orientation
Display may be mounted at 90° increments up to 270° from default orientation.
Display Assignment
Upper display is assigned to rate and lower display may be assigned to total, tag name/ engineering units, or to alternate between them.
Display Update Rate
Ambient > -25°C: 2 Updates/Second Ambient < -25°C: 1 Update/5 Seconds
Backlight
White; Loop-powered or externally powered. Backlight can be enabled or disabled via alternative wiring of terminal block. Loop­powered backlight brightness will increase as the input signal current increases. Externally powered backlight has consistent brightness.
Externally Powered Backlight
Voltage Range:
Maximum Power
9-36 VDC 9 VDC
12 VDC
24 VDC
36 VDC
0.2 W 0.25 W
0.5 W 0.75 W
Display Overrange
Display flashes 99999
Display Underrange
Display flashes -9999
Programming Method
Four SafeTouch 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.
Advanced Function
Linear, square root, or programmable exponent
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 to 75°C Storage temperature range: -40 to 75°C Relative humidity: 0 to 90% non-condensing
Connections
Screw terminals accept 12 to 22 AWG wire
Enclosure
NEMA 4X, IP65 plastic field enclosure Color: grey Three ¾" NPT threaded conduit openings. Two ¾" NPT plastic conduit/stopping plug with
1.29" wrenching flats and screwdriver slot.
Mounting
May be mounted directly to conduit. Two slotted flanges for wall mounting or NPS 1½" to 2½" or DN 40 to 65 mm pipe mounting. See Dimensions on page 7.
Overall Dimensions
5.67" x 5.25" x 4.18" (W x H x D) (144 mm x 133 mm x 106 mm)
Weight
1.65 lbs (26.4 oz, 0.75 kg)
Warranty
3 years parts and labor. See Warranty Information and Terms & Conditions on
www.predig.com for complete details.

Input

Input
4-20 mA
Accuracy
±0.03% of calibrated span ±1 count, square root & programmable exponent accuracy range: 10-100% of calibrated span.
Temperature Drift
50 PPM/C from -40 to 75C ambient
Maximum Voltage Drop & Equivalent Resistance
Without Backlight or with Externally Powered Backlight
With Loop­Powered Backlight
3.0 VDC @ 20 mA
6.0 VDC @ 20mA
150 Ω @ 20 mA
300 Ω @ 20 mA
Multi-Point Linearization
2 to 32 points
Signal Input Conditioning
Linear, square root, programmable exponent
Programmable Exponent
User selectable from 1.0001 to 2.9999 for open channel flow.
Low Flow Cutoff
0-99999 (0 disables cutoff function) Point below at which display always shows zero.
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
Minimum Span Input 1 & Input 2
4-20 mA
0.10 mA
Input Overload
Over current protection to 2 A max.
HART Transparency
The meter does not interfere with existing HART communications; it displays the 4-20 mA primary variable and it allows the HART communications to pass through without interruption. The meter is not affected if a HART communicator is connected to the loop. The meter does not display secondary HART variables.
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Instruction Manual
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Rate/Totalizer

Rate Display
0 to 99,999 leading zero blanking
Total Display
0 to 9,999,999 leading zero blanking
Total Decimal Point
Up to six decimal places or none: d.dddddd, d.ddddd, d.dddd, d.ddd, d.dd, d.d, or ddddddd
Lower Display Configuration
Can be programmed to display total, tag name/engineering units, or to alternate between them.
Totalizer
Calculates total based on rate, time base of second, minute, hour, or day, and field programmable multiplier; stored in non-volatile memory upon power loss.
Totalizer Reset
Via front panel SafeTouch button, time delay, external contact closure, or protected
Total Conversion Factor
0.000001 to 9,999,999
Totalizer Rollover
Display rolls over when display exceeds 9,999,999. Relay status reflects the displayed value.
Total Reset Delay
Programmable from 0 to 99,999 seconds

