ENABLE and SAFETY ENABLE input signals comply with following electrical characteristics:
Nominal excitation voltage
Min excitation voltage
Max excitation voltage
Max steady state current (25°C)
Max in-rush peak current
SAFETY OK and DRIVE OK feedback relays characteristics are shown in
Nominal output voltage
Maximum Isolation Voltage
Max current (25°C)
Normal use of STO safety function shall follow a predefined sequence as for enabling as well as
for disabling safety function.
DISABLING SAFETY FUNCTION
Drive is in stop condition, both enable signals are disabled. In order to disable STO function
properly following action sequence applies:
1. SAFETY OK, DRIVE OK signals are checked for congruency
2. SAFETY ENABLE signal issued high (24v applied)
3. ENABLE is issued high (24v applied)
4. FEEDBACK signals DriveOK and SAFETY DISABLED are checked for congruency
5. START command can now be issued to start motor and provide power
ENABLING SAFETY FUNCTION
Drive is running and powering a motor, both enable signals are enabled. In order to activate EXP-
SFTY-ADV function properly following action sequence is applied:
1. STOP command is issued to stop motor and power generation
Finally SAFETY ENABLE
Should ENABLE and SAFETY ENABLE be tied together (both electrically or logically) it must
assured that they delays exceeding 4ms is not introduced. In case of SAFETY ENABLE be issued
high before ENABLE drive will go into interblock mode and will allow motor to start before ENABLE
is correctly taken low and high again.
Table 8 ENABLE-SAFETY ENABLE electrical levels.
Table 9 SAFETY OK relay characteristics.
signal is issued low