Deleted
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Post by Deleted on Nov 3, 2010 16:31:42 GMT
As I understand it, the first six D stock refurbs had holes/bays cut in the rear of the DM roof to fit a GPS transmitter. On later refurbs, the transmitter was incorporated in the roof itself (correct?).
Have the "cut" trains been reverted to the "standard", or are they still running around showing their GPS transmitters to everyone above platform level?
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Post by Dstock7080 on Nov 3, 2010 16:42:42 GMT
Actually, it was the first 7 trains and they are still like it. tinyurl.com/32ufwcnAs refurbished: 7002+7021 7012+7081 7074+7003 7088+7005 7106+7119 7116+7027 7124+7047 |
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Deleted
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Post by Deleted on Nov 3, 2010 16:45:31 GMT
So annoying I don't find out stuff like this just before I go to London, but find out just after I get home  Do you (or anyone else) have a list over the cars/units concerned? |
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Post by Deleted on Nov 4, 2010 9:17:04 GMT
Why were they installed in the first place?
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Post by Deleted on Nov 4, 2010 9:37:28 GMT
Why were they installed in the first place? For voice announcements I believe. in tunnel sections, a wheel spin counter would be used instead due to no GPS signal. |
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Colin
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Post by Colin on Nov 4, 2010 20:41:46 GMT
Spot on  |
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Post by Deleted on Nov 4, 2010 21:00:17 GMT
I hope the wheel spin counter can be adjusted to take into account different wheel sizes after a visit to the wheel lathe.
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Colin
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Post by Colin on Nov 4, 2010 21:19:33 GMT
It works to a tolerance of +/- xx number of revolutions, so yes, it most certainly does take account of differing wheel sizes.
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rincew1nd
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Post by rincew1nd on Nov 4, 2010 21:47:54 GMT
I'm guessing it's also fed by door opening, so will zero at each station?
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mrfs42
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Post by mrfs42 on Nov 5, 2010 0:55:53 GMT
I'm guessing it's also fed by door opening, so will zero at each station? <not a D stock answer> Yes - provided that the opening is within a particular range - IOW emergency openings of doors away from coordinates wouldn't reset the counter, but ISTR get stored. Doesn't the CSDE equipment provide some form of positional reference too? </not a D stock answer> |
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Colin
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Post by Colin on Nov 5, 2010 5:19:17 GMT
As far as I'm aware, CSDE (Correct Side Door Enable) has no bearing on the DVA (Digital Voice Announcer) system.
As you say, the system works on the basis that it will zero the wheel revolution count only if the doors are opened within the tolerance expected. Repeated door opening will not move the system forward to the next station - only wheel revolutions (and/or GPS when outside) will do that.
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Post by t697 on Nov 6, 2010 16:23:38 GMT
The GPS devices on D78 roofs are receivers of course, not transmitters as someone thought. The later version on D78 refurb is a much lower profile and didn't need the complicated roof recess to stay within gauge. In fact it just needed a hole drilled!
Colin's explanation on the distance count for CIS announcements is pretty accurate.
When you set up the journey starting at an 'open' station, the system automatically knows the start station from GPS so you just need to set the route and destination.
When you set it up at a tunnel station like Tower Hill, it has 'forgotten' its location at the end of the previous trip and you have to set the start station too.
If you don't do this until after you start, you should set the next station as the 'start'. This explains those odd trips westbound from Tower Hill where it gets all confused until it gets a GPS fix. Probably the driver set the CIS after starting and put in Tower Hill as start not Monument.
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