Open Collector Output

Rating
Isolated open collector, sinking NPN 30 VDC @ 150 mA max.
Alarm Output
Assign to rate for high or low alarm trip point. Assign to total for total alarm trip point.
Deadband
0-100% FS, user selectable
Acknowledge
Front panel ACK button resets output and screen indication.
Pulse Output Scaler (Count)
The pulse output scaler (count) is programmable from 0.0001 to 99999. One pulse is generated for every total increment selected (e.g. A pulse scaler value of 100 will generate one pulse every time the total is incremented by 100 units). If the pulse output exceeds the programmed output frequency, pulses are accumulated as pending and are not lost. Pulses will continue to output until the buffer is emptied or the total is reset from the front panel.
Pulse Output Frequency
Programmable frequency: 2, 4, 8, 16, 32, 64, 128 Hz. Minimum pulse width: 3.9 ms @ 128 Hz Maximum pulse width: 250 ms @ 2 Hz Factory default pulse width: 31 ms @ 16 Hz
EFT
±2 kV DC mains, ±1 kV other
Telco Surge
±1 kV
CRFI
3 V, 0.15-80 MHz, 1 kHz 80% AM
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Instruction Manual
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Safety Information

• 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.
• 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.

Installation

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.

Unpacking

Remove the meter from box. Inspect the packaging and contents for damage. Report damages, if any, to the carrier.
If any part is missing or the meter malfunctions, please contact your supplier or the factory for assistance.

Pre-Installed Conduit Plug

The PD6720 is supplied with two pre-installed conduit plugs for installations that do not require the use of all three conduit entries.

Mounting

The PD6720 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.
Refer to Figure 1 and Figure 2.
• Do not attempt to loosen or remove flange bolts while the meter is in service.

Dimensions

All units: inches [mm]
Figure 1. Enclosure Dimensions – Front View
Figure 2. Enclosure Dimensions –
Side Cross Section View
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Connections

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.
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 3 for terminal positions.
• 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.
• 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.
Figure 3. Connector Board
SAFE-TOUCH
BUTTONS
BACKLIGHT
POWER
UNLOCK LOCK
LOOP
9-36 VDC
+
-
+
-
SIGNAL BACKLIGHT
+
-
+
-
OUTPUT RESET
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Instruction Manual
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Wiring Diagrams

Signal connections are made to a four-terminal connector mounted in the base of the enclosure per Figure 3. Connector Board. The enclosure also provides one internal and one external earth grounding screw.
For installations that don’t use the backlight, the
maximum voltage drop is 3 V and connections are made per Figure 4.
For installations that use the backlight powered from the meter, the maximum voltage drop is 6 V and connections are made per Figure 5. For installations that use the backlight powered from an external source, the maximum voltage drop is 3 V and connections are made per Figure 6.
Figure 4. Connections without Backlight
Figure 5. Connections with Loop-Powered Backlight
Loop-powered backlight brightness will increase as the input signal current increases. If constant backlight brightness is desired, the backlight should be powered by an external source.
Figure 6. 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.

External Reset Connection

External reset connections are made to two terminals labeled RESET. Connect to a contact closure source such as a relay or a pushbutton as shown in Figure 7.
Figure 7. Reset Connections

Open Collector Output Connections

Output connections are made to two terminals labeled OUTPUT. Connect to an input device such as alarm indicator or pulse counter as shown in Figure 8 or drive a relay as shown in Figure 9.
To avoid damaging the PD6720’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 8. Connection to Device with Internal Pull-Up
Figure 9. Output Connections
4-20 mA
Transmitter
+
-
+
-
SIG NAL BACKLIG HT
Power
Supply
UNLOCK LOCK
SAFE -TOUCH
BUTTONS
LOOP9-36
VDC
BACKLIG HT
POW ER
+
-
+
-
OU TPUT RESET
UNLOCK LOCK
SAFE-TOUCH
BUTTONS
LOOP9-36
VDC
BACKLIG HT
POW ER
4-20 mA
Transmitter
+
-
+
-
SIGN AL BACKLIG HT
Slide Switch to
LOOP
Power
Supply
+
-
+
-
OU TPUT RESET
4-20 mA
Transmitter
+-+
-
SIGN AL B ACKL IGHT
Slide Switch to
9-36 VDC
Power Supply
Power
Supply
+
-
+
-
OU TPUT RESET
UNLOCK LOCK
SAFE-TO UCH
BUTTONS
LOOP9-36
VDC
BACKLIG HT
POW ER
+
-
+
-
SIGN AL BACKLIGHT
+
-
+
-
OU TPUT RESET
UNLOCK LOCK
SAFE-TOUCH
BUTTONS
LOOP9-36
VDC
BACKLIGHT
POW ER
+
-
+
-
SIGNAL BAC KLIGHT
+
-
+
-
OUT PUT RESET
+
Alarm Indicator/ Pulse Counter (e.g. PD6300)
-
UNLOCK LOCK
SAFE-TO UCH
BUTTONS
LOOP9-36
VDC
BACKLIG HT
POW ER
+-+
-
SIGNAL BAC KLIGHT
+-+
-
OU TPUT RESET
UNLOCK LOCK
SAFE-TO UCH
BUTTONS
LOOP9-36
VDC
BACKLIG HT
POW ER
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PD6720 Field-Mount Loop-Powered Rate/Totalizer
Instruction Manual
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Setup and Programming

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 traceable to NIST standards.

