NORD Drivesystems BU0940 - Manual (Page 23)

3 Process modules
BU 0940 GB-3612 23
3. Process modules
Process modules are only used to control a frequency inverter. No parameters are changed.
Parameter changes are only performed by the use of other measures. If parameter values from the
Step 7 program are to be changed, the appropriate parameter modules must be used. Call-up of the
process modules is carried out in the cyclic program.
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3.1 Purpose of the process modules
The function modules "Prozess_PPO…" are called up in the cyclic section of the program. In addition
to the process modules, the associated instance modules "Inst_PPO" are also required.
Example:
Function module: Prozess_PPO1_16
Instance data module: Inst_PPO1_16
Purpose:
The function module "Prozess_PPO…" is used to control a frequency inverter with up to three setpoint
inputs (Setpoint SW / Actual value IW). According to the type, up to three 16 bit setpoint inputs or one
32 bit and a 16 bit setpoint input (for positioning tasks with a 32 position setpoint) can be controlled on
the inverter. In this case, the resulting actual values correspond to a 32 bit value as Actual Value 1
(AV_1) and a 16 bit value as Actual Value 2 (AV_2).
In addition to supplying the module with the corresponding number of 32 bit setpoints (in real format),
the module also processes control tasks (Control word STW / Status word ZSW) such as error
acknowledgement and enable signals. The description of the inputs and outputs is summarised in
Section 3.3.
Function module Instance module Number of 32 bit
input values
Number of 16 bit
output values as
setpoint for FI
Number of 32 bit
output values as
setpoint for FI
Prozess_PPO1_16 Inst_PPO1_16 1 1 0
Prozess_PPO2_16 Inst_PPO2_16 3 3 0
Prozess_PPO3_16 Inst_PPO3_16 1 1 0
Prozess_PPO4_16 Inst_PPO4_16 3 3 0
Prozess_PPO2_32 Inst_PPO2_32 2 1 1
Prozess_PPO4_32 Inst_PPO4_32 2 1 1
Table 3: Assignment of function modules
The process modules
Prozess_PPO1_16 and Prozess_PPO3_16
Prozess_PPO2_16 and Prozess_PPO4_16
Prozess_PPO2_32 and Prozess_PPO4_32
are more or less identical. The difference between them is only the provision of an extended data
range of 4 words for the parameter identification data PKW for the PPO types 1 and 2.