mattevans Posted January 30, 2005 Share Posted January 30, 2005 I own both the Le Maitre Pro Stage Two Way and Pro Stage Six Way. I have discovered that under certain conditions, even when the batteries have been removed from the unit, the controller will fire pyros that are still connected. I feel that this is potentially dangerous and so should be brought to the attention of the manufactuers and everyone that may be using them. I do not wish to stop people from using Le Maitre's products and neither do I wish to hard Le Maitre's repuation because I really do like their products. Thank You Matt Link to comment Share on other sites More sharing options...
DSA Posted January 30, 2005 Share Posted January 30, 2005 I am far from a pyro expert - but I believe this would be normal operation, as the batteries charge up a capacitor inside the unit. It is the discharging of this capacitor when the fire button is pressed, that sends the signal to the ignitor. I may be wrong, but seem to remember that there is a capacitor in the units from when Mark was speaking at PLASA. The usual will apply in making sure that all is safe before firing etc., and because the key has to be in for a fire to happen I see it as safe myself. Why do you consider this 'potentially dangerous' - do you keep the key switched all the time? David Link to comment Share on other sites More sharing options...
Pyromark Posted January 30, 2005 Share Posted January 30, 2005 Why is this dangerous? It is true that after the batteries are dead (or removed) there is still a charge in the cap, this is because the cap is always charged and ready to go, if we wired it to short each time the key is turned off it could take upto 10 seconds (depending on battery conditions) to charge the cap Sufficiently to fire the maximum number of pyros we say. As most of us who fire pyros know, the key only gets turned immediately before firing, most of he time that is only 1-2 seconds before pushing the button. I do take your point though, And I could see a situation where an inexperienced operator would conduct a dummy firing without batteries. If this were the case the test LED would also light and (I would like to think) would ring alarm bells. I will bring the issue up with the directors and R&D dept on Monday, It might be that a warning just gets printed in the manual and on the unit Mark Link to comment Share on other sites More sharing options...
paulears Posted January 30, 2005 Share Posted January 30, 2005 What are the certain conditions? These are capacitor discharge firing units, I'm reasonably certain - so the keyswitch is the only SAFE method of preventing firing. I'm guessing, but removing the batts, then arming and pressing fire, will probably fire a pyro. Do tell? Link to comment Share on other sites More sharing options...
paulears Posted January 30, 2005 Share Posted January 30, 2005 This must be a record - 3 people typing a reply at the same time! (and thankfully, all saying the same thing) Link to comment Share on other sites More sharing options...
Pyromark Posted January 30, 2005 Share Posted January 30, 2005 Oooooh Spooky!! Link to comment Share on other sites More sharing options...
Brian Posted January 30, 2005 Share Posted January 30, 2005 I think the problem is that someone may assume that with the batteries out the unit is safe to 'play' with. We're all trained to pull the plug on any equipment before we work on it to make it safe; the problem with battery equipment is that we sometimes assume that removing the batteries will make it safe as well. Link to comment Share on other sites More sharing options...
gareth Posted January 30, 2005 Share Posted January 30, 2005 I think the problem is that someone may assume that with the batteries out the unit is safe to 'play' with. We're all trained to pull the plug on any equipment before we work on it to make it safe; the problem with battery equipment is that we sometimes assume that removing the batteries will make it safe as well.<{POST_SNAPBACK}>Very true. However, as Mark said, the illumination of the circuit continuity indicator would surely be enough to suggest to the user that there's still power somewhere in the system, and that the risk of detonation is still present. I'm not intimately familiar with the specific units in question, but I'd imagine that the arming keyswitch is 'downstream' of the battery and capacitor? So in order for an accidental firing to happen, the keyswitch would have to be consciously armed and the fire button pressed. As Mark has also said - normal practice, surely, is for the keyswitch to remain off at all times unless you're within a few seconds of the moment of firing, immediately after which the keyswitch is returned to 'safe' again? So for 'acciedntal' firing to occur under these circumstances, the keyswitch would have to be turned on, the circuit selected via the rocker switch, and the fire button depressed - three deliberate actions which are most unlikely to take place accidentally. While I can see that this particular characteristic of the unit might be a problem to an inexperienced operator who's not familiar with the system - but should such a person be operating it in the first place? Matt, you say that you've discovered that this can happen under "certain conditions" - like other people who've posted in this thread, I'd be interested to hear a bit more about what these "certain conditions" involve. Link to comment Share on other sites More sharing options...
paulears Posted January 30, 2005 Share Posted January 30, 2005 I see Matt posted the very same statement on ABTT even after we'd all commented, asking for the 'certain conditions'. (just after 8pm) At the very least Matt, this is a little rude - and duplicating posts doesn't make you popular on either site. With the knowledgeable people on this forum (ignore me, of course) I think the advice rather exonerates the manufacturer and perhaps suggests some changes that need making to the operating procedure you use. Suggesting the product could be potentially dangerous is rather unfair, unless you have specific issues in mind. Paul Link to comment Share on other sites More sharing options...
gareth Posted January 30, 2005 Share Posted January 30, 2005 I see Matt posted the very same statement on ABTT even after we'd all commented, asking for the 'certain conditions'. (just after 8pm) At the very least Matt, this is a little rude - and duplicating posts doesn't make you popular on either site.My three-year-old does that, too. If she doesn't get the answer she wants from me, she goes and asks her mum instead ... :** laughs out loud **: ;) Link to comment Share on other sites More sharing options...
