AN-001 – Interlocking a LaserPak & TECPak with a Relay
The following application note outlines how to use the analog interface of the 585 Series TECPak to control the interlock signal on the 485 Series LaserPak to prevent operation of the laser unless the 585 Series TECPak output is enabled.
IMPLEMENTATION
The following circuit uses a relay to provide an isolated contact closure for the interlock pins of the 485 Series LaserPak’s output connector.
There are many possible choices for the N-channel FET, but it must have the following capabilities: Vds of 5V or greater; current handling of at least 100mA; and a logic-level FET, as the gate voltage will only be 3.3V.
Likewise, there are many relay choices, but the coil voltage must be 4.5-5V, and draw less than 50mA when operating.
