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Developments and Successes in Tank Gauging Solutions

Targeted at smaller Vessels, our DGTS provides an integrated solution with a central display communicating digitally via RS485 to a network of connected sensors, providing a simple to instal system with significant savings on cabling and commissioning time

We have subsequently seen installations of our DTGS completed and further expansion of the systems capabilities meaning it now provides a scalable solution for Vessels of all sizes.

At the heart of the tank gauging system is our VPM family of data acquisition and processing hardware which is now available in three basic types:

For Smaller Vessels – VPM

For vessels such as Tugs, Work boats and Yachts where typically there are 10 – 20 tanks requiring monitoring and space is limited the VPM is packaged with an integral 7” touchscreen display.  The VPM connects to Scanjet PSM’s APT1000 transmitters installed in each tank via a simple to install RS485 multi-drop network, where a single 4 core cable carries both power and communication lines to the transmitters. This 4-core cable is run between Scanjet PSM’s RFM termination modules creating a simple “backbone” to which APT1000 transmitters are connected. For installations requiring Intrinsically Safe certification a single RFM ISR safety barrier protects the entire network.

If indication is required at additional points, further VPM displays (up to 6 in total) can be added. These are interconnected via a dedicated Ethernet link and share all data meaning the contents of all tanks can be displayed at all points. These additional VPM’s can act simply as displays but may also have their own connected APT1000 transmitters. This flexibility ensures that expensive and time-consuming cabling is kept to a minimum.

Each VPM can also output tank status via a second RS485 Serial port using standard Modbus RTU protocol. This can be connected to other onboard systems, e.g., Alarm Monitoring Systems, Loading Computer.

For Larger Systems – VPM+

For larger vessels, or systems where a more comprehensive display is required, the same architecture is used to directly connect to the APT1000 transmitters and the VPM with the integral 7” touchscreen is used as signal acquisition and processing unit, as well as providing a local display.

Additional firmware introduces the capability of adding larger remote display(s). As many remote displays as required can be added, all connected via an Ethernet network back to the VPM. The remote display hardware can be any type of device with an ethernet connection and capable of running a web browser. Typically, this will be a 19 to 24” touchscreen display with a small Hub to handle communications.

The remote displays are not reliant on Windows operating system providing a more cost effective and reliable approach to using a PC based solution.

Adding to the flexibility and expandability of this solution is a range of signal input modules. These modules allow measurement instruments other than the APT1000 level transmitter to be connected to the system. These modules have embedded intelligence and process the signals from connected instruments, translating all information into Modbus RTU format.

Modules include

  • 12 channel Radar transmitter Cargo level Inputs
  • 12 channel 4-20mA transmitter inputs
  • 8 channel RS485 input module where each RS485 input can connect to a further module that accepts up to 14 PT1000 temperature sensors.

All input modules incorporate Zener Safety Barriers for Intrinsically Safe installation meaning external additional Barriers are not needed.

Fully Featured Systems – VPMS

Where the system requires a significant number of input points, for example a Tanker where all ballast tanks, service tanks, cargo tanks, cargo temperature cargo overpressure, vapour lines, cargo lines, draught, are to be monitored then a more comprehensive display is needed for clarity.

In this case the central module provides the same acquisition and processing function but in a repackaged format with additional RS485 communication ports and dual Ethernet connection as well as integral configurable status and alarm relays. It has the same flexible choice of input cards and remote displays as the VPM+ providing infinite expansion of the system.

The second Ethernet port also allows for external connection to other systems and / or via the Internet, and the additional RS485 ports allow for onboard connection to multiple external systems such as Loading Computers, VDR, AMS.

With larger systems each project is considered based on its overall needs and will be packaged accordingly.

Successes to date

So far in 2021 VPM systems have been supplied for several Tug projects and the first of 5 Systems for Naval Corvettes built in Navantia, Spain has been commissioned.

Multiple VPM+ systems have been delivered for refit applications as diverse as Fishing Vessels, Ferries, and Naval Tankers.

The VPMS solution will form the basis of the forthcoming Scanjet Connect system which will require a full suite of Marine certification and approvals. All independent EMC and Environmental tests have been concluded and recently DNV successfully conducted witnessed factory testing of the functional aspects of the system for Type Approval Certification for which we now await formal approval. This approval will include MED certification as required for Passenger Vessel SRTP requirements.

With many further proposals under discussion Scanjet PSM’s new solutions are proving to be precisely what the market is looking for, both for retrofit and newbuild projects.

If you have a requirement, to find out more, please download our VPM Systems Brochure.


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