NORD Drivesystems BU0220 - Manual (Page 68)

PROFIBUS DP – Supplementary manualfor NORD Frequency Inverter SK 2xxE
68 Subject to technical amendments BU 0220 GB-0912
7.2.3 Parameter area (Parameter code value PKW)
Using the PKW mechanism, parameter processing can be carried out in the cyclical data traffic. For this the
master formulates an order and the inverter formulates the appropriate response to this. The parameter area is
only used for transfer with PPO type 1 and PPO type 2.
In principle, the parameter range consists of a parameter identification, in which the type of order (Write,
Read etc.) and the relevant parameters are specified. Individual parameter sets or array elements can be
addressed with the aid of the Index. The parameter value contains the value to be written or read.
Note: A parameter order must be repeated until the inverter responds with the corresponding response
telegram.
ATTENTION
If parameter changes are made (i.e. requests via the PKW area by the control master), care
must be taken that the maximum number of permissible writing cycles to the frequency
inverter EEPROM (100,000 cycles) is not exceeded. I.e. continuous cyclical writing must be
prevented.
For certain applications it is sufficient if the values are only saved in the RAM memory of the
frequency inverter. The corresponding setting is made via parameter (P560) "Save in
EEPROM".
7.2.3.1 Parameter label (PKE)
The order or response and the associated parameters are encrypted in the parameter label (PKE).
1 2 3 4
PKE IND PWE1 PWE2
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
SPM
AK PNU
The parameter label (PKE) is always a 16 bit value. This is divided into the following areas:
PNU: Bits 0 to 10 contain the number of the required parameter (PNU), or the number of the current
parameter in the response telegram of the frequency inverter.
The parameter numbers (PNU) for the particular frequency inverter series can be found in the
relevant frequency inverter manual.
SPM: Bit 11 is the toggle-bit for spontaneous messages. This function is not supported!
AK: Bits 12 to 15 contain the order or response label.
NOTE
With the PROFIBUS DP protocol, the inverter parameters are mapped in the range from
1000 to 1999 i.e. for parameterisation via the bus, 1000 must be added to the parameter
numbers (e.g. P508

PNU=1508).
Both the order label and the response label are abbreviated as AK. Therefore, care must be
taken when reading or interpreting the order processing description in this section.