Running The Inverter; Stopping The Inverter - Siemens 6SE2101–1AA01 Operating Manual

7.5.1.2 Running the Inverter

Once SWITCH ON INHIBIT has been cleared the inverter may respond to run commands. The inverter will run
when the following conditions are satisfied:
AUTOMATION CONTROL (bit 10 PZD1) set to 1.
ON LEFT (bit 12 PZD1) or ON RIGHT (bit 11 PZD1) set to 1. Note that a 'failsafe' mechanism applies
here; one, and only one, of these bits must be set. Failure to do this will result in the inverter being
STOPPED.
INHIBIT RAMP (bit 4 PZD1) set to 1.
STOP RAMP GENERATOR (bit 5 PZD1) set to 1.
INHIBIT SETPOINT (bit 6 PZD1) set to 1.
OFF1 (bit 0 PZD1) set to 1.
OFF2 (bit 1 PZD1) set to 1.
OFF3 (bit 2 PZD1) set to 1.
ENABLE / INHIBIT OPERATION (bit 3 PZD1) set to 1.
FREQUENCY SETPOINT contained in PZD2. This is defined as a relative value by the USS protocol
whereby a value of 0000 hex corresponds with 0% demand, and a value of 4000 hex corresponds with
100% demand. On the 6SE21, this is interpreted as being a percentage of P08 (maximum frequency).
As an example, the value 0C7F hex in PZD1, together with the value 4000 hex in PZD2 will cause the inverter to run
to the frequency stored in P08 when transmitted.
The reply message will contain the actual output frequency – again as a percentage of P08 (in PZD2).
When the inverter is running, the reply bit OPERATION ENABLED (PZD1 bit 2) will be set to 1.
When the inverter output frequency is equal to or above the set–point, the reply bit SETPOINT REACHED (PZD1
bit 10) will be set to 1.
The reply message will have ON RIGHT (PZD1 bit 11) set to 1 if the inverter output is FORWARD. For REVERSE,
ON LEFT (PZD1 bit 12) will be set to 1.

7.5.1.3 Stopping the Inverter

The 6SE21 supports USS OFF1 and OFF2 commands, of which OFF2 has priority.
To stop the inverter via OFF1, set PZD1 bit 0 to 0. This will result in the inverter ramping down at the ramp rate
specified by P03.
To stop the inverter via OFF2, set PZD1 bit 1 to 0. This will result in the inverter output being disabled immediately
and the motor free–wheeling to a stop. The inverter will be put into SWITCH ON INHIBIT status after an OFF2 and
this will need to be cleared (see section 7.5.1.1) before the inverter will respond to a RUN command again.
OFF3 is not supported by the 6SE21 and if requested will return an error code (PKE bits 12 to 15 = '0 1 1 1', PWE =
101 decimal – 'Function not implemented').
ENABLE / INHIBIT OPERATION (bit 3 PZD1) will also cause the inverter to stop via OFF2 when set to 0 (inhibit
operation).
Reply messages always contain OFF2 AVAILABLE (PZD1 bit 4 set to 0 (available)) and OFF3 AVAILABLE (PZD1
bit 5 set to 1 (not available)).
7/10 English