7 Drive Machine Data (SIMODRIVE Drive MD) 10.94
7.1.2 MSD MD (data description - SW 3)
Rounding degree speed setpoint
19
Default value Lower input limit Upper input limit Units
0 0 30 –
Active
at once
Input of parameter setting for a PT2 filter (low-pass) in the speed setpoint channel. The low-
pass filter is inserted on the output side of the ramp-function generator and is effective only if
the speed setpoint smoothing function (MD 53, bit 4) is activated at the same time.
Diagnosis speed actual value
20
Default value Lower output limit Upper output limit Units
0000 0000 – 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 20 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
nmin for nact < nmin message motor 1
21
Default value Lower input limit Upper input limit Units
12 0 Rated speed rev/min
Active
at once
Input of response value for monitoring of the PLC status message nact < nmin (see also
MD 241).
Creep speed pulse suppression motor 1
22
Default value Lower input limit Upper input limit Units
Rated speed
––––––––––––––
256 0 Rated speed rev/min
Active
at once
Input of response value for the internal nmin sensor for stopping the drive with no reverse
rotation. When the speed nmin is reached, the drive torque is cut off and the drive coasts to a
stop with any remaining kinetic energy.
Note:
This nmin threshold is not the same as the response value of the nmin monitor, but it may be
set to the same value.
7–4 © Siemens AG 1992 All Rights Reserved 6FC5197- AA50
SINUMERIK 840C (IA)