It may sound incredible but the Radio Data Networks FDT (Flow Detection Transducer) has now been in service for over 5-years without a single reported issue due to battery failure or moisture ingress. However, as others now struggle to get their systems to respond at 2-minute intervals many are not aware that the FDTs actually detect and report flow at an astonishing rate of 2.5-seconds, meaning that no intervention whatsoever is required in the chamber and there is no impact on the FDTs typical 10-year battery life to achieve compliance with the new Environment Agency’s 2-minute reporting requirements at Combined Sewer Overflows for EDM (Event Duration Monitoring).
In practice actual reporting rate of the FDT is set by the above ground collection/logging device, the choice of which as grown enormously since 2012. The original system and by far still the most popular, utilises a battery powered “Booster“, a small wireless repeater box attached to a lamp post to relay the status of a FDT back to telemetry or SCADA, using an Ofcom licenced data channel where it operates a simple relay contact proportional to the duration of the event.
Now in 2017, we offer a wide range of solutions that include use of the Tetra data channels, LAN and also the Iridium Satellite network permitting an FDT to be installed virtually anywhere on the planet! Data can also now be delivered in a wide variety of formats from SDS Tetra Messages, SBD satellite packets, IP packets, e-mails to files in JSON, CSV, XML and the aforementioned volt-free relay contacts.
FDT vs GSM/GPRS + Ultrasonic Combination: Typical Performance
|Parameter||FDT||GSM/GPRS + Ultrasonic Head||Notes:|
2-Minute EDM Compatible
|Yes with limitations
2 or 15-min
|The FDT reporting rate is set by the associated Booster or Gateway|
|Health Message||Yes||No||Every 4-minutes|
|Deployment Depth||4m and 10m||3m|
|Real-Time Data & Control||Yes||No||Direct Link to Pumps and valve Controls|
|Battery life||7-10 years||6-16mths|
|IP68 + 100% Potted Design for Constant Submersion||Yes||Partial|
|Field Programming||Not Required||Yes||FDT Trigger set by cable ties|
|Confined Space Entry||Not Normally Required||Yes||FDT Normally installed from the surface – no brackets required|
|Visual Verifiable Trigger Point||Yes||No||FDT is easy to align with spill channel|
|Live Drive-By Status Report to Vehicle||Yes||No|
|SIM Card Required||No||Yes|
|Communication Options||Licenced Radio
Tetra / DMR
100% Cyber Secure Internet Free Options
|No – Requires GPRS/ 3G IP Backbone||
Relay Option to existing Outstation and SCADA
The last option, that of relay contact is the most powerful of the FDT’s delivery modes. The local relay contacts aside from providing a totally cyber secure interface to telemetry and SCADA have already been used in anger to instigate a number of local mitigation strategies from switching off pumps that may be feeding the CSO to closing valves at the outlet in dry weather.
In Summary, the FDT is an ideal, high reliability, low maintenance; low TOTEX solution for 2-minute EDM with a proven track record and that has won multiple awards for its ease of use, testability and ability to integrate with existing systems. Further, as the cellular industry migrates fist to 4G and then 5G by 2021, the FDT with it SIM free operation also offers the assurance of operation well into the next decade.
Finally, existing FDT deployments can be upgraded to 2-minute reporting without the need to access the installed device as the only alteration required is the reporting rate of the above ground mounted collection device typically a “Booster”.
Radio Data Networks Limited October 2017