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ISOLATED DIGITAL INTERFACE - STP100C
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The STP100C is used to safely isolate digital inputs (in the range of 0-3.3 V or 0-5.0 V) and outputs to and from an MP System (MP100 or MP150).

The STP100C connects the MP System to computers running presentation or psychophysiological stimulation applications.

• STP100C interfaces with SuperLab via a 3-meter DB37 F/F ribbon cable (CBL110A, included)

• For systems that use a printer port interface—such as E-Prime, DirectRT, MediaLab, Inquisit, or Vizard VR Toolkit—order STP100C-C, which uses a 3-meter DB25 M/F ribbon cable (CBL110C, included)

The STP100C also includes output to drive solid state relays and incorporates a BNC accessible External Trigger input line. All inputs and outputs associated with the STP100C safely isolate connections to the MP System to 1500VDC isolation. The STP100C Isolated Digital Interface provides:

• 8 lines for digital data input
• 8 lines for digital data output
• 4 lines for TTL output
• 1 isolated external trigger input

Digital Lines—Use to connect digital signals (TTL compatible) from any mains powered external equipment to an MP System when the system also connects to electrodes attached to humans. All lines on the STP100C are optically isolated to 1500 VDC compliance.

Output Drives (for relays)—The STP100C can drive up to four (4) solid state relays directly via MP System Digital I/O lines 0-3. MP System Digital I/O line 4 is used as an enable to activate these drive lines.
          ON = low (0V) signal on I/O line 4
          OFF = high (5V) signal on I/O line 4
The output drives (for relays) have 0 to 5 V output voltages and are current limited with 200 ohm resistors. This means that for solid state relay drive requirements, output current will be limited to approximately 20 mA, assuming an optically isolated solid state relay input diode drop of 1.2 V. Nearly all solid state relays can operate with as little as 5 mA of current drive.

The STMISOC is designed to work with digital inputs in the range of 0-3.3 V (which is increasingly common with laptop I/O cards and printer ports) or 0-5.0 volts.

Isolated External Trigger Input—The optically isolated external trigger input is TTL compatible. This line is accessible via a BNC female connector (labeled TRIG on the front of the STP100C) and connects to the MP unit External Trigger input via optical isolation, compliant to 1500 VDC. The voltage range for this drive must be 0-5 V (TTL input levels).

When the STP100C trigger is unused, it is pulled to a high state (+5 V) via an internal 100 kohm resistor. To properly drive this line, connect a standard TTL driver to this port. For non-TTL type drivers, the low voltage applied to a trigger must be between 0 and 0.5 V. The high voltage applied to the trigger must be between 2.5 and 5 V. The maximum recommended source impedance of the driver should not exceed 1 Kohm.

Additionally, to use the STP100C external trigger in a manual mode, the input can be pulled low with an external switch connected between the trigger input and ground.

To externally trigger MP Unit acquisition, send a TTL signal to the External Trigger of the STP100C (TRIG). This line connects to the MP Unit External Trigger via optical isolation.

To use an MP System line that is normally dedicated to an I/O input (lines 8-15) as an External Trigger drive, use a JUMP100 jumper wire to connect that line directly to External Trigger (EXT T) on the back of the UIM100C.