Wiki source code of DVI7911 Junction Board

Last modified by Michael Sibayan on 2022/05/03 16:48

author	version	line-number	content
		1	= Overview =
		2	The purpose of this board is to combine cabling of five (5) Davis Instruments anemometers into a pair (2) of 8-conductor cables and handle external circuitry required for data acquisition with these devices. Each Davis Instruments anemometer requires an excitation voltage of approximately 3.3 VDC and a pull-up resistor on the relay output of cup anemometer. A simple diagram of the internal circuitry of the Davis Instruments device is shown below:
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		4	[[image:DVI7911_Internal_Circuit.png\|\|style="display: block; margin-left: auto; margin-right: auto;"]]
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		6	The normally open single pole single throw (NO-SPST) relay is actually a reed switch that closes for approximately 4ms when the cup anemometer passes the correct position. The potentiometer wiper is controlled by the wind vane. In order to monitor the junction box provides excitation regulation at 3.3VDC (from a 5VDC source), and pull up resistors for the reed switch. Below is the circuit diagram used on the junction board:
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		8	[[image:DavisAnemometer-JunctionBox-Circuit.jpg\|\|style="display: block; margin-left: auto; margin-right: auto;"]]
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		10	= Images of the board, layout, and pin assignments =
		11
		12	Pin assignment:
		13
		14	=== Plugs 1 through 5 ===
		15	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)N/C
		16	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)+3.3VDC
		17	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Potentiometer output
		18	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Reference (Ground)
		19	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Relay output
		20	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)N/C
		21
		22	=== Plug A ===
		23	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Device 1 relay output
		24	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Device 1 potentiometer output
		25	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Device 2 relay output
		26	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Device 2 potentiometer output
		27	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Device 3 relay output
		28	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Device 3 potentiometer output
		29	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Device 4 relay output
		30	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Device 4 potentiometer output
		31
		32	=== Plug B ===
		33	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Device 5 relay output
		34	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Device 5 potentiometer output
		35	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)N/C
		36	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)N/C
		37	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)N/C
		38	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Voltage monitor (output of regulator)
		39	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)+5VDC (supply voltage)
		40	1. (% style="font-size: 14px; background-color: rgb(236, 236, 236);" %)Reference (Ground)
		41
		42	[[image:DVI7911_JunctionBoard.JPG\|\|style="display: block; margin-left: auto; margin-right: auto;"]]
		43	[[image:DVI7911_Board_Top.png\|\|style="display: block; margin-left: auto; margin-right: auto;"]]
		44	[[image:DVI7911_Board_Bottom.png\|\|style="display: block; margin-left: auto; margin-right: auto;"]]
		45	[[image:Davis-Anemometer_JunctionBox.bmp\|\|style="display: block; margin-left: auto; margin-right: auto;"]]