Overview

Setup and programming is done through the infrared through-window SafeTouch 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 and the other is to lock or unlock the SafeTouch 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.

SafeTouch Buttons

The PD6720 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 to the environment. These buttons can be disabled for security by selecting the LOCK setting on the switch located on the connector board in the base of the enclosure. To actuate a button, press one finger to the window directly over the marked button area. When the cover is removed, the four mechanical buttons located next to the sensors are used. The sensors are disabled when a mechanical button is pressed and will automatically be re-enabled after 60 seconds of inactivity.
The SafeTouch buttons are designed to filter normal levels of ambient interference and to protect against false triggering, however, it is recommended that the SafeTouch buttons be disabled (slide switch to LOCK) if there is an infrared interference source in line-of­sight to the display.

SafeTouch Button Tips and Troubleshooting

The SafeTouch buttons are designed to filter normal levels of ambient interference and to protect against false triggering, however, it is recommended that the SafeTouch buttons be disabled (slide switch to LOCK) if there is an infrared interference source in line-of­sight to the display.
SafeTouch Button Tips:
• To remove cover with power applied or to clean the window, select SERVICE in the main menu before opening the cover. This will temporarily disable the SafeTouch buttons for 60 seconds to prevent inadvertent use. Use the mechanical buttons while the meter is open.
• 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.
After all connections have been completed and verified, apply power to the loop.
• SafeTouch 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.
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Buttons and Display

Button Symbol
Description
Symbol
Status
Menu
HI
High
Alarm Set
Right arrow/ Reset
LO
Low Alarm
Set
Up arrow/ Display
SET
Total
Alarm Set
Enter
Password
Enabled
Menu Button
• Press the Menu button to enter or exit the Programming Mode at any time.
• Press and hold the Menu button for five seconds to access the Advanced features of the meter.
Right / Reset Button
• Press the Right arrow button to move to the next digit or decimal position during programming.
Up / Display Button
• Press the Up arrow button to scroll through the menus, decimal point, or to increment the value of a digit.
Enter Button
• Press the Enter button to access a menu or to accept a setting.
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.
MENU
RESET
DISPLAY
ENTER
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Main Menu Display Functions & Messages

The meter displays various functions and messages during setup, programming, and operation. The table in the right column shows the main menu functions and messages in the order they appear in the menu.

Main Menu

The main menu consists of the most commonly used functions: Setup, Password, and Service.
Press MENU button to enter Programming Mode then press the Up Arrow button to scroll through the main menu.
• Press MENU, at any time, to exit and return to Run Mode. Changes made to settings prior to pressing Enter are not saved.
• 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.
Display
Parameter
Action/Setting
SETUP
Setup
Enter Setup menu
DeC..pt
Decimal point
Enter Decimal Point menu
Rate
Rate decimal
Set rate display decimal point
total
Total decimal
Set total display decimal point
PRoG
Program
Enter the Program menu
sCalE
Scale
Enter the Scale menu
Cal
Calibrate
Enter the Calibrate menu
Inpt1
Input 1
Calibrate input 1 signal or program input 1 value
DspL1
Display 1
Program display 1 value
Inpt2
Input 2
Calibrate input 2 signal or program input 2 value
DsPl2
Display 2
Program display 2 value
Span
Error
Span Error
Error, calibration not successful, check signal
TbASE
Time Base
Enter the Time Base menu
sec
Second
Units per second
min
Minute
Units per minute
hour
Hour
Units per hour
day
Day
Units per day
TotCF
Conversion Factor
Enter the Conversion Factor menu
T rST
Total Reset
Enter the Total Reset menu
Auto
Automatic
Automatic Total Reset
T DELAY
Time Delay
Automatic Reset Time Delay
man
Manual
Manual Total Reset
Enabl
Enable
Enable Manual reset
dsabl
Disable
Disable Manual reset
tag
Tag/Units
Enter the Tag/Units Menu
ON
Tag On
Enable Tag/Units
OFF
Tag Off
Disable Tag/Units
togle
Tag Toggle
Toggle Tag and Total
PASSWRD
Password
Enter the Password menu
UNLOCKD
Unlocked
Program password to lock meter
LOCKED
Locked
Enter password to unlock meter
99999
-99999
Flashing display
Overrange condition Underrange condition
SERVICE
Service
Select before removing/installing cover for service or to clean the window
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Setting Up the Meter (SETUP)

