Air Monitor VELTRON DPT 2500-plus User manual

Installation, Operation,
and Maintenance Manual
VELTRON DPT 2500-plus
Microprocessor Based Ultra-Low Range
Pressure & Flow "Smart" Transmitter
Version 1.0X
Installation, Operation & Maintenance
Air Monitor Corporation provides complete
technical support between the hours of
7 a.m. and 5 p.m. PST, M-F
Contact our Service Department
Toll Free: 1-800-AIRFLOW
or fax us at 1-707-526-2825
Air Monitor Corporation
116-047-20.PMD (5/5/11)
VELTRON DPT 2500-plus - IO&M Manual

VELTRON DPT 2500-plus
Air Monitor Corporation
116-047-20.PMD (5/5/11)
VELTRON DPT 2500-plus - IO&M Manual
TABLE OF CONTENTS
TABLE OF CONTENTS
INSTRUMENT WARRANTY .................................................................................................................... i
SECTION 1 – GENERAL INFORMATION
1.1 DESCRIPTION ............................................................................................................................... 1
1.2 THEORY OF OPERATION ............................................................................................................. 1
SECTION 2 – PERFORMANCE SPECIFICATIONS
2.1 TRANSMITTER .............................................................................................................................. 2
2.2 INDICATION ................................................................................................................................... 2
2.3 OUTPUTS ...................................................................................................................................... 2
2.4 POWER .......................................................................................................................................... 2
SECTION 3 – FEATURES
3.1 USER SETUP MENU ..................................................................................................................... 3
3.2 TRANSMITTER HOLD ................................................................................................................... 3
3.3 AUTOMATIC ZEROING ................................................................................................................. 3
3.4 DATA DISPLAY ............................................................................................................................... 3
3.5 HIGH TURNDOWN RATIO OPERATION ....................................................................................... 3
3.6 ENCLOSURE ................................................................................................................................. 3
3.7 MULTIPLE OPERATING POWER SELECTIONS .......................................................................... 3
SECTION 4 – INSTALLATION
4.1 RECEIVING AND INSPECTION .....................................................................................................4
4.2 LOCATION ..................................................................................................................................... 4
4.3 MOUNTING .................................................................................................................................... 5
4.4 PROCESS CONNECTIONS ........................................................................................................... 6
4.5 POWER/SIGNAL CONNECTIONS ................................................................................................ 7
4.6 OUTPUT SELECTION ................................................................................................................... 7
4.7 DISPLAY CONTRAST ADJUSTMENT ........................................................................................... 7
SECTION 5 – OPERATION
5.1 INTRODUCTION ............................................................................................................................ 8
5.2 START-UP ...................................................................................................................................... 8
5.3 NORMAL OPERATION .................................................................................................................. 9
5.4 CONFIGURATION .......................................................................................................................... 9
5.5 PUSHBUTTON DEFINITION ........................................................................................................10
5.6 CONFIGURATION PROGRAMMING ...................................................................................... 11-12
5.7 TRANSMITTER SCALING & CONFIGURATION .................................................................... 13-17
5.8 LOW PASS FILTER ...................................................................................................................... 18
5.9 AUTO-zero CONFIGURATION ..................................................................................................... 19
5.10 TRANSDUCER SPAN SELECTION ............................................................................................. 20
5.11 TRANSMITTER INPUT CALIBRATION ........................................................................................ 21
5.12 TRANSMITTER OUTPUT CALIBRATION .................................................................................... 21

TABLE OF CONTENTS
SECTION 6 – CALIBRATION
6.1 REQUIRED EQUIPMENT ............................................................................................................ 22
6.2 PREPARATION ............................................................................................................................ 22
6.3 TRANSMITTER INPUT CALIBRATION ................................................................................... 23-25
6.4 TRANSMITTER OUTPUT CALIBRATION ............................................................................... 26-27
SECTION 7 – MAINTENANCE ............................................................................................................. 28
SECTION 8 – TROUBLESHOOTING ................................................................................................... 29
SECTION 9 – PARTS LIST ................................................................................................................... 30
SECTION 10 – CUSTOMER SERVICE................................................................................................. 31
TABLE OF CONTENTS
VELTRON DPT 2500-plus
Air Monitor Corporation
116-047-20.PMD (5/5/11)
VELTRON DPT 2500-plus - IO&M Manual

