NORD Drivesystems BU0050 - Manual (Page 27)

1.5 USS - Data transfer
BU 0050 GB-3111 Subject to technical amendments 27
1.5.2 PPO types
For cyclic data traffic, the Parameter- Process data Object (PPO) with which the process data (PZD) and
parameters (PKW) are transferred from the master to the frequency inverter is defined. The frequency
inverter can process PPO types 1, 2, 3 or 4.
Type Task
PPO1 extended parameter data telegram with 32 bit parameter values and process data
PPO2 Telegram with extended process data (main and two auxiliary setpoint values) and 32 bit parameter value
PPO3 Process data telegram with main setpoint value without parameter data
PPO4 extended process data telegram with main and auxiliary setpoint values without parameter data
PPO3 and PPO4 are purely process data objects for applications which do not require parameter
processing.
Abbreviations used:
PPO Parameter Process data Object STW Control word
PKW Parameter identifier Value ZSW Status word
PZD Process data SW1..3 Setpoints 1-3
PKE Parameter identifier IW1..3 Actual values 1-3
IND Index
PWE Parameter Value
Note:: An SPS can normally only consistently transfer double words by means of I/O memory access.
For longer data formats (PKW channel always / PZD data with PPO2 or PPO4) system functions
(e.g. SFC 14, consistent data reading / SFC15, consistent data writing) must be used.
NOTE
Because of the protocol specification, for PPO types 2 and 4 6 words must be reserved for
the address area of the process data (PZD). The two last words are not used for the process
data telegrams and are therefore merely reserve areas.