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Dr Douglas Carter talks about his latest creation: the BPLM Super Spitfire

Douglas, so what is a BPLM and how did the need for a ‘Super’ one arise?

The Super Spitfire was a natural progression from the Spitfire BPLM (broadband power line modem). The development of the Spitfire BPLM was focused on creating a reliable network connection over single sections of mining cable up to about 350 to 500 metres long. We also had to develop specialised couplers for the shearer and (continuous) miner applications to launch the modem signal into the mining cables. For these applications, customers are able to get any kind of data, such as machine status and live video, from mobile machines onto the mine’s optical fibre network. After this success, some customers started asking whether it was possible to send the data further over trailing cables. We’re in the process of field trialling the Super Spitfire and so far it’s working well.

So how does the Super Spitfire actually work?

The Super Spitfire BPLM is basically a repeater for the modem signals. Because mining cables were never meant to carry these kinds of signals, there is a limit to how far a modem signal can go in a section of cable. However, you can double the transmission distance by putting two cable sections in series with a repeater in the middle. The modems at the two ends are still standard Spitfire BPLMs with standard couplers. The typical case is for a BPLM link between a miner and substation, with the signal being repeated at the DCB.
Ordinarily, you’d need two couplers at the repeater – one coupler to feed each of the cable sections. The Super Spitfire has been cunningly designed to need only a single, standard coupler, so this should really help with installation.

What increase in range can be expected and under what conditions?

Because this is a repeater type device, in theory you can keep repeating over cable sections as far as you like. The basic requirement is that the Spitfire modems must be able to create a link over each individual cable section. If that’s OK, then the repeater functionality takes care of sending the data through each link.
You need an explosion protected enclosure to put each Spitfire and Super Spitfire in. We can take advantage of the enclosures that already exist to house protection relays.

Can it be retrofitted to existing spitfire systems in underground mine sites?

Sure. For example, it’d be pretty simple to extend your miner-to-DCB link up to the substation. In the DCB, just swap the Spitfire for a Super Spitfire – it has the same mounting footprint and supply connection, and you can keep the same coupler that’s already there. The Spitfire needs a simple configuration change and moves to the substation with a new coupler.

Are there any additional benefits other than the increase in range?

As well as being a repeater, the Super Spitfire also gives you access to connect network equipment. In the example of a Super Spitfire installed in a DCB, any network-enabled gear here can be linked into the mine network – VoIP phones, protection relays and so on.
I’d probably also mention that a standard feature of our Spitfire BPLMs and coupler system is that you can easily set up a power line network that will work across multiple mobile machines. We couple the modem signal into the main bus bars in the DCB, so all the outlets are network enabled. Connected equipment can be added to the network simply by installing a Spitfire BPLM into it. You can get live data from a second miner, or a fan – or even a fish tank if you wanted to!

Douglas, thank you for the summary of this outstanding new advance in broadband power-line modem technology. If you have any questions you would like to ask Douglas about the new Super Spitfire BPLM, can be reached by email or by calling 02 9899 6857.