Siemens SINAMICS G150 Operating Instructions Manual page 406

Setpoint channel and closed-loop control
7.4 Vector speed/torque control with/without encoder
Behavior for speed control without an encoder (p1300 = 20)
Depending on the transmission path of the external speed signal, dead times will occur;
these dead times must be taken into account in the speed controller's parameter assignment
(p1470, p1472) and can lead to corresponding losses in the dynamic performance.
Signal transmission times must therefore be minimized.
p1750.2 = 1 should be set so that the speed controller is also able to work at standstill
(closed-loop controlled operation to zero frequency for passive loads). Otherwise, at low
speeds it switches over to speed-controlled operation, so that the speed controller is
switched off and the measured actual speed no longer has an influence.
Monitoring of the speed deviation between motor model and external speed
The external actual speed (r1443) is compared with the actual speed of the motor model
(r2169). If the deviation is greater than the tolerance threshold set in p3236, after the switch-
off delay time set in p3238 expires, fault F07937 (Drive: Speed deviation motor model to
external speed) is generated and the drive switched-off corresponding to the set response
(factory setting: OFF2).
Figure 7-20
Function diagram
FP 6040
FP 8012
Parameter
• r0063[0]
• p1440
• p1443
• r2169
• r2199.7
• p3236
• p3237
• p3238
404
Monitoring "Speed deviation model / external in tolerance"
Vector control – speed controller with/without encoder
Signals and monitoring function – Torque messages, motor blocked/stalled
Actual speed value unsmoothed
CI: Speed controller actual speed value
CO: Actual speed value at speed controller actual speed value input
CO: Actual speed value smoothed messages
Speed deviation model / external in tolerance
Speed threshold 7
Hysteresis speed 7
Switch-off delay n_act_motor model = n_act_external
Converter cabinet units
Operating Instructions, 03/2012, A5E03263466A