CipConnection gains two process-wide gate-diagnostic counters next to ForwardOpenCount: ForwardClosesSent (incremented as the request goes on the wire) and ForwardClosesAcked (incremented when the reply arrives within the 1 s budget).
It also records round-trip statistics for completed exchanges: ResetExchangeStats() clears them and ReadExchangeStats() returns count, min, max and mean. The cost is two Stopwatch reads and a few interlocked operations per request. No behaviour changes.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
The T21 press pass 1 test host died at exit with "A callback was made on a garbage
collected delegate of type ...plctag+callback_func_ex::Invoke". The cause is in
libplctag.NET 1.5.2. When a tag's create fails, for example with NotFound,
InitializeAsync throws with the callback still registered. Dispose() destroys a tag
only if it is initialised, so the native tag outlives its wrapper. The GC then frees
the delegate, and libplctag's atexit plc_tag_shutdown raises DESTROYED into it.
Reproduced against ab_server: the production LibplctagTagRuntime with a NotFound tag
exits 134 with that exact message, and exits 0 with this fix.
A timed-out create unregisters its callback but never destroys the handle either,
so that native tag keeps reconnecting for the life of the process.
The fix adds LibplctagOrphanRelease (AbCip and AbLegacy). After a failed
initialise/read/write that leaves the tag uninitialised, it reads the handle through
the pinned wrapper's private fields, unregisters the callback and destroys the tag.
If those fields cannot be read, it roots the tag for the life of the process
instead. It is applied in both tag runtimes, the symbol-listing reader and the
template reader. GetStatus keeps the status the tag held before it was destroyed.
Pins: offline refused-connection tests in AbCip.Tests and AbLegacy.Tests, a live
NotFound test on ab_server, and a reflection-shape pin. All go red with the release
disabled. The differential harness also asserts that no orphan had to be rooted.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
- AbCip/AbLegacy driver forms gain a Transport InputSelect; FromOptions/ToOptions now carry
Transport, so saving any other field no longer silently reverts Native to libplctag.
- Both drivers log the constructed transport once per init.
- AbCip factory now takes the host ILoggerFactory (it ran on NullLogger in production, hiding
every AbCip log line); DriverFactoryBootstrap passes it.
- Gate results: AdminUI /run (T19) native, inverted (dead port) and libplctag legs.
The libplctag adapters assigned Tag.Path straight from the device's parsed
CipPath. A device address with no route (ab://host:44818/ - the normal
Micro800 form, and a MicroLogix with no route) parses to "", and libplctag
rejects an empty path attribute with ErrorBadData; omitting the attribute
(null) is what it accepts. So Micro800 could not connect on the default
libplctag transport.
This predates the native transport work and exists on master.
Add an internal LibplctagPath.Normalize helper per driver project (blank ->
null) and route all four Tag constructions through it (AbCip tag runtime,
symbol-list enumerator, template reader; AbLegacy tag runtime). The runtime
tag construction is extracted to an internal BuildTag so tests can inspect
Tag.Path without connecting. Tests fail with Normalize reverted to identity.
Update the Micro800 smoke-test comment: both transports are expected to pass.
ab_server answers every Execute PCCC with a fixed requestor id (pccc.c
PCCC_RESP_PREFIX: 07 3D F3 45 43 50 21) instead of echoing the request's, so
the R14-3 echo check rejected every native reply sent under the 0x1337 CIP
originator identity as BadReply. The pooled runtime now sends libplctag's
identity (PcccServices.RequestorVendor/RequestorSerial), which passes the echo
check against ab_server and against a real controller that echoes. Pinned by a
FakeEipServer round trip that answers with ab_server's fixed prefix.
ab_server's RegisterSession sanity check rejects any non-zero sender context
with encapsulation status 1 and a header-only reply, so every native session
against the simulator failed with BadCommunicationError. libplctag sends zero
(logix-register-session.hex); the codec test now matches that capture byte for
byte instead of excluding the context, and a client test pins the zero on the wire.
Found by the read-only live gate against the TwinCAT 2.11 Elma cleaners
Z33856 / Z33733:
- The Beckhoff library reports a TC2 dotted MEMBER symbol's ByteSize as if the
PLC's byte count were a bit count (STRING(80) -> 11, INT -> 1, UDINT -> 1)
while DataType.ByteSize is right (81/2/4, raw SYM_INFOBYNAMEEX says 81). The
previous commit's typeof(byte[]) read sliced by the symbol size, so
.OPC_MACHINEDATA.PROCESSSTATUS read "ready for o" at Good; the notification
width check would also have refused every numeric member. The shape now takes
the resolved type's size, and string reads go by index group/offset (or a
fresh handle for 0xF005) at that width.
- P_INITINPUT_ACTION.SLOTID is "STRING(20) (VAR_IN_OUT)" - a 4-byte reference -
but resolves to a plain STRING(20); a String tag read 21 bytes at the pointer
as text at Good. The symbol's own VAR_IN_OUT marker now classifies it
NonScalar -> BadTypeMismatch.
libplctag decodes whatever bytes the controller returns as the authored type and never
checks the CIP type code. Live read-only check on a production press: WW_ActualVacuum is a
REAL (L5X + the controller's symbol table agree) but the legacy Kepware export in the
ignitionoee repo types it Short; read as INT it returned Good -17346 while the real value
was 5.37. A scalar atomic read (not an array, not a bit-in-DINT) whose buffer size is not
the authored type's width now reads BadTypeMismatch with a warning naming both. Widths
observed live: SINT/BOOL 1, INT 2, DINT/REAL 4, LINT 8. IAbCipTagRuntime.GetSize() is a
default-interface member (-1 = unknown, never checked). Same-width mismatches (DINT vs
REAL) stay undetectable without the type code libplctag strips.