The Setup menu is used to select:
1. Rate and total decimal point position
2. Program menu
3. Rate and total tag display
4. Time base
5. Total conversion factor
6. Manual or automatic total reset function
Press the Enter button to access any menu or press Up arrow button to scroll through choices.
Press the Menu button to exit at any time.

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 or MENU button to exit without saving changes.
The decimal point is set using the Right or Up arrow button in the Setup-decimal point menu.

Setting the Decimal Point (dec.PT)

Rate decimal point may be set with up to four decimal places or with no decimal point at all. Total decimal point may be set with up to six decimal places or with no decimal point at all. Rate decimal and total decimal are programmed individually.
Pressing the Right arrow moves the decimal point one place to the right until no decimal point is displayed.
Pressing the Up arrow moves the decimal point one place to the left.
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Programming the Meter (Prog)

The meter may either be scaled (SCALE) without applying an input or calibrated (Cal) by applying an input. The meter comes factory calibrated to NIST standards, so for initial setup, it is recommended to use the (SCALE) function. The Program menu contains the Scale (SCALE) and the Calibrate (Cal) menus. Process inputs may be scaled or calibrated to any display within the range of the meter.
Note: The Scale and Calibrate functions are exclusive of each other. The meter uses the last function programmed. Only one of these methods can be employed at a time. The Scale and Calibrate functions can use up to 32 points (default is 2). The number of points should be set in the Advanced Features menu under the Multi-Point Linearization (lnear) menu selection prior to scaling and calibration of the meter, see Advanced Features Menu, page 18.
Scaling the Meter (SCale)
The 4-20 mA input can be scaled to display the process in engineering units.
A signal source is not needed to scale the meter; simply program the inputs and corresponding display values.
For instructions on how to program numeric values see Setting Numeric Values, page 13.
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Calibrating the Meter (Cal)
To scale the meter without a signal source refer to Scaling the Meter (SCale).
The meter can be calibrated to display the process in engineering units by applying the appropriate input signal and following the calibration procedure.
The use of a calibrated signal source is strongly recommended.
1. Press the Up arrow button to scroll to the Calibration menu (CAL) and press Enter.
2. The meter displays Inpt1. Apply a known signal and press Enter. The display will flash while accepting the signal.
3. After the signal is accepted, the meter displays dspl1 Press Enter. Enter a corresponding display value for the signal input, and press Enter to accept.
4. The meter displays Inpt2. Apply a known signal and press Enter. The display will flash while accepting the signal.
5. After the signal is accepted, the meter displays dspl2. Press Enter. Enter a corresponding display value for the signal input and press Enter to accept.
After completing calibration the save? display will need to be acknowledged using the Enter key before calibration will take effect.
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.
If the minimum span is not maintained, the meter reverts to input 2, allowing the appropriate input signals to be applied.
Re-Calibrating the Internal Calibration Reference (ICaL)
The Internal Calibration (ICAL) menu, located in the Advanced features menu, is used to recalibrate the
internal calibration reference. Recalibration is recommended at least every twelve months. Refer to
Input Signal Filter (FILTER) The noise filter is available for unusually noisy signals
that cause an unstable process variable display. The noise filter averages the input signal over a certain period. The filter level can be set to low (LO), medium (med), high (HI), or off (OFF). The higher the filter setting, the longer the averaging time and so the longer the display may take to find its final value. The filter contains a noise filter bypass feature so that while small variations in the signal will be filtered out, large, abrupt changes to the input signal are displayed immediately.
Internal Calibration (ICAL) page 21 for instructions.

Setting the Time Base (t.base)

The meter calculates total based on rate and a time base of units per second, minute, hour, or day.
Press the Enter button, at any time, to accept a setting or Menu button to exit without saving changes.

Setting the Total Conversion Factor (totCF)

Total Conversion Factor is used to convert to a different unit of total display. For example, to display
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rate in gallons and total in liters, enter a conversion factor of 3.7854. When rate and total units are the same, the Conversion Factor should be 1.0000.
Press the Enter button, at any time, to accept a setting or Menu button to exit without saving changes.

