#11, M1S: Four Open Collector Outputs
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Function: Four open collector outputs
Form factor: M1S
Category: Output module
Special needs: [SER] (if reader emulation is desired)
Power requirements: 5V/50mA
See also: #16
Transistors are rated for the maximum voltage of 24V and the maximum per-channel current of 0.5A. Note that the maximum current should not be exceeded even at lower voltages. Do not apply negative voltage!
To open a transistor, set the corresponding control line LOW. When left unconnected, control lines default to HIGH (and, hence, transistors will be closed).
Combine this Tibbit with terminal block devices -- #20 (nine terminal blocks) or #21 (four terminal blocks). Note that #21 doesn't provide the ground line, and using this Tibbit requires the ground line between the outside world and your system. Hence, if you use Tibbit #21 you will need to "steal" the ground somewhere else.
One additional possible use of this Tibbit is for the emulation of clock/data or Wiegand card readers. Our programmable devices (such as TPP2 and TPP3) have the unique ability to output data in the clock/data or Wiegand format. This is achieved through the ser. object running in the clock/data or Wiegand mode. Card readers usually have open collector outputs so this Tibbit is ideally suited as the hardware front-end for the job. For this to work, the Tibbit has to be connected to the TX and RTS lines of the CPU's UART (see [SER]).
As with many "real" readers, the equipment on the receiving end will need pull-up resistors.
There are four red LEDs which are connected to four control lines. All LEDs are buffered (using logic gates) and light up for the LOW state of control lines (i.e. when transistors are in the opened state).