Siemens SINUMERIK 840C - Manual (Page 438)

12.93 7 Drive Machine Data (SIMODRIVE Drive MD)
7.1.2 MSD MD (data description - SW 3)
Selection min/max memory 179
Default value Lower input limit Upper input limit Units
0000 0000 0002 Hex
Active
at once
This function allows variables to be monitored in the software. The address of the monitored
variable is entered in machine data "Address of monitored variable" (MD 181).
The minimum value is displayed in machine data "Display minimum value" (MD 182) and the
maximum value in machine data "Display maximum value" (MD 183).
0: Function deactivated
1: Function activated with absolute-value evaluation
2: Function activated with bipolar evaluation
Enable motor switchover 180
Default value Lower input limit Upper input limit Units
0000 0000 0001 Hex
Active
at once
Input for enabling of motor switchover (star-delta switchover). This machine data ensures a
wide range of constant power. At low speeds, the drive is operated with a star connection
(high torque) and at high speeds with a delta connection (high breakdown torque). The star-
delta switchover can take place when the motor is running.
The switchover is described in more detail below:
The PLC requests a star-delta switchover via a bit in the control word. As soon as the drive
has evaluated this control bit, the motor pulses are suppressed and an appropriate "pulse
suppression" signal sent to the PLC. Only after arrival of this signal may the PLC separate
motor contactor 1. The PLC must wait until motor contactor 1 is open before it reverses the
winding connection by closing motor contactor 2. At the same time, the motor data are
reloaded in the drive. Once motor contactor 2 is closed, the PLC signals to the drive that
contactor switchover has taken place. As soon as the drive has processed this signal, the
motor pulses are enabled (provided, of course, that all motor data have been reloaded), thus
completing the star-delta switchover operation.
0: Switchover disabled
1: Switchover enabled
Note:
A "Star-delta switchover" function block (FX 82) also exists. However, this may only be used
for digital main spindle drives (see Configuring Instructions, Function Blocks PLC 135
WB2/WD, Package 0: Basic functions).
Address for min/max memory 181
Default value Lower input limit Upper input limit Units
0D02 0000 FFFF Hex
Active
at once
Input of address for the variable to be monitored. The min/max memory is activated in MD 179.
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SINUMERIK 840C (IA)