VELTRON DPT 2500-plus
Air Monitor Corporation
116-047-20.PMD (5/5/11)
VELTRON DPT 2500-plus - IO&M Manual
i
INSTRUMENT WARRANTY
NOTICE OF PROPRIETARY RIGHTS
This document contains confidential technical data, including
trade secrets and propriet ary information which are the sole
property of Air Monitor Corporation. The use of said data is
solely limited to use as specified herein. Any other use is strictly
prohibited without the prior written consent of Air Monitor
Corporation.
INSTRUMENT WARRANTY
Air Monitor Corporation (hereinafter referred to as “Seller”)
warrants that at the time of shipment, products sold
pursuant to this contract will be free from defects in
materials and workmanship, and will conform to the
specifications furnished or approved in writing by Seller.
No warranty is given that delivered products will conform
to catalog sheets, data sheets, and the like, which are
subject to change without notice.
Seller will repair or replace, at its option, any products
listed under this warranty which is returned freight prepaid
to Seller within the earlier of three (3) years after start-up
or thirty-nine (39) months after shipment that, upon test
and examination, proves defective within the terms of
this warranty. The warranty period for any item repaired
or replaced shall be for the time remaining on the warranty
period of the original components. Purchaser shall notify
Seller in writing of such defect within sixty (60) days of
discovery of the defect.
This warranty does not extend to any product sold by
Seller which has been the subject of misuse, neglect,
accident, damage or malfunction caused by
interconnection with equipment manufactured by others,
improper installation or storage, or used in violation of
instructions furnished by Seller, nor does it extend to any
product which has been repaired or altered by persons
not expressly approved by Seller. Nor does Seller warrant
equipment against normal deterioration due to
environment; nor items such as lamps, glass, and similar
items subject to wear or burnout through usage.
Adjustments for items or equipment not manufactured
by Seller shall be made to the extent of any warranty of
the manufacturer or supplier thereof.
Seller shall not be liable for any special or consequential
damages or for loss of damage, directly or indirectly
arising from the use of the products. Seller's warranty
shall be limited to replacement of defective equipment
and shall not include field removal and installation
expenses.
The warranty set forth above is in lieu of all other
warranties either express or implied and constitutes the
full extent of Air Monitor Corporation's liability to the
customer, or any other party for breach of warranty.
THERE ARE NO EXPRESS WARRANTIES EXCEPT AS
SET FORTH HEREIN AND THERE ARE NO IMPLIED
WARRANTIES OF MERCHANTABILITY OF FITNESS
FOR ANY PARTICULAR PURPOSE, WHICH ARE
PARTICULARLY DISCLAIMED.

VELTRON DPT 2500-plus
Air Monitor Corporation
116-047-20.PMD (5/5/11)
VELTRON DPT 2500-plus - IO&M Manual
1
SECTION 1 – GENERAL INFORMATION
1 – GENERAL INFORMATION
1.1 – DESCRIPTION
The VELTRON DPT 2500-plus is an ultra-low differential pressure "smart" transmitter designed to convert the low
magnitude pressure signals generated by airflow stations and probes, or static pressure sensors into an output signal
(4-20mA, 0-5VDC or 0-10VDC) linear to pressure or flow.
Each VELTRON DPT 2500- plus is equipped with numerous standard features: A multi-line LCD used during
configuration/calibration and for display of process; AUTO-zero for elimination of transmitter zero error; user selectable
primary signal noise filter, input power isolation; capability of 10:1 flow or 100:1 pressure turndown; and an optional
NEMA 12 enclosure (NEMA 1 is standard).
1.2 – THEORY OF OPERATION
High and low pressure signals generated by airflow stations and probes, or static pressure sensors act upon opposite
sides of a flexible diaphragm within the transducer. The differential between the two pressure signals displaces the
diaphragm; the magnitude of the displacement being measured creates an electrical DC output from the transducer.
After undergoing A/D conversion, the resulting digit al signal representing differential pressure or velocity pressure
can be "manipulated" within the microprocessor: square rooted for velocity or flow application; scaled for unit s of
measure and area for process output; and scaled for local data display. The built-in microprocessor runs the program
that provides the following basic functions: Timing, logic, and mathematical operations, analog input signal multiplexing,
analog input/output calibration, automatic zeroing valve operation, User Setup menu system, and display (LCD)
indication.

