Lenze E94ARNE Regenerative power supply - Manual (Page 28)

9400 regenerative power supply module | Parameter setting
Regenerative power supply module application
Parameterising the brake chopper/brake resistor
28
L
EDS94ARNExxxx EN 2.3 - 06/2014
 C00138 displays the calculated utilisation of the brake resistor in [%].
– A 100 % utilisation corresponds to the continuous power of the brake resistor
resulting at the maximum permissible temperature limit of the brake resistor.
– The calculated utilisation is also provided as the oscilloscope signal
Common.dnI2tBrakeResistor to check the braking operation while the system is
running
(scaling: 2
30 ≡ 100 %).
 If the utilisation exceeds the advance warning threshold set in C00572 , the message
"Brake resistor: I2t > C00572" is entered into the logbook and the response set in
C00571 (default setting: "Warning") is activated.
 When the utilisation reaches the limit value (100 %):
– The response set in
C00574 (default setting: "No response") is activated with the
corresponding effects on the state machine and the inverter.
– The activation of the brake chopper is reset to the permanently permissible pulse-
no-pulse ratio (taking into account the parameterised brake resistance). (The brake
chopper is activated with 4 kHz, which means that it can be switched on/off at
minimum intervals of 250 μs.)

Stop!
The brake resistor can be thermally overloaded. Carry out protective measures
suitable for the system, e.g.:
• Parameterisation of an error response in
C00574 and evaluation of the
parameterised error message in the application or machine control.
• External wiring using the temperature contact on the brake resistor (e.g.
interruption of the supply via mains contactor and activation of the
mechanical brakes).

Note!
If the system is dimensioned correctly, this monitoring function should not
respond. If individual rated data of the connected brake resistor are not known,
they must be determined "empirically".
From software version V2.0 onwards, C00571 and C00574 additionally provide
the error response "Brake chopper is inhibited".
• If this error response occurs, the brake chopper is inhibited without providing
feedback to the device control. Instead, feedback is provided via the
LI_bChopperOffByTrouble output of the LS_LineInterface system block.
• If the corresponding trigger threshold is fallen below by 5 %, the pulse inhibit
of the brake chopper is deactivated again and the status signal
LI_bChopperOffByTrouble is reset to FALSE.