Technical data   35
Technical data
Contents of this chapter
This chapter contains the technical details of the ASTO-11 and ASTO-21 boards, the 
safety data for the STO components and example information of safety relays and 
activation switches. It also lists the related standards and directives, and contains 
declarations of conformity with the European Machinery Directive.
STO components
 ASTO-11/21 board
ASTO-11 and ASTO-21 board
Supply voltage range +24 V DC +/- 10%
Current consumption 40 mA (20 mA/channel)
Supply cable A single-shielded twisted pair
Maximum cable length 300 m
Conductor min. cross section
0.5 mm
2
, 20 AWG
Logic levels "0" < 5 V DC, "1" > 17 V DC
Ambient temperature 0…50 °C
Relative humidity Max. 90%, no condensation allowed
Altitude in operation 0…2000 m
ASTO-11 board
Dimensions  167 x 128 x 52 mm (height x weight x depth)
Weight  0.75 kg
Degree of protection IP20