Installation manual
Publication 1394-IN002B-EN-P — February 2004
Interconnect Diagrams B-9
Thermal Switch and Brake 
Interconnect Diagrams
This section provides thermal switch and brake interconnect diagrams.
Understanding Motor Thermal Switches
Thermal switches, internal to each servo motor, can be wired in series 
to protect the motor from overheating. In the event of a fault 
condition, the switch opens and the motor responds to the system 
configuration. The explanation and example diagrams that follow 
show how to wire motor thermal switches to your system module.
Depending on the series of your 1394 axis module, your customer 
control devices may require isolation from the motor’s conducted 
noise. When using 1394 (Series A and B) axis modules, an isolated 
24V dc power supply and relay is recommended. 1394 (Series C) axis 
modules contain internal motor brake and thermal switch filtering and 
do not require the isolation power supply and relay.
Individual thermal fault monitoring can be achieved by wiring each of 
the motor thermal switches from the motor, through TB1/TB2 on the 
axis module, or directly from the motor to one of four dedicated 
thermal fault inputs on the system module. Your 1394 system can then 
be configured to monitor and disable one or all four of the axes. As an 
alternative, you can wire the thermal switches into the start/stop string 
to disable all axes when a fault occurs.
How Your Feedback Cable Affects Thermal Switch Wiring
The examples shown on the following pages are for 1326AB/AS servo 
motors with resolver feedback (using 1326-CCU-xxx feedback cables). 
The motor thermal switch leads are in the motor power cable and 
attach to TB1 of the axis module (refer to figures B.7 and B.8 for 
motor/axis module interconnect diagrams).
1326AB (M2L/S2L) motors and MP-Series motors (both resolver and 
high resolution feedback) use 2090-CDNFDMP-Sxx feedback cables. 
The motor thermal switch wires are in the motor feedback cable and 
attach directly to the feedback connector on the bottom of the 1394 
system module. Refer to figures B.6 and B.7 for motor/system module 
interconnect diagrams).
Thermal Switch Interconnect Diagrams
The example in Figure B.9 shows 1394 (Series C) axis modules with 
internal brake and thermal switch filtering. Separate isolation power 
supply and relay are not required. Using this start/stop string 
configuration all axes are disabled when any one motor faults.










