Rosemount TankRadar Rex RDU40 Display Unit

Rosemount Tankradar Rex Tank RDU40 Display Unit

The Rosemount TankRadar Rex RDU40 Display Unit (originally developed under Saab Rosemount Marine Electronics) is a dedicated, field-mounted, intrinsically safe remote digital indicator designed specifically for custody-transfer and process-level storage tanks fitted with the Rosemount TankRadar Rex Radar Tank Gauge (RTG 3900 series).

The RDU40 provides operators with real-time level, ullage, volume, average temperature, and gauge status data directly at the tank side or tank roof. It eliminates the need to ascend towering tanks or rely exclusively on central control room displays during bunkering, cargo transfer, or inventory verification. Featuring an intrinsically safe 3-wire physical communication and power loop, the RDU40 supports multidrop master/slave installations over distances up to 100 meters (328 ft) from the primary radar gauge head.

Model Details

• Model Designation: RDU 40 (Remote Display Unit 40)
• Part Numbers (MPN): RDU40
• 9150071-921 / 9150071-XXX series
• Saab Marine Part Ref: 0214-001 / 106029E assembly standard
• Hardware Revisions: Compatible with RTG 3900 Rex processor boards running Rex System Firmware 2.0x and higher.

Compatible Gauges

• Primary Radar Gauges: Rosemount / Saab TankRadar Rex RTG 3910, RTG 3920, RTG 3930, RTG 3940, RTG 3950, RTG 3960.
• Interfacing Junction Box: TankRadar Rex Transmitter Electronics Unit (X12 “Ex i” terminal strip).
• Cross-Family Clarification:
  • RDU 40: 3-wire intrinsically safe interface designed strictly for TankRadar Rex.
  • 2210 DU: 4-wire interface designed specifically for TankRadar Pro (includes onboard PT100 temperature conversion cards). These units are not directly interchangeable without gauge interface conversions.

Technical Specifications

Applications

• Ocean-Going Tankers & Gas Carriers: Crude oil tankers, product tankers, chemical parcel carriers, and FSO/FPSO topside inventory tanks requiring local level and ullage monitoring.
• Shore Terminal Tank Farms: Coastal bulk liquid storage, refinery off-site tankage, crude oil receipt manifolds, and finished product terminal inventory.
• Custody Transfer Skids: Local visual verification of radar custody transfer level readings prior to and during pipeline transfer or bunker bunkering.
• Corrosive & Extreme Weather Tank Roofs: Marine offshore installations exposed to high salt spray, tropical humidity, sub-zero ambient conditions, and volatile hydrocarbon vapors.

Frequently Asked Questions

Can the Rosemount RDU40 configure the TankRadar Rex radar gauge settings?

No. The RDU40 is an intrinsically safe display and monitoring unit designed for readouts and display layout customization. It does not provide radar configuration, antenna tuning, or tank geometry calibration. Gauges must be configured via Emerson Rosemount TankMaster software, the WinSetup engineering tool, or a dedicated field communicator.

What causes a checkered pattern or flashing screen on the RDU40 display?

A checkered LCD screen generally indicates a loss of data communication between the RDU40 and the RTG Rex processor board. Common causes include reversed signal polarity on the 3-wire bus, an open shield causing noise saturation, incorrect master/slave jumper assignments, or an excessive cable loop resistance exceeding the maximum 100-meter threshold.

How is the RDU40 powered? Does it require 24V DC or 110V/230V AC mains?

The RDU40 does not require external mains power. It is powered directly over the 3-wire intrinsically safe connection from terminal block X12 inside the explosion-proof housing of the TankRadar Rex gauge.

Can an RDU40 unit be used as a drop-in replacement for a Rosemount 2210 DU?

No. While they share similar housing dimensions, the RDU40 uses a 3-wire interface tailored to the TankRadar Rex, whereas the 2210 DU utilizes a 4-wire interface designed for the TankRadar Pro and includes internal temperature measurement cards. Use only the RDU40 on TankRadar Rex systems.