Manual or Automatic Total Reset Function (t rST)

The meter may be programmed to reset the total either manually using the Reset button or automatically. Manual reset button may be disabled to avoid inadvertent total reset.
The automatic reset is based on the set point programmed in the Advanced menu: OUTPUT alrm total. Once the set point is reached, the meter waits for a programmed amount of time (t dly) and then resets the total to zero.
• To enable total reset by Reset button, choose man Enabl.
• To disable total reset by Reset button, choose man dsabl.
• To reset total upon total alarm set point, choose auto, enter a time delay (t dly), and proceed to programming the set point, see Alarm Output (alrm) on page 19.
Press the Enter button, at any time, to accept a setting or Menu button to exit without saving changes.

Setting the Tag Display (tag)

The meter can be set to display a combination of seven alphanumeric characters for engineering units (e.g. GALLONS) or for identification (e.g. TANK 3).
Press Right arrow to select next unit and Up arrow to increment unit.
• To automatically cycle the lower display between total reading for ten seconds and tag for two seconds, choose tOgle.
• To disable the tag display and show only total reading uninterrupted on the lower display, choose Off.
• To show tag only on the lower display choose On. Totalizing continues in the background, but it is not shown while On is selected.
Selecting On or togle prompts for entry of the tag. The unit being changed blinks. Press the Enter button, at any time, to accept a
setting or Menu button to exit without saving changes.
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Setting Up the Password (PASSWRD)

The Password menu is used to program a five-digit password to prevent unauthorized changes to the programmed parameter settings. The lock symbol is displayed to indicate that settings are protected.

Locking the Meter

Enter the Password menu and program a five-digit password.
For instructions on how to program numeric values see Setting Numeric Values, page 13.
Record the password for future reference. If appropriate, it may be recorded in the space provided.
Model:
Serial Number:
Password:
__ __ __ __ __
Additional parameters, not needed for most applications, are programmed with the Advanced features menu, see Advanced Features Menu on page 18.

Making Changes to a Password Protected Meter

If the meter is password protected, the meter will display the message LOCKED when the Menu button is pressed. Press the Enter button while the message is being displayed and enter the correct password to gain access to the menu. After exiting the programming mode, the meter returns to its password protected condition.

Disabling Password Protection

To disable the password protection, access the Password menu and enter the correct password twice, as shown below. The meter is now unprotected until a new password is entered.
If the correct six-digit password is entered, the meter displays the message UNLOCKD (unlocked) and the protection is disabled until a new password is programmed.
If the password entered is incorrect, the meter displays the message LOCKED for about two seconds, and then it returns to Run Mode. To try again, press Enter while the Locked message is displayed.
Did you forget the password?
The password may be disabled by entering a master password. If you are authorized to make changes, enter the master password 50865 to unlock the meter.

Service Feature (SERVICE)

Select SERVICE from the main menu to temporarily disable the SafeTouch buttons to prevent inadvertent use. Buttons will automatically resume operation after 60 seconds. The display blinks the message SERVICE during this period. This should be used when cleaning the window and when installing or removing the cover while power is applied.
The service menu is not shown when the SafeTouch buttons are disabled using the slide switch located on the connector board.
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Advanced Features Menu

To simplify the setup process, functions not needed for most applications are located in the Advanced features menu. Press and hold the MENU button for five seconds to access the Advanced features menu.
Press the Enter button to access any menu or press
Up arrow button to scroll through choices. Press the Menu button to exit at any time.

Advanced Features Menu & Display Messages

The following table shows the Advanced features menu functions and messages in the order they appear in the menu.
Display
Parameter
Action/Setting
OUTPUT
Output
Enter output menu
OFF
Off
Disable output
Alrm
Alarm Output
Enter alarm output menu
Rate
Rate Alarm
Assign alarm output to rate
Total
Total
Assign alarm output to total
Set
Set Point
Program set point
Reset
Reset Point
Program reset point
Pulse
Pulse Output
Program pulse output Scaler (Count)
MAX HZ
Frequency
Program pulse output maximum frequency
Funct
Function
Enter advanced function menu
Lnear
Linear
Set linear scaling
Squar
Square Root
Set square root extraction
Prog..E
Programmable Exponent
Set programmable exponent
CUTOFF
Low-Flow Cutoff
Set low-flow cutoff
FILTER
Filter
Set noise filter
OFF
Filter Off
Disable noise filter
LO
Filter Low
Set noise filter to low setting
mED
Filter Medium
Set noise filter to medium setting
HI
Filter High
Set noise filter to high setting
ICAL
Internal Calibration
Enter internal reference calibration
INFO
Meter Information
Show software number and version, or reset to factory defaults
SFT
Software
Software number
ver
Software Version
Software version
RESET DFALTS?
Reset Defaults
Restore factory default parameter settings
For instructions on how to program numeric values see Setting Numeric Values, page 13.
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Alarm & Pulse Output (OUTPUT)

