S2f15

S2F15/S2F16 is the SECS-II message pair the host uses to write new values into one or more Equipment Constants (ECIDs), the write counterpart to S2F13/S2F14's read-only request — this is how a host changes a tool's calibration offset, timeout, or mechanical limit rather than merely observing its current value. S2F15 (Equipment Constant Send) carries the ECID-value pairs the host wants to set; S2F16 (Equipment Constant Acknowledge) returns a status code per constant rather than a single pass/fail for the whole request, because equipment can legitimately accept some of the requested changes while rejecting others in the same message — a value out of the constant's valid range, or a constant that is currently locked by local operator action, are both reasons one specific ECID in the batch might be refused while the rest succeed.

The per-constant acknowledge structure is the detail that catches integrators who treat S2F16 the way they'd treat a simpler pass/fail acknowledge — a host that only checks "did S2F16 come back" without inspecting each individual status code can silently believe a batch of constant updates all succeeded when in fact one was quietly rejected, which is exactly the kind of mismatch between the host's assumed configuration and the tool's actual configuration that causes a process to run against the wrong calibration value without anyone noticing until a wafer comes out wrong. Any production integration writing equipment constants through S2F15 should treat the per-ECID result as the authoritative outcome, not the mere presence of a reply.

S2F15/S2F16 is the write half of equipment-constant management, with S2F13/S2F14 as its read counterpart, and both pairs ultimately operate on the exact ECIDs a tool's Common Equipment Model (SEMI E120) already documents — writing a constant that isn't in the model, or writing one with the wrong data type, is exactly the kind of mismatch CEM's machine-readable documentation exists to prevent before it ever reaches a live S2F15 request.