Siemens SIMATIC TIWAY 1 - Manual (Page 171)

ERROR CODES AND DIAGNOSTICS
UNILINK HOST ADAPTER 6–8
USER MANUAL
8017 This macro is disabled because the host issued a disconnect to its HIU
and an exception occurred prior to the disconnect.
8020 The macro response was too large to fit into the buffer.
8021 The wrong secondary address was in the macro response.
8023 Received the wrong TIWAY I Primitive in the link action response. The
secondary device should have returned a response for either Primitive
20 or Primitive A0.
8024 Received the wrong TIWAY I Primitive in the link trigger response. The
secondary device should have returned a response for either Primitive
30 or Primitive B0.