VELTRON DPT 2500-plus
Air Monitor Corporation
116-047-20.PMD (5/5/11)
VELTRON DPT 2500-plus - IO&M Manual
2
SECTION 2 – PERFORMANCE SPECIFICATIONS
2 – PERFORMANCE SPECIFICATIONS
2.1 – TRANSMITTER
Accuracy. 0.25% of Natural Span, including hysteresis,
deadband, non-linearity, and non-repeatability.
Type. Differential pressure, flow, and mass flow.
Ranges.Natural Spans Bi-Polar Natural Spans
0 to 25.00 IN w.c.
0 to 10.00 IN w.c. –10.00 to 10.00 IN w.c.
0 to 5.00 IN w.c. – 5.00 to 5.00 IN w.c.
0 to 2.00 IN w.c. – 2.00 to 2.00 IN w.c.
0 to 1.00 IN w.c. – 1.00 to 3.00 IN w.c.
0 to 0.50 IN w.c. – 0.50 to 0.50 IN w.c.
0 to 0.25 IN w.c. – 0.25 to 0.25 IN w.c.
0 to 0.10 IN w.c. – 0.10 to 0.10 IN w.c.
0 to 0.05 IN w.c. – 0.05 to 0.05 IN w.c.
Span Rangeability. The calibrated span can be down
ranged to 40% of the Natural Span.
Stability. ±0.5% of Natural Span for six months.
Temperature Effect.
Zero. None; corrected by AUTO-zero.
Span. 0.015% of Natural Span/ºF.
Mounting Position Effect. None; corrected through
transmitter automatic zeroing.
Span and Zero Adjustment. Digital, via internally
located pushbuttons.
Low Pass Filtration. Response time to reach 98% of
a step change is adjustable from 0.5 to 256.0
seconds.
Overpressure and Static Pressure Limit. 25 psig.
Automatic Zeroing.
Accuracy. Within 0.1% of calibrated span.
Frequency. Every 1 to 24 hours on 1 hour intervals.
Temperature Limits. –20 to 180ºF Storage; +40 to
140ºF Operating.
Humidity Limits. 0-95% RH, non-condensing.
2.2 – INDICATION
Display. A backlit, graphical LCD providing single line of
data display. Also used for programming.
2.3 – OUTPUTS
Analog Output. Single output linear to pressure, flow,
or massflow configurable via jumper to 0-5V , 0-10V, or
4-20mA.
2.4 – POWER
Power Supply. Standard 24VAC (16-30VAC) or 24VDC
(16-40VDC).
Power Consumption. Standard: 8VA at 24VAC; 6VA
at 24VDC.
Circuit Protection. Power input is isolated, fused, and
reverse polarity protected.

