User Manual

Table Of Contents
Safe Torque-Off (STO)
Advanced Digital Motor Controller User Manual 41
2. STO Fault LED at Roborun+ utility in failure
This failure can have several internal and external reasons. If the failure is shown please
check the cabling and the signals to STO 1 and STO 2. Both signals much have at all times
the same level.
Check that the STO jumper is set correctly and STO is configured correctly
Check wiring
Check cabling for short circuits or open circuits
If the failure persists, contact Roboteq support.
IMPORTANT WARNING
Same status LED pattern is used for undervoltage and overvoltage faults and that should
not be confusing. If STO fault appear it is normal for the controller voltage to be off and
undervoltage fault to trigger. Either way this Status LED pattern indicates a situation that
should be treated with caution.
Firmware implementation
The STO circuit will operate regardless of the MCU activity. However, when operating nor-
mally the MCU will perform the following functions:
1. Self-test that the STO circuits and switches are functional. This is done every time
the controller is powered on. It can also be done at any time during the controller
from external user commands from the system’s PC or PLC (check command sec-
tion). The self-test can also be initiated by the controller itself using its scripting lan-
guage, at periodic time intervals, or any other user-define rule(s).
If the self-test fails, the controller will stop driving the MOSFETs and set a fault flag
that can be monitored by the PLC/Computer. It can also activate one of its digital
outputs to indicate the fault.
2. The STO inputs are monitored continuously every 1ms. If one or both STO inputs are at
level zero and the MOSFET driver supply voltage has not dropped, an STO fault is detect-
ed. The STO fault flag is set. A user digital output can be activated to indicate the fault.
Installation – Maintenance
The STO circuit needs to be tested before first installation and at least every 3 months
according to the below sequence:
1. Activate STO (both logic level 0)
2. Check that STO is active (through Roborun+ Utility/Serial)