The Loop Leader PD6620 is a loop-powered, 1/8 DIN flow rate/totalizer designed for demanding process control applications. The four front panel buttons make setup and programming of the meter simple and intuitive. A dual-line display featuring five digits on the top line and eight digits on the bottom line, preprogrammed engineering units, and optional bargraph display (PD6624) provide a clear and attractive presentation of the process. The units of measure can be changed as needed (e.g. gallons/second to liters/second) without the need to re-scale the meter.
The dual-line display can be customized by the user to operate in such a way as to satisfy a specific application. Typically, the top line is used for the rate while the bottom line is used for the total, grand total, or engineering units. Three programmable function keys and a digital input come standard and allow the meter to be customized for use in specialized applications.
All models come equipped with two open collector outputs and are available with two solid state relays and a 4-20 mA analog output. These outputs can be programmed for alarm indication, signal retransmission via pulse or analog signal, pump control, and a number of other useful features.
The fact that this meter is loop-powered means that there is no need to run additional, costly power lines; the meter gets all of the power it needs from the 4-20 mA loop. The Loop Leader loop-powered rate/totalizer is built in a shallow-depth case with a IP65 front and features loop-powered backlighting and a wide -40 to 167°F (-40 to 75°C) operating temperature range. It doesn't matter if it's indoors or outdoors, in bright sunlight or a dimly lit plant, or in an area that is wet, dirty, hot, or cold, the Loop Leader can go just about anywhere.
- Loop-Powered Backlight with Red Backlight for Alarm Conditions
- Loop-Powered Rate/Totalizer
- Display rate & total simultaneously
- Total display includes commas for more intuitive readings
- 1.5 Volt Drop (4.5 Volt Drop w/ Backlight)
- IP65 Front
- -40 to 167°F (-40 to 75°C) Operating Temperature Range
- Five Digit Top Line
- Alphanumeric tag names
- Total, Grand Total, or Non-Resettable Grand Total
- Up to 13-digit total & grand total
- Dual Line Display
- 1/8 DIN Shallow Depth Case
- Optional Loop-Powered Solid State Relays
- Optional 4-20 mA Analog Output
- Open Collector Output Standard
- Optional Bargraph Display (PD6624)
- Batch control relay operation
- Timer functions for open collectors and relays
- Relay runtime and cycle count
- Multi-Point Linearization, Square Root, and Programmable Exponent Input Conditioning Functions
- Enter initial total & grand total count
The Loop Leader's display provides multiple ways to help users understand and keep track of their processes. The most obvious is the dual line which typically allows the user to display both flow rate and total at the same time. There is also a bargraph that includes a numeric value of the percentage the bargraph represents. Finally, to alert users to an alarm condition, the display can turn red and flash an alarm message.
Display Flow Rate & Total at Same Time
One of the key features of the Loop Leader Flow Rate/Totalizers is their ability to display flow rate and total at the same time. In addition, the meter can toggle between the rate and total and their corresponding units.
Toggle Flow Rate and Rate Units on Top,
Toggle Total Flow and Total Units on Bottom
Wide Variety of Display Capabilities
In addition to the most common setup of flow rate on the top line and flow total on the bottom line, these meters can be set up for a variety of display configurations.
Display Flow Rate and Toggle Between Units & Tag
The following table shows the items that can be displayed on the Top and Bottom lines:
|Top Line Can Display:|
|Off (Blank)||Preset batch value|
|Rate and its units alternating||Timers OC and relays|
|Total and its units alternating||Max|
|Tag||Min & Max|
|Bottom Line Can Display:|
|Off (Blank)||Units for value on top line|
|Total (with units or tag alternating)||Tag|
|Total, its units, and the rate and units alternating||Preset batch value|
|Grand total (with units or tag alternating)||Tag and rate units alternating|
|Grand total, units, and rate units alternating||Tag and total units alternating|
|Rate (with units or tag alternating)||Rate's percentage of max scale|
|Rate and the total's units alternating||mA input value|
|Rate or total units||mA output value|
Commas on 8-Digit Totalizer for Easy Reading
It may seem like a simple thing, but adding commas to an eight-digit number makes it easier to read:
Bargraph Provides Quick Understanding
To help users get a quick understanding of where their process is at, certain Loop Leader models are available with a 20-segment bargraph. This bargraph also includes a numeric value of the percentage the bargraph represents. The bargraph can be programmed to represent either the rate or total or it can be disabled.
Bargraph Based on Total
Alarms Indicated by Flashing Red Messages
When an alarm occurs, the Loop Leader's display can be programmed to turn red and flash an alarm message along with the process variable and an alarm indicator (!). (Alarm indicator symbols are not available on bargraph models) The Loop Leader's flashing red alarm message can be activated even if no relay or open collector is connected.
Change Between Units without Needing to Re-Scale the Meter
It is possible to change the display units within the selected unit class without the need to re-scale the meter. When selecting a new unit from within the DISPLAY menu (e.g. changing from gallons (GAL) to liters (L)), the meter will automatically convert the display values to display the new unit. If entering a custom unit (CUSTM), a custom conversion factor will need to be entered.
Predefined and Custom Units
The meter has six available preprogrammed unit classes, volume, height, temperature, pressure, weight, and rate. When the desired unit class or unit of measure within a class is not available, a custom unit may be programmed by using the (CUSTOM) menu.
