APF Spectrograph Electronics
Board Designs
Triple Haff-Effect Limit Board with Forward and Reverse Switches Inverted, 
EL-1395
Schematic: schematics/APF/boards/F_R_limit inverted_board.pdf
Page last updated: February 8, 2012
Simplified Drawing
The EL-1395 circuit board simply contains 3 Cherry VN101501 digital vane switches and two 2N4401 transistors. The transistors are used to invert the sense of the forward and reverse limit switchs. This board is used only on the Dewar Focus stage. Due to mechanical limitations, this stage requires that both the forward and reverse limit sense be inverted. The switches are spaced at 0.8" between forward and reverse limit and 1.0" between the reverse limit and Home sensor. The board has a 6-pin connector, J1, that supplies +5V and GND and four output pins. The outputs correspond to the three sensors and a limit connected signal. The LIM CONN signals the controller if for any reason the connector has been disconnected.
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