The PD6720 is equipped with an NPN open collector output that may be set up for high or low rate alarm trip point, total alarm trip point, or pulse output based on K-factor. The pulse output frequency may be programmed for 2, 4, 8, 16, 32, 64, or 128 Hz.
The output may be disabled by selecting off. When alarm indication is enabled, the HI and LO symbols are used accompanied by a flashing display. The alarm status will show on the display even if the output is not wired.
Alarm Output (alrm)
• Rate high alarm trip point: program set point above reset point.
• Rate low alarm trip point: program set point below reset point.
• Rate alarm deadband is determined by the difference between set and reset points. Minimum deadband is one display count. If set and reset points are programmed the same, output will reset one count below set point.
• Total alarm trip point: program total set point. Alarm reset is triggered by total reset (There is no reset parameter entered for total). If automatic total reset is enabled, this setting will be the trigger point for the timer. It is not necessary to
have the output wired for automatic reset function to work.
To acknowledge an alarm, press the Enter button once for acknowledge prompt and a second time to confirm.
Pulse Output Scaler (count)
The pulse output scaler (count) corresponds to the total units (e.g. gallons) needed to generate one pulse. For example, if the pulse output scaler (count) value is set to 10; one pulse is generated for every 10 counts incremented on the display.
If the pulse output exceeds the programmed output frequency, pulses are accumulated as pending. Pulses will continue to output until the buffer is emptied or the total is reset from the front panel.
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Advanced Function Selection (FUNCTN)

The Advanced Function menu is used to select the advanced function to be applied to the input: linear, square root, programmable exponent, or round horizontal tank volume calculation. The multi-point linearization is part of the linear function selection.
Meters are set up at the factory for linear function with 2-point linearization. The linear function provides a display that is linear with respect to the input signal.

Multi-Point Linearization (lnear)

Up to 32 linearization points can be selected under the Linear function. The multi-point linearization can be used to linearize the display for non-linear signals such as those from level transmitters used to measure volume in odd-shaped tanks or to convert level to flow using weirs and flumes that require a complex exponent. These points are established via direct entry (SCALE) or with a live calibration signal source (CAL).

Multi-Point Scaling (SCALE)

The multi-point scaling is entered after selecting the number of points (noPtS). The input signal levels (InP 1-32) for up to 32 points, along with the corresponding meter reading (dSP 1-32) should be entered for each linearization point.

Multi-Point Calibration (CAL)

The meter can be calibrated using a current source instead of using input scaling. This process will override previously programmed scaling points. Apply a live signal using a known accurate signal source (InP 1-32) and then enter the corresponding meter reading (disp 1-32) for that input signal level.
The use of a calibrated signal source is strongly recommended.
Important Navigation Note
After entering the last display value, the linearization entries must be saved (SAUE?) before they are put into effect. However, you may move past this selection using the Up arrow key if you need to go back and correct and earlier entry. Once confident in the entries, you must navigate back to the Save menu screen (SAUE?) and press the Enter key to save the changes.

Square Root Linearization (Squar)

The square root function can be used to linearize the signal from a differential pressure transmitter and display flow rate in engineering units.
PD6720 Displaying Flow Rate by Extracting Square Root
from DP Transmitter Signal.

