09.95 12 Functional Descriptions
12.19.5 Interpolation and compensation with tables
12.19.5.1 Functional description
Possibilities with
• IKA
– 32 IKA configurations
– 32 IKA curves (SW 3)
– 16 000 IKA points (from SW 3)
65 535 IKA points (from SW 4)
– Scanning in IPO cycle
– Control of axis and actual values
– Changes to the input and output quantity value are active after Power On or warm restart
– Only axes can be defined as the input/output quantities
• IKA Stage 2
– Easily programmable
– Output influences axis setpoint/axis actual value
– Output influences channel or axis override
– Output influences R parameter (cascading)
– Intermediate point interpolation also cubic
– Tables can be retroloaded individually and activated for up to 65 535 IKA points
General
For the purpose of interpolation and compensation with tables (IKA), a maximum of 32 mutually
independent IKA configurations can be defined. These IKA configurations can all be operative
at the same time. This type of configuration defines the relationship between an output and
input quantities. Some of the 32 IKA configurations can be used to compensate machine
errors (sag, leadscrew error compensation, etc.) and the remaining configurations to implement
geometric profiles. The manufacturer should therefore reserve a number of IKA configurations
for machine compensation purposes; the others are then available to the user as workpiece-
defining and tool-dependent IKA configurations.
A table containing a sequence of curve points is assigned to each IKA configuration. A com-
pensatory/additional value of the output quantity can be entered against every interpolation
point value of the input quantity.
The intermediate points (e.g. actual positions of input quantity) can be entered at variable
distances and with variable compensatory values. If the IKA is to act as a leadscrew error
compensation (LEC), then the same axis is assigned to the input and output quantities.
If the input quantity is located between two interpolation points, then the compensatory/
additional value is calculated from the outer values according to the selected interpolation type
(linear or cubic). Each output value is calculated in an interpolation cycle.
To facilitate handling of IKA data for specific workpieces and tools, it can be stored under a
workpiece. When the workpiece is loaded, the appropriate IKA data are transferred to the NCK
at the same time. A warm start, which must be configured in the PLC, is required to activate
the newly loaded IKA data.
Depending on the scope of the function, the function is activated on a warm restart or
corresponding control functions (softkey/CL800 operation).
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50
12–193
SINUMERIK 840C (IA)