Connecting Output Signals
Adept IO Blox User’s Guide, Rev B
31
3.5
Connecting Output Signals
The eight digital outputs share a common, high side (sourcing) driver IC. The driver is an
eight channel device designed to supply any kind of load with one side connected to
ground. It is designed for a range of user-provided voltages from 11 to 24 VDC, and each
channel is capable of up to 0.7 A of current. This driver has over-temperature protection,
current limiting, shorted load protection, and under-voltage shutdown. In the event of an
output short or other over-current situation, the affected output of the driver IC turns off
and back on automatically to reduce the temperature of the IC. The “OVRTMP” LED on
the IO Blox indicates this condition. The driver is powered by the user-provided voltage
supply and the driver control inputs are optically isolated from the IO Blox control logic.
NOTE:
An IO Blox Auxiliary Power cable is provided in the IO Blox kit for
Adept Python Linear Modules to provide 24 VDC user power to IO Blox.
See
The outputs are accessed through a 9 x 2 terminal block on the IO Blox. The upper row of
this terminal block starts with the “+V” supply input and continues with the eight output
pins. The bottom row of pins are all shorted together for ground connections. This
arrangement allows the two wires from the power supply to be connected at one end and
the two wire connections to each load to be connected at the appropriate output. When an
output is on, current will flow in through the power supply pin, out through the output
pins, and then return through the ground bus of the terminal block back through the
power supply connection. This type of output is considered sourcing, that is, in the “on”
condition, current flows out of the output pin. See
for details on
typical digital output wiring.
Total Current Limitation
Although the capacity of a single channel is 0.7 A, the IO Blox cannot sustain 0.7 A on all
outputs simultaneously. Due to heat sinking constraints, the maximum current for all
outputs is 2.5 A in a 50
°
C environment and 3.7 A in 25
°
C.
