Honeywell Enraf Vito 768 Probe UAAN768D16801330/Z

Honeywell Enraf VITO 768 Combined Temperature & Water Bottom Probe (MPN: UAAN768D16801330/Z)

The Honeywell Enraf VITO 768 is an intrinsically safe, flexible immersion probe engineered for simultaneous multiple-element average temperature profiling and capacitive water-bottom interface measurement. Purpose-built for bulk liquid inventory and marine custody transfer applications, the model UAAN768D16801330/Z integrates into Honeywell Enraf automated tank gauging (ATG) architectures via the Model 762 VITO Interface Unit.

Housed in corrugated AISI 316L stainless steel sheathing with a PFA fluoropolymer capacitive coating, the probe continuously monitors thermal layer stratification across 9 discrete sensing elements while delivering sub-millimeter bottom-water detection to guarantee net standard volume (NSV) inventory calculations in accordance with API Chapter 7 and ISO 4268 custody-transfer guidelines.

Technical Details

Features

1. Dual-Function Process Measurement: Delivers true spot/average volumetric temperature integration along with continuous 500 mm bottom-water tracking on a single penetration flange.
2. High-Precision Element Arrays: 9 thermo-elements combined with a cold-junction Class 1/6 DIN Pt100 RTD yielding probe accuracy within ±0.1°C (±0.18°F).
3. Aggressive Media Protection: Fabricated from flexible AISI 316L stainless steel (1.4404) with virgin PFA insulation to resist sour crude, heavy residual fuels, marine distillates, and aromatic solvents.
4. Intrinsically Safe Ex ia Architecture: Certified for Zone 0 (Class I, Div 1) submerged continuous operation under ATEX, IECEx, and FM hazardous approvals.
5. Seamless ATG Network Integration: Direct multi-drop link to Honeywell Enraf 854 Series Servo, 954 Series, and 990 SmartRadar gauges via the 762 VITO HART Interface.

Compatible Transmitters & Host Gauges

• Honeywell Enraf 762 VITO Interface Unit: Models 762-P (VITO LT) and 762-T via G 1/2 internal union.
• Honeywell Enraf Servo Gauges: Models 854 ATG, 854 XTG, and 954 Series Servo Level Gauges.
• Honeywell Enraf Radar Gauges: Series 990 SmartRadar, SmartRadar FlexLine (via VITO interface module or HCU board).
• Field Communication Protocols: GPU protocol over RS-485 Enraf BPM (Bi-Phase Mark) or standard 2-wire HART multi-drop link.

Senior Marine & Instrumentation Engineer Notes:

1) Bending Radius Management: The corrugated AISI 316L sheath must never be bent sharper than a 400 mm (16-inch) radius during deployment. Kinking or pinching the sheath breaks the capillary alignment of internal thermocouple leads and induces capacitive shifts across the PFA dielectric barrier.

2) Bottom Element Zeroing: Because this model uses configuration D, the lowest element sits directly inside the probe shoe. Ensure host gauge firmware setting MJ is properly switched. If product level falls below 1 meter, the bottom element can provide spot temperatures; however, when the capacitive circuit flags a water interface, host logic must exclude this element from product average calculation to avoid skewing inventory math.

3) Ballast / Anchor Weighting: Always use the dedicated spring-loaded bottom anchor assembly or a steadying weight (typically 15 kg to 23 kg). Liquid turbulence in un-stilled tanks will whip the probe, inducing lateral stress on the top G 1/2 thread and causing signal drift.

4) Megger Testing Caution: Never perform high-voltage insulation (Megger) checks between probe flying leads and the outer shield while attached to the 762 Interface. Disconnect completely and observe intrinsic safety loop safety barriers to avoid blowing the sensitive input capacitors.

Frequently Asked Questions

What is the mechanical difference between Honeywell Enraf VITO 767 and 768?

The VITO 767 is an average-temperature-only probe equipped with 9 internal sensors. The VITO 768 is a combination (“combi”) unit integrating both the 9-element temperature array and an active capacitive water-bottom sensor inside the same flexible 316L sheath.

How does the VITO 768 calculate average temperature when the tank is partially full?

The host Enraf gauge uses liquid level measurements from the servo or radar system. It dynamically compares the surface level against individual sensor positions in the probe’s 16.8 m span and includes only fully submerged elements in the calculated average product temperature, isolating elements exposed to vapor.

What is the purpose of the 762 Interface Unit?

The probe produces analog signals from thermocouple junctions and capacitive variance from the water sensor. The 762 Interface houses the analog-to-digital processing circuitry, handles cold-junction compensation via an internal Pt100 reference, and outputs digital HART or serial data to the main tank level gauge.

Can this probe be mounted in pressurized tanks?

The VITO 768 is rated for a continuous hydrostatic working head pressure of 5.0 bar (500 kPa / 72.5 psi). It is intended for atmospheric bulk liquid tanks or low-pressure marine cargo compartments. Pressures beyond 5.0 bar will deform the corrugated sheath and compromise capacitive water readings.