Siemens SINUMERIK 840C - Manual (Page 564)

04.96 7 Drive Machine Data (SIMODRIVE Drive MD)
7.3.2 Drive MD (data description)
• Diagnostic function "Voltage-controlled V
q
operation" (up to SW 4)
A voltage-controlled operating mode (V/F mode) is applied in order to diagnose speed or
current sensor faults. In this operating mode, voltages V
q
and V
d
= 0 as well as a
frequency are input as controlled quantities. As a result of the transformation (d/q
R/S/T), a constantly changing rotating field is applied to the motor via the trigger
equipment ASIC, making it possible to attain a speed within the n
rated
/5 range in V/F
operation. The system oscillates at higher speeds.
Corresponding machine data are as follows:
– Motor frequency V/F mode (MD 1660)
– Ratio V/F during V/F mode (MD 1661)
• If MD 1661 is set to an excessively high value, the resulting I
d
current at n
rated
/5 causes a
temperature rise in the drive and an additional increase in oscillation at high speeds.
• If MD 1661 is set to a very low value, the resulting I
q
current value is too low, making it
impossible for the drive to follow the specified frequency.
• An operating status message is transmitted to the SERVO by means of bit 28 in the status
word.
• The current and speed controllers are not active in V/F mode
• Unfavourable parameter settings may cause excessively high currents to occur in V/F
mode; the existing current monitoring function therefore remains active.
Signal number min/max memory 1651
Default value Lower input limit Upper input limit Units
0 0 100 –
Active
at once
Input of signal number of memory location to be monitored by the min/max memory function.
Caution:
This machine data is relevant only for Siemens-internal purposes and must not be altered.
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 7–149
SINUMERIK 840C (IA)