i950, i750, i700 with holding brake and CiA fault reaction 0x605E=[-2]: Closing of the brake only takes place during the transition to CiA state 'Fault'
Question:
Control of a holding brake, especially for active loads, e.g. hoist applications:
What must be observed during parameterisation if the extended quick stop (QSP) of the inverter (0x605E= [-2]) is used?
Answer:
The behaviour of the inverter (reaction) when responding to monitoring can be adapted by the user to the requirements of the application.
Especially for active loads with control of a holding brake, e.g. in hoist applications, an adjustment of the parameterisation may be necessary or useful.
0x2826 'Timeout fault reaction', default: 0x2826 = 4 s
Parameterisation recommendations if a sag or a significantly extended stopping distance cannot be accepted in the application:
Possibility: 0x605E = [0]: Set 'Controller inhibit' and leave 0x2826 in default.
Possibility: Leave 0x605E = [-2] in default and reduce the timeout, e.g. to 0x2826 = 0 s.
This central setting then applies to all monitoring from the list of non-'serious' errors (see below).
The effects of this fault reaction in the machine environment / process are to be cross checked by the user.
Different fault reactions of the inverter can be parameterised via the parameter CiA fault reaction 0x605E:
0x605E = [0]
Controller inhibit
-> corresponds to the immediate change to the 'Fault' state, in which the inverter is disabled and the holding brake is closed and .
0x605E = [2]
Quick stop (QSP)
-> The motor is first brought to a standstill with the quick stop function (QSP) of the inverter. The duration of the stop is determined by the delay 0x6085. During the stop, CiA state 'Fault reaction' is active. A change to the CiA state 'Fault' with closing of the brake and controller inhibit only occurs when one of the following conditions is fulfilled: 1.: the standstill has been reached or 2.: the monitoring time has expired ('Timeout fault reaction' 0x2826).
0x605E = [-2]
Extended quick stop (QSP)
-> The motor is first brought to a standstill with the inverter's quick stop (QSP) function, as with 0x605E = [2]. The change to the CiA state 'Fault', with closing of the brake and controller inhibit, takes place under the same conditions as for 0x605E = [2].
However, the following exception applies: If the QSP function cannot be executed, e.g. because there is an encoder error, the short-circuit braking function (KSB) is activated as a substitute for braking the movement for motor type SM and the DC braking function (DCB) for ASM. The achievable torque of these controlled processes is usually lower than with servo control, but the strategy here is to stop the movement as actively as possible in order to avoid damage to the mechanics.
If the motor feedback system is not functioning (error ID: 0x7303), the motor can no longer be operated in servo control and thus no quick stop (QSP) can be executed.
Stopping the movement takes longer with the substitute functions KSB and DCB and their significantly lower braking effect, and active loads can sag if the achievable torque is not sufficient to hold the load.
In addition, without functioning feedback, the standstill cannot be detected, so that the 'Error' state is only reached after the monitoring time 'Timeout for error reaction' 0x2826 has elapsed. Accordingly, the holding brake is only closed at this time.
The motor holding brake is controlled via the inverter depending on the CiA status:
in the CiA state 'error', or at the transition to it, the brake is closed
in the CiA state 'error reaction', the brake remains released.
CiA402-Norm:
The CiA state 'Fault response' is a transitional state in which a manufacturer-specific response can take place before switching to the CiA state 'Fault' and the inverter is disabled.
This error reaction only occurs for errors that are not 'serious'.
List of non-'serious' errors:
Error
i700
i950/i750
0x4380 - Error engine temperature sensor
X
X
0x4383 - Error motor temperature sensor (load sensor / master sensor)
X
0x7303 - Error motor encoder
X
X
0x7304 - Error load transmitter / master encoder
X
0x7380 - Motor encoder communication error
X
X
0x7382 - Load generator/conductor Communication error
