XC2 Hardware Manual
Chapter 2: Installation and Configuration
2.4. Safe Torque Off Input (STO)
The STO circuit is comprised of two identical channels, each of which must be energized in order for the
XC2 to produce motion. Each channel is opto-isolated and provides individual connections to each terminal
of the opto-coupler LED. Current limiting resistors are provided internally and the STO inputs are designed to
work with 24 V signals.
NOTE:
The XC2 might be equipped with an STO bypass plug. The bypass plug defeats the STO safety
circuit and allows the system to run at all times. To use the STO safety functionality, remove the plug and
make connections as outlined in this section.
NOTE:
The application circuit and its suitability for the desired safety level is the sole responsibility of the
user of XC2.
Table 2-21:
STO Connector Pinout
Pin #
Signal
Description
In/Out/Bi
Connector
1
Power
Used to defeat STO by connecting to
STO 1 IN and STO 2 IN
2
STO 1 IN
STO Channel 1 Positive Input
Input
3
RETURN
STO Negative Input
Input
4
STO 2 IN
STO Channel 2 Positive Input
Input
5
Power Supply -
Used to defeat STO by connecting to
RETURN
Table 2-22:
Mating Connector Part Numbers for the STO Connector
Description
Aerotech P/N
Phoenix P/N
Tightening
Torque (Nm)
Wire Size:
AWG [mm
2
]
5-Pin Terminal Block
ECK02393
1827622
0.22 - 0.25
2.5 - 0.05 [14-30]
Table 2-23:
STO Electrical Specifications
Status
Value
STO off (motion allowed )
18-24 V, 7 ma
STO on (safe state entered, no motion)
0-6 V
Recommended Wire Gauge
22-26 AWG (0.5 - 0.14 mm
2
)
STO System Power Supply
PELV
STO Wire Length (maximum)
50 m
shows one safety device connected to multiple XC2s in a parallel.
www.aerotech.com
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