Easiest answer is that Plamya use different program codes, for the different tasks.
(manual page 17)
Plamja-KV CVM (digital computer)
The digital computer has a 16bit processor, running at 64kHz frequency.
It has 256 bytes of RAM, and 4,096 bytes of ROM.
It has five built-in programs:
1. Idle
In this mode, the Plamja-KV is calculating the firing solution using the instantaneously available data from the RPC.
2. IADS target acquisition
In this mode, the Plamja-KV is interpolating the target's predicted position, between the 10Hz updates received from the IADS information.
3. Target tracking
In this mode, the Plamja-KV is continuously calculating the target's predicted path, and figuring the firing solution based on this information.
4. Tracking Jamming Target
In this mode, the Plamja-KV is calculating the firing solution using a manually preset target range. This mode is called AS-2.
5. Self Test