VELTRON DPT-Plus

Product Type: Differential & Multivariable Transmitter
Technology Type: Ultra-low range Density Compensated Transmitter with Auto Zero

Get ultra-low flow accuracy, direct mass flow measurement, and reliable airflow measurement in challenging applications over time with auto zeroing capability.

The VELTRON DPT-plus transmitter is furnished with an automatic zeroing circuit capable of electronically adjusting the transmitter zero at predetermined time intervals while simultaneously holding the transmitter output signal. The automatic zeroing circuit eliminates all output signal drift due to thermal, electronic or mechanical effects, as well as the need for initial or periodic transmitter zeroing. For transmitters operating in a moderately steady temperature location (thus no thermally induced span drift), this automatic zeroing function essentially produces a “self-calibrating” transmitter.

High accuracy at very low flows
Direct mass flow measurement
Automatic zeroing to avoid offset drifts

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Features and Benefits:

Accuracy. The VELTRON DPT-plus is designed to maintain an accuracy of 0.1% of Natural Span. For a span of 0 to 0.05IN w.c., this accuracy is equivalent to an output accuracy of ±0.00005 IN w.c. differential pressure or ±0.90 FPM velocity.
Microprocessor Based Functionality. The VELTRON DPT-plus on-board microprocessor performs the functions of operating parameter selection, transmitter configuration, input/output and display signal scaling, and transducer calibration. Imbedded software performs span, flow, and 3-point “K” factor calculations. Input to the microprocessor is via pushbuttons.
Electronic Respanning. The VELTRON DPT-plus operating span can be electronically selected anywhere between the Natural Span and 40% of Natural Span, without having to perform recalibration involving an external pressure source.
Air Density Correction. The VELTRON DPT-plus can accept a process temperature input to perform density correction to volumetric or mass flow. Temperature input is a 4-20mA signal from a remote temperature transmitter; nonlinear temperature inputs can be linearized by the microprocessor. Temperature sensor type is software selectable from the following choices: Thermocouple types E, T, J, and K; or Platinum RTD.
High Turndown Ratio Operation. The VELTRON DPT-plus, 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).
Continuous Display of Process. The VELTRON DPT-plus comes equipped with a multi-line, backlit, graphical LCD for use during transmitter configuration and calibration, and to display multiple measured processes in engineering units. The LCD provides up to three lines capable of simultaneously displaying the measured process variables.
Primary Signal Noise Filter. To eliminate background noise and pulsations from the flow signal, the VELTRON DPT-plus has a user selectable low pass digital filter.
AUTO-purge Management (optional). For “dirty air” applications requiring the use of an Air Monitor AUTO-purge system, the VELTRON DPT-plus provides the capabilities of establishing purge frequency and duration while giving the user a choice of either internally timed cycle frequency or externally triggered purge initiation. During the purge cycle all transmitter outputs are maintained at their last value prior to the start of the purge cycle.
Hazardous Locations.The VELTRON DPT-plus is Factory Mutual approved for the following:
Explosion Proof: Class 1, Division 1, Groups B, C, D.

Dust Ignition Proof: Class II, III, Division 1, Groups E, F, G.

Suitable for indoor and outdoor NEMA Type 4X hazardous locations.
Enclosure. The VELTRON DPT-plus is packaged in a NEMA 4X enclosure with standard industrial process connections.
Auto Zero. Automatic zeroing circuit will re-zero the transmitter to within 0.1% of its operating span; for a transmitter with a 0.02 IN w.c. operating span, this represents a zeroing capability within 0.00002 IN w.c. To permit manual calibration of the VELTRON DPT-plus, an electronic switch is provided to permit manual positioning of the zeroing valve.

