Nortech Systems Adept RS-232/TERM - Manual (Page 106)

Appendix A - sDIO Module
106 Adept SmartController User’s Guide, Rev. E
sDIO Outputs
The 32 output channels are arranged in four groups of eight. Each group is isolated from
the other groups and is optically isolated from the sDIO circuitry. The eight outputs
within each group share a common power supply and a common ground.
The outputs are accessed through the two female 44-pin D-sub output connectors on the
front of the sDIO. Each connector provides access to two output groups. Each group
requires 19 pins: 8 output signals, 1 test signal, 9 power supply (all tied together), and 1
power supply ground reference. When an output is on, current will flow in through the
power supply pins and out through the output pins. This type of output is considered
sourcing, that is, in the “on” condition, current flows out of the output pin. See
Figure A-8
on page 109 for details on typical digital output wiring.
Testing sDIO Outputs
Like many solid-state I/O systems, when an output is off, a small leakage current will
flow out of the output. This will raise the potential of the output to the power supply
voltage level if there is no load. With a load connected, the output will function normally.
However, if you need to test the output with a voltmeter with a load disconnected, you
will get a false reading. The test signal provides a bias that can be used as a pull-down
resistor for system-level troubleshooting. When this is connected to an output, the output
will assume the ground potential when it is off.
sDIO LEDs
A pair of two-color LEDs on the sDIO module indicate link status over the IEEE 1394
connection and system status. The upper LED lights green when an IEEE 1394 connection
is established. The lower LED blinks green when the software is active and switches to
solid green after the controller software has found and configured the DIO block. The
lower LED lights solid red whenever an output fault (excessive current or temperature) is
detected on any of the 32 outputs. Refer to
Table A-3 on page 107 for information about
the LEDs and Figure A-6 on page 103 for information on their location.
NOTE: A fault indication is the result of an over-temperature or
over-current condition on one or more of the outputs, usually due to a
short-circuit condition. As a result, the output driver IC will oscillate on
and off as the chip tries to drive the load.
Note that this red fault LED is active only when:
• An extended output (for example, a SIGNAL in the range of 33 to 64) has been
turned on by a V + command.
• An activated output has a thermal overload problem, usually due to a short in the
user’s wiring from the output pin to the user’s ground.