DSA Posted January 30, 2005 Share Posted January 30, 2005 Whilst I agree wholeheartedly with what Paul is saying, the post is identical - and I personally feel that Matt is trying to make people aware of what he considers a 'dangerous' design. I don't agree, but obviously Matt thinks that it is. David Link to comment Share on other sites More sharing options...
Lincoln Posted January 31, 2005 Share Posted January 31, 2005 I can offer up an suggestion to what the "under certain conditions" are with regard this subject... If an operator switches "ON" the keyswitch and then decides not to fire a device/effect and as a result, returns the keyswitch to the "OFF" position and for additional safety, removes the two 9 Volt batteries... there is a "psychological assumption" that the unit is safe, even with a slow discharge resistor draining down the capacitor as Mark has explained. The "under certain conditions" that Matt is probably describing relates to an operator or other person with a key returning to the unit within a few minutes and turning "ON" the keyswitch again without any apparent energy source. I hasten to add to the debate, (before you all start questioning/replying...) as to "WHY" somebody might try and do this... however... The control system WILL fire/operate in these circumstances even if the 2 x 9 Volt batteries have not been refitted to the unit. ... It did catch us out on a job once when we were being inspected by the local authority officer to whom we were trying to spell out our safety procedures and tell him that we had added extra safety and decreased our potential risks of a accidental/premature firing by removing the batteries from the control system. Fortunately, when we did say "look - no batteries and now it is extra safe", we turned the key on, selected the effect on the first channel and pressed the button... ...We were lucky... The device on the first channel was a single medium airburst hanging above the stage which DID ignite and the surrounding observers in the hall thought it was a regular pyro test since they knew the fire officer/local authority were in to inspect us... We were naturally, very embarrassed and were questioned further about the system. We had selected the battery control system because of the ease of not having to find a 13a socket near to where we were going to operate the unit... Our resolve to appease the inspection was to revert to the mains system (Le Maitre 6-24) and beg some extra long 13a extension cables from the venue. We quickly learnt the lesson on that occasion and have never done it again. Your moderators personal view on this... It is far better to be informed of a situation like this than not to share it with others or wait for a serious accident to happen. And thank goodness for the internet forums and company reps like Mark that have already stated that he will convey the concerns of the community to the directors and R&D of his company. Hope that this helps Lincoln Link to comment Share on other sites More sharing options...
Suzette Posted January 31, 2005 Share Posted January 31, 2005 I have recently purchased the Le Maitre 6-way battery controlled system --- and was unaware that it would still fire without batteries .... however having now read these posts I will be extra, extra careful about button pressing - with or without batteries!!! Link to comment Share on other sites More sharing options...
Dave R Posted January 31, 2005 Share Posted January 31, 2005 Hi, as a member of the R&D team at Le Maitre Ltd, I hope you don't mind a couple of comments here. Mark has made me aware of this issue relating to residual energy remaining in the storage capacitor of the 2 and 6 way firing devices. The nature of the circuit and the design philosophy dictate that this will be a characteristic of these devices. Basic Safety protocol would automatically assume that if a pyrotechnic device is attached to any form of firing mechanism, and that a safety lock is disabled (Key inserted and turned), the channel to which that device is connected is enabled (switch activated) and that the Fire button is pressed, then that pyrotechnic device is capable of igniting. It should, under no circumstances, be assumed that any firing mechanism will never discharge and create an ignition condition. (doesn't apply to you though Lincoln!!!!!!!! my hero - I'm not worthy )The same principle should apply when testing devices in situ. Always assuming a ignition condition, ensures correct safety procedures are being followed. An analogy would be that of picking up a gun, checking there are no bullets in the magazine, and pulling the trigger, whilst aiming it at someone. Try getting away with that at your your local gun club! But having said all that, the point raised is very valid in the fact that this information does not appear in the instruction manual, and it is appreciated that this has been pointed out.We will be adding a warning note to the instruction manual as soon as this can be instigated. As a final note, should a complete discharge of energy be required after battery removal, just fire a few times into a shorted output channel. Dave Roffey Le Maitre Ltd Link to comment Share on other sites More sharing options...
themadhippy Posted January 31, 2005 Share Posted January 31, 2005 how about adding a relay to the unit that shorts the outputs together when the power is removed?, Link to comment Share on other sites More sharing options...
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