sylo-plc-comms

Sylo package: PLC comms layer for Studio 5000/Logix — CIP (EtherNet/IP via ciplogix, vendored wheel) controller info + tag reads/writes, and OPC UA (asyncua) browse/read/write against the controller's OPC UA server. No Logix Designer SDK required.

Split out of sylo-allen-bradley on 2026-09-09. Sibling packages in this bundle:

• sylo-allen-bradley — Logix Designer SDK wrapper (.acd upload/download, L5X export/import). SDK not bundled.
• sylo-logicforge — L5X parse/IO-scaffold, Parse Rules UI, bundled LogicForge backend.

Tools

Tool	What it does
plc_comms_cip_plc_info	Full controller attributes (read-only CIP Identity)
plc_comms_cip_tag_list	Controller + program tag list (read-only)
plc_comms_cip_tag_read	Read one/many tags (pycomm3 syntax)
plc_comms_cip_tag_write	Write one/many tags — allowlist-gated
plc_comms_opcua_status	Probe the OPC UA server (endpoints, namespaces)
plc_comms_opcua_browse	Browse the address space (read-only)
plc_comms_opcua_tag_list	Recursive Tags-namespace listing (read-only)
plc_comms_opcua_read	Read nodes by node-id/tag path (read-only)
plc_comms_opcua_write	Write nodes — allowlist-gated

Allowlist

Writes (cip_tag_write, opcua_write) are gated by the same operator-managed download allowlist as project downloads. The canonical file lives in sylo-logicforge at packages/sylo-logicforge/assets/download-allowlist.json (this package's loader resolves it across the monorepo); env override: LOGICFORGE_DOWNLOAD_ALLOWLIST.

Python

ciplogix installs on demand from vendor/ciplogix/*.whl (committed); asyncua pip-installs on demand (see scripts/requirements.txt). Runs on the same SYLO_PYTHON as the other controls packages — no SDK Python needed.