Jon Elson's Machining Page

Schematics of Connections for EMC and Servo-to-Go

Encoder Schematic This is how to connect up to 3 single-ended encoders to the Servo-to-Go card. Single-ended means the encoder provides only a single signal for each quadrature channel, rather than complementary differential signals. Note that the 50-pin Servo-to-Go connector P3 does not provide a source of +5 Volts to power the encoders. If your encoders are low power types, you can power them from the Servo-to-Go card, but you have to get the power from P1 or P2. Pin 49 of both of these connectors provide +5 volt power. STG notes you should not take more than 500 mA from the board. It has self-resetting PTC current limiters on the board.
Limit Switches This shows how to connect limit and home switches to the Servo-to-Go card's P1 connector. The switches are not isolated, and are energized by the +5V from P1, via the computer's power supply. It probably is best to set up the limit switches so that they are normally closed, and opening the switch contacts indicates the limit condition to the computer. EMC allows you to select either polarity to be the limit condition.
Limit Sw. with OptoCouplers This performs the same function as the above drawing, but with optical isolation between the switches and the computer. The switches must be powered by an isolated +5 V power supply.
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