Low-Flow Cutoff (CUTOFF)

The low-flow cutoff feature allows the meter to be programmed so that the often-unsteady output from a differential pressure transmitter, at low flow rates, always displays zero on the meter. The default cutoff is zero to prevent negative readings, but this may be overridden to allow them.
The cutoff value may be programmed from -0 to
99999. Below the cutoff value, the meter will display zero. Selecting either square root or programmable exponent will set the cutoff value to 0. Program the cutoff value to 0 to disable.
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Programmable Exponent Linearization (Prog.E)

The programmable exponent can be used to linearize the signal from level transmitters in open-channel flow applications using weirs and flumes.
The PD6720, in combination with an ultrasonic level transmitter, makes for an economical way to measure and display open channel flow rate and total in most weirs and flumes. A guide such as the ISCO Open Channel Flow Measurement Handbook can provide the user with all the information needed: the exponent used in the flow equation for the desired flow units and the flow rate for any given head height.
For example, to display the open channel flow rate from a 3" Parshall flume, the ISCO handbook advises the exponent is 1.547 and at the maximum head height of 3.0 feet, the flow rate is 3.508 MGD.
3" Parshall Flume Discharge Table
Formula: CFS = 0.9920 H
1.547
GPM = 445.2 H
1.547
MGD = 0.6411 H
1.547
Where: H = Head in feet
Table 12-3
Head (Feet)
CFS
GPM
MGD
3.00
5.428
2436
3.508
ISCO Open Channel Flow Measurement Handbook, 3rd edition
With this information the PD6720 should be programmed in the following fashion. This setup assumes the level transmitter is programmed to output 20 mA at the maximum head height of 1.10 feet; but any mA value at a head height with a known flow rate may be used.
Function
Desired
Programming
Open Channel Flow
3" Parshall flume
Set Programmable Exponent to
1.547
Flow Rate
Millions of Gallons per Day (MGD)
Set 4 mA = 0 20 mA = 3.508 Time base = Day
Total
Millions of Gallons
Set Totalizer Conversion Factor = 1 (password protect “total” to
avoid accidental reset)
Non­Resettable Grand Total
Program meter so grand total can never be reset
Set non-resettable grand total password
Display
Display Flow Rate, Total, and Grand Total
Set upper display for Grand Total and lower display to toggle between rate and total.
Input Signal Filter (FILTER)
The noise filter is available for unusually noisy signals that cause an unstable process variable display. The noise filter averages the input signal over a certain period. The filter level can be set to low (LO), medium (med), high (HI), or off (OFF). The higher the filter setting, the longer the averaging time and so the longer the display may take to find its final value. The filter contains a noise filter bypass feature so that while small variations in the signal will be filtered out, large, abrupt changes to the input signal are displayed immediately.

Internal Calibration (ICAL)

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 traceable to NIST standards.
The internal calibration allows the user to scale the meter without applying a signal. The use of a calibrated signal source is necessary to perform the internal calibration of the meter. Check calibration of the meter at least every 12 months.
Notes: The signal source must have a full-scale accuracy of 0.002% or better between 4 and 20 mA in order to maintain the specified accuracy of the meter. Allow the meter to warm up for at least 15 minutes before performing the internal calibration procedure.
The Internal calibration menu is part of the Advanced features menu. Press and hold the MENU button for 5 seconds to enter the Advanced features menu. Press the Up arrow button to scroll to the Internal Calibration menu (ICAL) and press Enter. The meter displays 4.000 mA. Apply a 4.000 mA signal and press Enter. The display flashes for a moment while the meter is accepting the signal. After the signal is accepted, the meter displays 20.000 mA. Apply a 20.000 mA signal and press Enter. The display flashes for a moment while the meter is accepting the signal.
Error Message (SPAN ERROR)
An error message indicates that the calibration process was not successful. After the error message is displayed, the meter will revert to input 2 calibration settings. The error message might be caused by inadvertently leaving the signal at the previous level or not maintaining the minimum span. Press the Menu button to cancel the current calibration process if necessary.
Information (INFO)
The Internal calibration menu is part of the Advanced features menu. It shows software identification number and version number. To determine the software version of a meter: Go to the Information menu (INFO) and press Enter button. Continue pressing Enter to scroll through the software release number and software version. Following the information display, the meter will exit the Advanced features menu and return to run mode.
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Operation

Front Panel Buttons Operation

Button Symbol
Description
Press to enter or exit Programming Mode or exit Max/Min readings
Press to reset Max/Min readings
Press to display Max/Min readings alternately
Press to display Max or Min reading indefinitely while displaying Max or Min

Maximum & Minimum Readings (MAXIMUM & MINIMUM)

The maximum and minimum (peak & valley) readings reached by the process are stored in the meter since the last reset or power-up. The meter shows MAXIMUM or MINIMUM to differentiate between run mode and max/min display. Press Enter to remain in Max/Min display mode. If Enter is not pressed, the Max/Min display readings will time out after ten seconds. The meter will return to display the actual reading.

