gca179-en
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— | gca179-en [2018/11/12 08:56] (current) – created - external edit 127.0.0.1 | ||
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+ | ====== GCA179 Isolated Hall-sensor and/or reed-switch input unit. ====== | ||
+ | [[english|{{ | ||
+ | [[: | ||
+ | * [[mgv-overview-en|The GCA modules]] | ||
+ | \\ | ||
+ | |||
+ | ^^^^By Peter Giling ^^^^ | ||
+ | \\ | ||
+ | |||
+ | ===== Description ===== | ||
+ | |||
+ | The use of Reed-Switches is fairly common in garden railroad environment. \\ | ||
+ | It is cheap but face a few problems.\\ | ||
+ | First there is the ' | ||
+ | Rocrail does not have any problem with that, as long as it is just a simple feed-back. \\ | ||
+ | But using the switch as a wheel-counter (or magnet counter here) would give some problems.\\ | ||
+ | And specially this wheel counter is a very nice option, so far hardly anywhere available but in Rocrail it is standard.\\ | ||
+ | Second there is the fact that the contact given by a passing magnet is a rather short pulse. \\ | ||
+ | Most units in LocoNet or CANBUS useually need a pulse-length of minimal 50-75 milliSec.\\ | ||
+ | And the third fact is that reed-switches have a short functional life, when incorrect current is switched, either much too high or far too low.\\ | ||
+ | The last issue can be improved by switching the correct current as given by the specifications of the reed-switch, | ||
+ | \\ | ||
+ | For all three problems, there will be one simple solution.\\ | ||
+ | At the present moment I am finishing the development of GCA179 buffer board.\\ | ||
+ | It has 8 isolated inputs, useable for reed-switch and/or hall-sensor. where a for the reed-switch ' | ||
+ | The hall-sensor does not have any problem with that current.\\ | ||
+ | The isolated input enables the use of common Railpower wiring for the reed-switches, | ||
+ | This GCA179 has a connection to GCA50 / CAN-GC2 / GCA_PI02 which also provide the 5V supply for the on-board processor.\\ | ||
+ | This processor will extend a minimal pulse length in each input to a 0.1 Sec pulse for GCA50/ | ||
+ | At the same time, this longer pulse will sufficiently suppress the multi pulses from contact dender of a reed-switch. \\ | ||
+ | Hall sensors do not provide contact dender at all, in popular expression: one magnet is one pulse.\\ | ||
+ | |||
+ | ===== Specifications ===== | ||
+ | * 8 inputs with opto-couplers. | ||
+ | * minimum pulse length to activate output = 1 mSec. | ||
+ | * output pulse length standard 100 mSec minimal. | ||
+ | * separate 12 Volt 200 mA (100 mA for hall-sensors only) needed for sensor circuit | ||
+ | * two types of connector possible for 8 inputs : RJ10 or 2/3 terminal screw. | ||
+ | * up to 100 mtr wiring from sensor to GCA179 possible. | ||
+ | |||
+ | ===== The prototype ===== | ||
+ | | A working prototype is already a fact... | ||
+ | |{{: | ||
+ | |{{: | ||
+ | | The complete board with RJ10 sockets \\ for hallsensor connection | ||
+ | | = = = = **used screwterminals for hall/reed connections are 3, | ||
+ | |||
+ | ===== Hardware ===== | ||
+ | | | ||
+ | | | ||
+ | | {{: | ||
+ | | {{: | ||
+ | \\ | ||
+ | |||
+ | ===== Connection HallSensor or Reed-Switch to GCA179===== | ||
+ | {{: | ||
+ | |||
+ | ===== Firmware ===== | ||
+ | {{: |
gca179-en.txt · Last modified: 2018/11/12 08:56 by 127.0.0.1