Live read-only check against a production CompactLogix press: Program:UN01_Press._ModeNames
(STR0016[32], 4 elements requested) returned an 80-byte buffer with libplctag.NET 1.5.2's
ElementSize unset. The driver fell back to the static 88-byte STRING stride, read element
1 past the buffer, and the whole read failed (ErrorOutOfBounds -> BadCommunicationError).
When the buffer divides evenly by the element count, that quotient is now the stride;
the read returns [undefined, Production, Maintenance, Manual] as the controller holds.
Live read-only check against a production CompactLogix press: with one nonexistent tag
first in the read list, libplctag's create threw LibPlcTagException("ErrorNotFound"); the
driver counted it as a failed Forward-Open, opened the device's 05/STAB-8 connect-backoff
window, and every other cold tag on the device - all real (WW_InCycle, WW_ActualPress,
WW_WorkOrderNum) - read BadCommunicationError. In steady polling the bad tag re-opens
the window each attempt, so siblings ordered after it may never connect.
- A create that fails with a "controller answered" status (NotFound/NoMatch/BadDevice,
the probe's existing reachable classification) records backoff SUCCESS, not failure.
Genuine connection failures still open the window (falsification control test).
- Read exceptions map through the libplctag Status they carry: unknown tag ->
BadNodeIdUnknown, decode past the buffer -> BadOutOfRange, timeout -> BadTimeout,
instead of a blanket BadCommunicationError. One status-name parser
(AbCipStatusMapper.TryGetStatus) now serves both the read path and the probe.
WireFocasClient.GetProgramInfoAsync defaulted every field the CNC did not report:
ONumber ?? 0 when the cnc_exeprgname2 payload was too short to carry it, and
Name '' / BlockCount 0 / Mode 0 when the sub-read was refused. 0 is a genuine
O-number (a 31i reports 0 for a path-executed program -- live Z-34184), a
genuine block count, and Mode 0 is MDI, a real operating mode.
FocasProgramInfo fields are now nullable; MapProgramInfo leaves unreported
fields null and the fixed tree publishes them BadNoData while the bundle's
other fields stay Good.
Ported from the sister ignitionoee FOCAS driver (101a3b1, 2026-08-12).
Live read-only check: a production CompactLogix lists the module tag ABB_OmniCore:I in
@tags and libplctag reads ABB_OmniCore:I.ConnectionFaulted without complaint, but the
driver refused the path as malformed (identifier rule had no colon) and reported the
tag BadCommunicationError. Colon-separated identifier/slot parts are now legal in the
controller-scope base segment only (never past it, never under Program: scope).
Servo (0x0056) and spindle (0x0040) meter records are 8 bytes:
[i32 value][u16 base][u16 exponent], the same self-describing envelope as the
position blocks.
Servo: offset 4 was read as a decimal count. It is the BASE (a steady 10), so
every load was divided by 10^10 and published ~0 -- the sister ignitionoee panel
read servo 0% on every axis of a Makino cutting at 20,000 rpm. Loads are now
value / base^exponent, a direct percentage.
Spindle: the raw meter is a 1/16384 fraction of full scale. Settled on the real
Z-34184 by regressing the type-1 meter against cnc_rddynamic2 spindle speed over
596..20,000 rpm (rpm = 1.220749 x meter; 16384 x 1.220749 = 20000.75). So:
- Spindle/{name}/Load publishes % of rated load (Float64; was the raw Int32
count -- a reading of 9155 meant 55.9%).
- Spindle/{name}/MaxRpm is RENAMED Spindle/{name}/MotorSpeedPct (Float64, % of
maximum speed) and is polled with Load. The old node was actively wrong: the
type-1 meter is the live motor speed, and it was read once at bootstrap and
served forever as if it were a max-RPM constant. Client-visible: FIXED: tags
on .../MaxRpm must be re-pointed.
- The spindle read no longer stops at the first zero after slot 1 (which dropped
an idle second spindle and kept non-zero residue); every slot is returned.
A record whose envelope is undescribable (base not 2/10, exponent > 18 -- e.g.
residue past the configured axis/spindle count) publishes BadNoData, never a Good 0.
Ported from the sister ignitionoee FOCAS driver v0.17.2/v0.17.3 (Focas.Wire-019);
live captures live-spmeter-{load,maxrpm}-0x0040.bin added as fixtures.
Live read-only check against production CompactLogix 5069-L320ERS2 presses:
- The controller @tags listing names each program (Program:UN01_Press, a system symbol)
but none of its tags; those are listed only by Program:<name>.@tags. The enumerator read
@tags alone, so every program-scoped tag was unbrowseable — including the PackML state
(Program:UN01_Press.Out_eState) and all 51 alarm bits the Ignition project reads. The
enumerator now reads each program's listing and decodes it with that program as scope;
an unreadable program listing is skipped, not fatal.
- The Symbol Object decoder ignored the dimension bits + dim words, so every discovered
array (DINT[32], REAL[32], STRING[50], UDT[23] on the two controllers checked) browsed as
a scalar. IsArray/ElementCount are now populated (multi-dim flattened). A 1-D single
element entry stays scalar: ab_server reports every scalar that way, a real controller
sets no dimension bits on scalars.
Pinned by entries captured off the controllers (CipSymbolObjectRealControllerCaptureTests,
AbCipProgramScopeEnumerationTests).
Joseph Doherty