Remedied from:
ECS power supply module ECSxE series, operating software V3.0
Behaviour of new version?
After connecting the 24 V supply the OC6 monitoring function for the internal brake resistor is now initialised with the value which has been saved when disconnecting the supply. However, maximally up to 80 % of the OC6 response threshold is accepted only. As a result, the OC6 monitoring for the utilisation of the internal brake resistor is activated in time even if the 24 V supply has been switched off in the meantime.
Which products are affected?
ECS power supply module ECSxE series, operating software V2.3
What happens?
The utilisation integrator of the OC6 monitoring function of the internal brake resistor is initialised with 0 after reconnecting the 24V supply. As a result, an utilisation degree which has already been achieved during operation before reconnecting the supply is not considered in the following. If the internal brake resistor is immediately extremely loaded after reconnecting the supply, the OC6 monitoring may be activated with delay and the internal brake resistor may be damaged and become highly resistive.
When does the problem occur?
The problem occurs if the internal brake resistor is actually overloaded as a result of which the OC6 monitoring would normally be activated. However, the activation is avoided due to the brief interruption of operation by switching the 24 V supply.
Possible diagnostics?
If there is no OC6 fault indicated although the application has continuously been operated with max. brake load, the temporary switching of the 24V supply is not critical.
If, vice versa, the OC6 monitoring is activated sporadically during continuous operation, it is possible that the brake resistor is damaged as described above. In this case the brake concept must definitely be checked and if necessary an external brake resistor is to be inserted.
Short-term measures/recommendations?
When interrupting the operation by switching the 24 V supply do not forget to include a waiting time of several minutes in order to ensure that the internal brake resistor can cool down. If the resistor is cold, the initialisation value 0 of the utilisation integrator is matching.
In case of braking powers in the limit range of the internal brake resistor use an external resistor with temperature contact if necessary.
Evaluation:
It is rather improbable that the situation described before occurs since in case of ECS multi-axis system the external 24 V supply is usually not switched for a short period of time even if the power is switched off.
If the brake resistor inside the device is actually damaged the resistor 'only' becomes highly resistive. It is safe to assume that consequential damages of further components inside and outside the device are not to be expected.
Published with service message No. 2007/26 und 2007/28