The max & min readings (peak & valley) reached by the process can be displayed either continuously or momentarily:
- Display momentarily by pressing the F1 key (default) or assigning to any of the other function keys or to the digital input in the User menu. Press Enter to lock/unlock max/min display.
- Display continuously by assigning either display line to max/min through the Display menu.
Any of the F1-F3 function keys (buttons) and the digital input can be programmed to reset the max & min readings.
Dual-Scale Display Feature
Users can use the Loop Leader's dual-scale feature when they want to show the same input in two different scales. For instance, an application where the Loop Leader displays the input in gallons per minute and cubic feet per minute.
Rate in GPM on Top, Rate in CFM on Bottom
Loop Leaders are available with two open collector outputs as standard and two solid state relays and 4-20 mA output as options. The open collector outputs and relays generally operate in the same manner, with the major exception being the open collectors are not available for batch control or sampling and the relays are not available with pulse features. The open collectors and relays can be controlled either automatically or manually. The alarm status (with flashing red message) will show on the display even with no output wired.
Two Open Collector Outputs
The Loop Leader is equipped with two NPN open collector outputs that may be set up for pulse outputs, alarms, timed pulses, stopwatch on/off, or disabled. Pulse outputs can be set to transmit the rate, total or grand total. Output 2 may be used to generate a quadrature output based on the other open collector output. An output test mode is also selectable to generate pulses at a constant programmable frequency. The open collectors are commonly used to generate a pulse for every user-defined amount of flow that has been generated. For instance, the Loop Leader can be programmed to generate a pulse for every 100 gallons of flow.
Two Optional Solid State Relays
The meter is optionally equipped with two solid state relays that may be set up for alarms, timer, stopwatch on/off, sample or batch control. The relays are rated at 250 VAC/DC @ 1 A for resistive loads and 75 VA @ 0.6 A, 250 VAC/DC max (Safe Area only) for inductive loads. Alarms are available based on the rate, total, grand total, or digital input.
A relay set to sample will trigger when the total or grand total value has incremented by a programmed amount. The relay can be programmed to stay on for a specified amount of time. For example: if a relay is set to sample the total with a COUNT of 1,000 and a TIME of 10 seconds, the relay will energize for 10 seconds each time the total increments by 1,000 (e.g. 1000, 2000, 3000).
Optional Isolated 4-20 mA Output
The isolated analog output signal can be configured to represent the rate, total or to retransmit the 4-20 mA signal input without the need to scale the output. While the output is nominally 4-20 mA, the signal will accurately accommodate under- and over-ranges from 1 to 23 mA. The output can be reverse scaled such that the meter's high calibration value outputs 4 mA and the meter's low calibration outputs 20 mA.
Resetting the Open Collectors and Relays
The open collectors and relays (alarms) may be programmed to reset in the following ways:
- Automatic (AUTO): Alarm will reset automatically once the alarm condition has cleared.
- Automatic/Manual (AUTO.MAN): Alarm will reset automatically once the alarm condition has cleared but can also be reset using the Enter button (or whichever function key is set to acknowledge) at any time.
- Latching (LATCH): Alarm must be reset manually and can be done so at any time. Press the Enter (ACK) button at any time to clear the alarm.
- Latching with Reset after Cleared (L-CLEAR): Alarm must be reset manually and can only be done so after the alarm condition has cleared. Press the Enter (ACK) button after the alarm condition has cleared to reset the alarm.
Loop Leader flow rate/totalizers can be programmed for a wide variety of totalizer applications. They can display total, grand total, or non-resettable grand total; the rate can be displayed with a time base of seconds, minutes, hours or days. The user can program a totalizer conversion factor, a non-resettable grand total, password protection, and several total reset methods.
8-Digit Total & Grand Total Display, Up to 13 Digits Using Both Lines
The Loop Leader flow rate/totalizer can be programmed to show eight full digits of total on the bottom display or 13 digits of total using both the top and bottom displays. In both cases, the display can be programmed to include commas to make it easier to read the very large numbers; e.g. 44,987,356
In 13-digit mode, the bottom line shows the least significant digits and the top line shows the most significant digits. The meter is not capable of displaying commas on the top line, so this number is actually 1,211,230,379. The comas can be removed from bottom if desired. See sample on bottom, right.
Totalizer Conversion Factor & Multiplier
The user can enter a totalizer conversion factor that allows the meter to display total in different units than the rate. For instance, a customer could measure flow rate in gallons per minute and total in hundredths of acre-feet. A multiplier may be selected to automatically display the value in kGAL, MGAL, etc.
Totalizer Password Protection
The total and grand total can be password protected so they can be reset only by authorized personnel.
Non-Resettable Grand Total
The user can set up the grand total to be non-resettable by selecting YES for PERMLOCK in the Advanced - Grand Total - Reset menu. Once this is done, the grand total can never be reset.
Remote Total Reset
The total can be reset via an external contact closure on the digital input.
Front Panel Total Reset
The three front panel function keys can be programmed to reset the total and grand total. This makes it possible for the user to reset either the total or the grand total by pressing the appropriate function key. Of course, if the total or grand total is password protected, they will not reset when the function key is pressed unless the password is entered.
The user may program the meter for a low-flow cutoff such that the meter displays zero below this point, regardless of the input value.
The Loop Leader's two relays can be set up to alarm when the total reaches a user-defined set point. A variety of reset modes are available and the user can also program time delays and fail-safe operation.