SPECIFICATIONS

PERFORMANCE SPECIFICATIONS
Ranges:	Natural Spans 0 to 25.00 IN w.c. 0 to 10.00 IN w.c. 0 to 5.00 IN w.c. 0 to 2.00 IN w.c. 0 to 1.00 IN w.c. 0 to 0.50 IN w.c. 0 to 0.25 IN w.c. 0 to 0.10 IN w.c. 0 to 0.05 IN w.c.	Bi-Polar Natural Spans -10.00 to 10.00 IN w.c. -5.00 to 5.00 IN w.c. -2.00 to 2.00 IN w.c. -1.00 to 3.00 IN w.c. -0.50 to 0.50 IN w.c. -0.25 to 0.25 IN w.c. -0.10 to 0.10 IN w.c. -0.05 to 0.05 IN w.c.
Accuracy:	0.1% of Natural Span, including non-linearity, hysteresis, deadband, and non-repeatability.
Span Rangeability:	The calibrated span can be down ranged to 40% of the Natural Span.
Stability:	±0.5% of Natural Span for six months.
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OPERATING SPECIFICATIONS
Temperature Effect:	Zero. None; corrected by AUTO-zero. Span. 0.015% of Natural Span/ºF.
Mounting Position Effect:	None; corrected through transmitter manual 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 2.0 to 250.0 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. +32 to 140ºF Operating.
Humidity Limits:	0-95% RH, non-condensing.
Display:	A backlit, graphical LCD providing three lines of data display. Also used for programming.
Analog Inputs:	Differential pressure (high and low), and 4-20mA, 2-wire, internally or externally loop powered temperature signal.
Analog Outputs:	Dual 4-20mA outputs, individually configurable as internally powered/non-isolated, or externally powered/isolated.
Digital Inputs:	Digital contacts for AUTO-purge external start.
Digital Outputs:	Dual Form A dry contacts rated for 3 amps at 24VAC/VDC for optional HI/LO alarm; or dual Form A dry contacts for AUTO-purge activation and acknowledgement.
Temperature Compensation Selection:	Pushbutton selection of linearized or non-linear temperature transmitter input for the following temperature sensing types.
	Type E	E -50 to 1750ºF	-50 to 950ºF
	Type T	-50 to 750ºF	-50 to 400ºF
	Type J	-50 to 2000ºF	-50 to 1090ºF
	Type K	-50 to 2000ºF	-50 to 1090ºF
	RTD	-50 to 1500ºF	-50 to 815ºF
Power Supply:	Standard 24VAC (20-28VAC) or 24VDC (20-40VDC). Optional 120VAC (100-132VAC), via external transformer.
Power Consumption:	Standard: 18VA at 24VAC; 13VA at 24VDC; 36VA at 120VAC. With AUTO-purge Management: 54VA at 24VAC; 48VA at 24VDC; 108VA at 120VAC.
Circuit Protection:	Power input is fused and reverse polarity protected.
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PHYSICAL SPECIFICATIONS
Enclosure:	NEMA Type 4X.
Process Connections:	Industry standard 1/4″-NPT ports on 2-1/8″ centers on flanges. 1/2″ -NPT ports on bottom of base.
Electrical Connections:	Dual 3/4″ conduit connections. Terminal strip for field wiring and test points. External terminal strip with plug-in connections.
Electrical Enclosure:	NEMA Type 4X aluminum body with Neoprene gaskets.
O-Rings:	BUNA N.
Paint:	Polyerethane with epoxy primer.
Mounting:	Flat and angle mounting brackets for 2″ pipe.
Weight:	10.5 lbs.
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APPROVALS
FM Approved:	Explosion Proof: Class I, Division 1, Groups B, C, D. Dust ignition proof: Class II, Division 1, Groups E, F, G. Suitable for indoor and outdoor NEMA Type 4X hazardous locations.

Applications:

— Combustion Airflow Processes:
- — Power Boilers
- — Combination / Biomass Boilers
- — Recovery Boilers
- — CFBs
- — Fired Heaters
- — Kilns (Lime, Ceramic, Cement)
- — Digesters
- — Thermal Oxidizers
— Dirty Airflow processes:
- — Pneumatic Conveyors
- — Primary Air for Pulverized Coal
- — CNCG & HVLC
- — Cement
— Clean Airflow Processes:
- — Aeration to Digesters

Best in Class Value Proposition:

Industry leading accuracy for airflow measurement.
Shortest straight run requirements in the industry.
Non-uniform flow profile problem solved: highest density of sensing point + patented measurement technology = excellent airflow measurement accuracy.
Dirty applications are no problem with AUTO-purge III feature.
Excellent long-term stability, repeatability, and unmatched accuracy when used with Air Monitor’s family of flow computers featuring AUTO-zero circuitry.
Available field start up services.