THORLABS MX40G Series, Руководство пользователя

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MX40G, MX70G Series of E-O Converters Chapter 6: Control and PC Connections
Page 32 TTN116413-D02
6.2 The Laser Safety Interlock
The laser is equipped with a phono-type interlock jack located on the back panel. To enable the laser source, a short circuit
must be applied across the terminals of the interlock connector. The shorting device (interlock pin) installed in all units shipped
from Thorlabs performs this function. Leave the shorting device installed unless using an external safety circuit or other type of
remotely controlled switch to enable laser output.
Making use of the Interlock feature requires the appropriate 2.5 mm phono-type plug, which is diagrammed in Figure 48(a) and
is readily available through most electronics retailers. The plug should be wired to the external safety circuit or switch and then
plugged into the back panel’s interlock jack in place of the shorting device. The electrical specifications of the interlock jack are
listed in the following table, and the circuit schematic describing how the interlock jack is connected inside the laser head is
shown in Figure 48(b).
Specification Value
Interlock Switch Requirements
Must be Normally Open Dry Contacts
Apply no External Voltages to the Interlock Input
Type of Mating Connector 2.5 mm Mono Phono Jack
Open Circuit Voltage
<5 VDC
(Center Pin is at 5 VDC, Ring is Ground)
Short Circuit Current (Typical) 7 mA
Connector Polarity
Tip is Ground, Barrel is at 5 VDC Max
The user’s safety circuit must be attached to the phono plug and wired such that the ring and center pin are shorted when it is
safe to enable the laser. The laser will be enabled when connection is closed. If it changes to an open state, the laser source
will turn off.
(a) Diagram of a Phono-Type Plug (b) Internal Electrical Connections of the Interlock Jack
Figure 48 The interlock circuitry internal to the laser head applies a 5 VDC bias across the ring and center pin
of the plug. An external circuit that shorts the ring and center pin enables the laser.
Ring
Center Pin
Center Pin
+5.0 V
1.00 k Ω
10.0 k Ω
Ring
GND