VELTRON DPT 2500-plus
Air Monitor Corporation
116-047-20.PMD (5/5/11)
VELTRON DPT 2500-plus - IO&M Manual
3
SECTION 3 – FEATURES
3 – FEATURES
3.1 – USER SETUP MENU
The microprocessor program contains a User Setup menu system for setting user selectable parameters. Four
pushbuttons, allow the user access to the menu for setting configuration modes and values. Refer
to the Configuration Programming (Section 5.6) instructions for operation details. Also contained in the User Setup
menu is all input and output calibration. The calibration method is completely digital and contains no analog
potentiometer adjustments which are susceptible to drift. Non-volatile memory is used for storing all setup parameters
and calibration values, and will remain unchanged after set, even when power to the unit is off.
3.2 – TRANSMITTER HOLD
Certain operations performed by the microprocessor place the unit into a Hold mode. This occurs when the User
Setup menu system is activated or when an AUTO-zero is performed. When in Hold, all Normal mode processing is
halted and the output is held at its last value prior to Hold. Normal operation is indicated by the "CPU Activated" 
(dot) in the lower left of the display blinking at a rate of four times per second. A Hold mode is indicated by the "CPU
Activated"  (dot) blinking at a rate of once per second.
3.3 – AUTOMATIC ZEROING
At periodic intervals the microprocessor will automatically execute an AUTO-zero cycle consisting of the following
sequence: The transmitter output and display signals are put on Hold; a valve is activated which disconnects the
process high pressure from the high port of the transducer and connects the process static pressure to both sides of
the transducer, creating a true zero differential pressure; after a brief stabilization period, the transducer zero offset
signal is measured and stored in memory; the valve is deactivated and after a brief period for process signal stabilization,
the Hold is released and Normal process measurement resumes. will be displayed whenever AUTO-
zero cycle is in progress.
During Normal operation, the zero offset value stored in memory is subtracted from subsequent transducer readings
until the next AUTO-zero cycle occurs and repeats the process. For calibration purposes a switch is provided which
allows the user to manually activate the zeroing valve . AUTO-zero On/Off and Interval are available and configurable
using the User Setup menu. 3.4 – DATA DISPLAY
The large integral display is a backlit graphical LCD that displays the current measured process, and is used during
configuration. 3.5 – HIGH TURNDOWN RATIO OPERATION
The VELTRON DPT 2500-plus transmitter, with its high level of accuracy and automatic zeroing circuitry, can maintain
linear output signals on applications requiring velocity turndown of 10 to 1 (equal to a velocity pressure turndown of
100 to 1). 3.6 – ENCLOSURE
The VELTRON DPT 2500-plus transmitter is packaged in a NEMA Type 1 enclosure with standard industrial process
connections. A NEMA Type 12 enclosure is optionally available.
3.7 – MULTIPLE OPERATING POWER SELECTIONS
The VELTRON DPT 2500-plus can be powered by 24VAC or 24VDC.
auto zero
X

VELTRON DPT 2500-plus
Air Monitor Corporation
116-047-20.PMD (5/5/11)
VELTRON DPT 2500-plus - IO&M Manual
4
4 – INSTALLATION
SECTION 4 – INSTALLATION
4.1 – RECEIVING AND INSPECTION
• Carefully remove the VELTRON DPT 2500-plus from the shipping container and inspect for any damage. If any
damage has occurred in transit, contact freight carrier.
• Save the shipping container for possible future use in returning the VELTRON DPT 2500-plus to the factory for
recalibration.
• Review the Factory Set-Up Information Sheet provided with the unit and verify the WO # and Serial # match those
on the VELTRON DPT 2500-plus. Verify that the configuration recorded on the Factory Set-Up Information Sheet is
correct for your application. If not, contact Air Monitor's Customer Service Department at 1-800-AIRFLOW for
further guidance.
Note: The VELTRON DPT 2500-plus has been configured and calibrated to customer specified parameters (see
"Factory Setup Information Sheet" provided with the unit), and requires no additional calibration/verification
prior to installation.
4.2 – LOCATION
• The standard version of the VELTRON DPT 2500- plus is a NEMA 1 enclosure suitable for most clean indoor
locations. If additional protection is required, mount unit in an enclosure with adequate NEMA rating.
• The industrial version of the VELTRON DPT 2500-plus is housed in a NEMA 12 enclosure (see NEMA ratings for
degree of protection).
• The ambient temperature of the selected mounting location must be between +40º to 120ºF. Consideration should
be given to units exposed to direct sunlight.
• The selected mounting location should be rigid and free of vibration.

VELTRON DPT 2500-plus
Air Monitor Corporation
116-047-20.PMD (5/5/11)
VELTRON DPT 2500-plus - IO&M Manual
5
4.3 – MOUNTING
Mounting
– Tools Required: Electric drill; #25 (0.1495") bit; screwdriver or nutdriver; and four #8-32 self-tapping machine screws.
– The VELTRON DPT 2500-plus can be mounted in any position provided it is secured using all four mounting holes.
– Reasonable consideration should be given to clearances for pressure and electrical connections.
– Once a suitable location is found, use the unit as a template to mark the centers of the four mounting holes.
– Drill four pilot holes at the marked locations. With the unit in position, install the four #8-32 screws.
Figure 4.1
SECTION 4 – INSTALLATION
plus
VELTRON DPT 2500-
VELTRON DPT 2500-plus