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TECPak
User’s Manual
For purposes of the TEC:DIO commands, this dual-purpose input/output
function is considered both digital input 1
and
digital output 1.
Closing the Circuit
A +5V supply is used to bias the LED and goes through a 200
Ω
series resistor.
To close the circuit, there must be 4.5V or less across pins 1 and 8. A short
circuit can be used, but an LED can optionally be connected.
Depending on the type of LED, no resistor, series resistor, or parallel resistor can
be used. Red, green, and yellow LEDs may require no resistor. Blue LEDs are
too efficient to be wired with a series resistor and must use the parallel resistor
option.
When using a series resistor, the higher the resistor value, the dimmer the LED.
Do not use too high of a resistance value or it may always register as an open
circuit.
When using a parallel resistor, the lower the resistor value, the dimmer the LED.
Red, green, and yellow LEDs will typically use higher resistances (1k
Ω
or more),
while blue LEDs will use smaller resistor values (typically around 100
Ω)
.
No Resistor
Series Resistor
Parallel Resistor
Isolation and Multiple Interlocks
The LED/TEC Interlock Interface is electrically isolated from all other control
signals, and interlocks from multiple
TECPaks
can be wired in parallel through a
single switch.
Pin 8
Pin 1
Pin 8
Pin 1
Pin 8
Pin 1