Siemens SINUMERIK 840C - Manual (Page 575)

7 Drive Machine Data (SIMODRIVE Drive MD) 07.97
7.3.2 Drive MD (data description)
Current actual value (effective) (as from SW 6) 1719
Default value Lower output limit Upper output limit Units
– – – A
eff
Active
at once
Current actual value display. The signal can be output via DAC.
MD 1719 = i 2
qact
+ i 2
dact
CRC diagnosis parameter 1720
Default value Lower output limit Upper output limit Units
0000 0000 FFFF Hex
Active
at once
This machine data displays the CRC (cyclic redundancy check) errors which have been
detected. The counter information is output on every read request and is 5 bits in width
(bit 4...bit 0 or counter content 0...31).
Note:
It cannot always be assured that the CRC errors are assigned to the appropriate drives. With
an incorrect address, the "wrong" module indicates the error (if present).
Diagnosis speed actual value 1721
Default value Lower output limit Upper output limit Units
0000 0000 FFFF Hex
Active
at once
Display of the monitoring machine data "Diagnosis speed actual value". If an impermissibly
large speed deviation occurs within the sampling period, then the value of the machine data is
incremented. Sporadic responses by a few increments can be ignored since these do not
influence the speed controller. A high disturbance level will cause the contents of MD 1721 to
be increased repeatedly by several increments.
Possible causes of disturbances:
• Encoder shield not earthed
• Encoder defective
• Earth connection of electronics ground in MSD module faulty
• Motor earth not connected in MSD module
• Value entered for motor moment of inertia too high
• Evaluation electronics
Note:
The function is activated with MD 1610, bit 0, and the threshold entered in MD 1611.
Capacity utilization 1722
Default value Lower output limit Upper output limit Units
0 -100000.0 100000.0 %
Active
at once
Display machine data for utilization of drive capacity. The display shows the ratio "torque
setpoint M
d
to present torque limit M
dmax.
" Values lower than 100% indicate system reserves.
Smoothing to obtain a steadier display of the signal can be set in MD 1251, time constant
motor load.
7–160 © Siemens AG 1992 All Rights Reserved 6FC5197- AA50
SINUMERIK 840C (IA)