Corrected from:
i950 servo inverter: from V01.02.03.0985
Response of the new version: The holding brake is always applied immediately when the inverter is inhibited via STO.
Brake application is no longer delayed due to a selected error response.
What happens?
The inverter is inhibited via the STO function (safe torque off) by controlling the digital inputs SIA/SIB.
The holding brake is, however, only controlled with delay so that the load is accepted correspondingly later.
The time delay depends on the execution time of the error response. Especially the setting under 0x2826 'Quick stop: Time-out for fault' is important (Lenze setting: 4s).
When does this behaviour occur?
"Control via state machine of device" (0x2820:1 = 0) is selected as brake mode and the internal i950 brake logic is used.
The parameter 0x605E 'Response to quick stop' is not set to 'Controller inhibit' (0x605E = 0), but to 'Quick stop' (0x605E:0 = 2 or -2). Lenze setting: 0x605E = -2.
- The STO function is activated while the selected error response is executed. E.g. after occurrence of an EtherCAT error.
The described behaviour may also occur if the following class-2 errors (light faults) occur instead of the EtherCAT error:
- Error code 0x4380: Motor temperature sensor
- Error code 0x7303: Encoder error
- Error code 0x7380: Hiperface communication error
- Error code 0x8181: EtherCAT communication
- Error code 0x8700: EtherCAT sync loss
Which products are affected?
i950 servo inverter
Short-term measures:
Set the parameter 0x605E 'Response to quick stop' to 'Controller inhibit' (0x605E = 0).
As an alternative, use the brake logic in the controller.
For this, do not change the default i950 brake mode: "Control via control word from ext. controller" (0x2820:1 = 1).
Make sure that there is no direct operative relationship between STO and the EtherCAT bus.
Evaluation/recommendations:
The internal i950 brake logic is usually only used for applications with third-party controllers.
When using Lenze controllers with FAST Motion, brake control is performed via the Lenze controller.
The probability of occurrence of the described behaviour is considered to be rather low.
For applications with active loads, e.g.: hoists, please refer to the "risk analysis" to be performed by the mechanical engineer. The mechanical engineer usually has to provide for a second independent protection system, if major damage may be caused by component errors.
