Siemens SINAMICS V20 - Page 5

1 Task
1.2 Operation of the drive
SINAMICS V20 at S7-1200/1500 via USS
Entry ID: 109480894, V1.0, 09/2018
5
 Siemens AG 2018 All rights reserved
Control
The SINAMICS V20 drive is to be controlled via the following bit signals of the
control word (STW):
 ON/OFF1 – start bit of the SINAMICS V20 (STW1, bit 0)
If this parameter has the value TRUE, this input enables operation of the V20
at the preset speed.
 OFF2 – coast down to a standstill (STW1, bit 1)
If this parameter has the value FALSE, this bit causes the SINAMICS V20 to
coast down to a standstill, without braking.
 OFF3 – fast stop bit (STW1, bit 2)
If this parameter has the value FALSE, this bit causes a fast stop by braking
the SINAMICS V20.
 Fault ack. – error acknowledgment bit (STW1, bit 7)
With this bit, you reset the error bit of the SINAMICS V20 once you have
eliminated the drive fault. This informs the drive that it is no longer necessary
to signal the fault.
 Reverse – direction control of the SINAMICS V20 (STW1, bit 11)
This bit has to be set for clockwise rotation (provided that the speed setpoint is
positive).
Entering the speed
Speed setpoint (HSW)
This is the speed setpoint of the SINAMICS V20 as a percentage of the configured
frequency. When entering a positive value, the motor rotates clockwise if Reverse
has the value TRUE.
Status evaluation
The SINAMICS V20 drive is to continuously transfer the following bit signals of the
status word (STW) to the controller:
 Inverter running – operation enabled (ZSW1, bit 2)
This bit signals whether the SINAMICS V20 is running.
 Motor runs right – drive direction (ZSW1, bit 14)
This bit signals clockwise rotation of the motor.
 ON inhibit active – SINAMICS V20 inhibit (ZSW1, bit 6)
This bit signals the status of the inhibit bit for the SINAMICS V20.
 Inverter fault active – drive fault (ZSW1, bit 3)
This bit signals that a fault has occurred in the SINAMICS V20. The user has to
eliminate the fault and set the acknowledgment bit (STW1, bit 7) to delete this
bit.
Transferring the actual speed
Actual speed (HIW)
This is the actual speed of the SINAMICS V20 as a percentage of the configured
frequency. When the value is positive, the motor rotates clockwise if Motor runs
right has the value TRUE.
Display of communication errors
In the event of a communication error, the error status of the USS
®
system
instructions of the STEP 7 program is to be displayed.