Reset Meter to Factory Defaults

When the parameters have been changed in a way that is difficult to determine what’s happening, it might be better to start the setup process from the factory defaults.
Instructions to load factory defaults: Enter the Advanced features menu. Press and hold Reset button when INFO is shown. Press Enter when RESET DFALTS? prompt is shown Note: If Enter is not pressed within three seconds, the
prompt will stop flashing return to showing INFO.

Factory Defaults & User Settings

The following table shows the factory setting for most of the programmable parameters on the meter. Next to the factory setting, the user may record the new setting for the particular application.
Model: ____________________________________ S/N: ______________________________________ Date: _____________________________________
Parameter
Display
Default Setting
User
Setting
Programming
PROGRAM
Scale
Input 1
INPt1
4.000 mA
Display 1
Dspl1
4.000
Input 2
INPt2
20.00 mA
Display 2
Dspl2
20.000
Decimal point rate
Dd.ddd
3 places
Decimal point total
Dddddd.dd
2 places
Tag
tag
Off
Time Base
tbase
Minute
Conversion Factor
TotCF
1.0000
Total Reset Function
T rst
Manual ­Enabled
Password
PASSWRD
00000 (unlocked)
Programming
PROGRAM
Scale
Advanced Features
Output
OUTPUT
Off
Function
FUNCTN
Linear
Cutoff
CUTOFF
0 (disabled)
Filter
FILTER
Low
MENU
RESET
DISPLAY
ENTER
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Troubleshooting

Due to the many features and functions of the meter, it’s possible that the setup of the meter does not agree with what an operator expects to see. If the meter is not working as expected, refer to the Diagnostics menu and consult the recommendations described below.

Troubleshooting Tips

Symptom
Check/Action
No display or faint display
Check input signal connections. Perform hard reset by shorting S+ and S- terminals.
Rate display unsteady
Increase filter setting in Advanced menu.
Meter displays error message during calibration (Span eRROR)
Check signal connections. Verify minimum input span requirements.
Meter flashes 99999 or -9999
Check input signal is within scaled range of 99999 and -9999.
Display stuck displaying MAXIMUM or MINIMUM
Press Menu to exit Max/Min display readings.
Display response is too slow
Check filter setting to see if it can be lowered to LO or OFF.
If the display locks up or the meter does not respond at all
Perform hard reset by shorting S+ and S- terminals.
Backlight does not appear.
Backlight is intended for viewing assistance in dim lighting conditions. It may not be noticeable under good lighting conditions.
Check connections are as shown in Figure 5. Connections with
Loop-Powered Backlight or Figure 6. Connections with Externally­Powered Backlight on page 9.
SafeTouch buttons do not respond
Service menu was selected, or mechanical button was pushed. The SafeTouch buttons will be re-enabled automatically 60 seconds after the last button push.
If slide switch on connector board is in Lock position, switch to Unlock.
Sunlight can interfere with the sensors. It is recommended to shield the window from sunlight while operating the buttons by standing so as to block direct sunlight. Other symptoms not described above
Call Technical Support for assistance.
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Quick User Interface Reference

Pushbutton
Function
MENU
Go to programming mode or leave programming. Hold for 5 seconds to enter Advanced Features menu directly.
RIGHT
Arrow
Move to next digit. Go to previous menu or alphanumeric character selection. Reset max or min while displayed.
UP
Arrow
Move to next selection or increment digit. Cycle through maximum, minimum, and mA display mode.
ENTER
Accept selection/value and move to next selection. Acknowledge alarms.
Max/Min Mode
While in Run Mode, pressing Up Arrow will initiate MAX/MIN Mode. Up Arrow toggles between MAX & MIN displays, and Right Arrow resets the MAX/MIN to the current value. Press Menu or wait 10 seconds to return to Run Mode. Pressing Enter/Ack will disable the 10 second timeout and continuously display Max or Min.
To enter the Advanced Features Menu, hold the Menu button for 5 seconds.
*Access by holding Right/Reset for 3 seconds
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PRECISION DIGITAL CORPORATION
233 South Street • Hopkinton MA 01748 USA Tel (800) 343-1001 • Fax (508) 655-8990
www.predig.com
LIM6720_C
SFT049 Ver 1.200 & up
07/20
Contact Precision Digital
Technical Support
Call: (800) 610-5239 or (508) 655-7300 Fax: (508) 655-8990 Email: [email protected]
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