diff --git a/docs/developer/ptouch_label_printer_plan.md b/docs/developer/ptouch_label_printer_plan.md new file mode 100644 index 0000000..134628a --- /dev/null +++ b/docs/developer/ptouch_label_printer_plan.md @@ -0,0 +1,166 @@ +# Brother P-touch PT-P950NW label printing for BEC: design plan + +> **Status: proposal, not yet implemented.** This document captures the plan +> from an initial feasibility/design session so it isn't lost; it should be +> updated (or removed / folded into an architecture note) once the feature is +> actually built. + +## Context + +When a measured sample is unloaded from the flomni sample tray, the only record +of "who owns it / when it was measured" today is digital (tray-slot metadata +in `dev.flomni_samples`, plus the OMNY sample database via `TomoIDManager`). +There is no physical label on the actual sample holder, so a user picking it +up later has no way to tell at a glance whose sample it is or when it was +run. The goal of this feature is to print a small paper label (account + +date, on TZ tape) at the moment a measured sample is stowed back in the tray, +so it can be stuck straight onto the sample holder. + +This is explicitly **not** an experiment hardware component (no motion, no +staging, nothing that needs to be part of a scan) — it's a side-effect +utility, similar in spirit to the existing `TomoIDManager` (HTTP registration +call) and `HttpUploader` (webpage push) helpers, which are plain Python +classes invoked from the flomni/lamni plugin code at well-defined workflow +points, not ophyd devices. + +**Decisions already made:** +- Protocol: **P-touch Template mode** (Brother's official, documented + command protocol) rather than the raster/reverse-engineered protocol used + by third-party libraries like `rasterprynt`. This avoids needing an image + library (Pillow) client-side and avoids depending on an undocumented + protocol that could break on a firmware update — fits the goal of + minimizing external packages. +- Scope: build as a **shared utility** in + `bec_ipython_client/plugins/OMNY_shared/`, so lamni/omny can adopt it later + without duplicating printer/network code — mirrors where `TomoIDManager` + and `HttpUploader` already live. +- Trigger: **both**. Automatic prompt-then-print on sample unmount in flomni, + plus a manual/standalone command for on-demand (re-)printing. + +## How P-touch Template mode works (research summary) + +- The PT-P950NW supports raw network printing on **TCP port 9100** (listed + in its spec sheet alongside LPR/IPP/mDNS etc.), the same "JetDirect-style" + raw port most network printers use — no CUPS/driver install needed. +- "P-touch Template" is a printer-side mode built for exactly this use case + (the manual explicitly lists "data from a scale, testing machine, + controller, or PLC" as the target): you design a label layout **once** in + Brother's Windows-only **P-touch Editor** (place named text objects, e.g. + `ACCOUNT`, `DATE`), transfer that template onto the printer's internal + memory (via Editor's Transfer Manager over USB or network), and from then + on printing is just: connect to the printer, send a short **ESC i X** + command sequence selecting the template number and supplying the text for + each named field, then a print-start command. +- The command set is documented in Brother's "P-touch Template Command + Reference" (per-printer-family PDF from Brother's support site — confirm + the PT-P900W/P950NW-specific revision before implementing, since control + codes can differ slightly between printer families/firmware generations). +- No actively-maintained Python package implements this specific protocol + (unlike raster printing, which has `rasterprynt`/`brother_ql`-style + libraries). That's fine here: the runtime protocol is just building a byte + string and pushing it over a `socket` — stdlib only, no new dependency. + +## Implementation plan + +### 1. New shared module: `PTouchLabelPrinter` + +File: `csaxs_bec/bec_ipython_client/plugins/OMNY_shared/ptouch_printer.py` +(new file, alongside `omny_general_tools.py`/`web_common.py`). + +```python +class PTouchLabelPrinter: + """Prints a label on a Brother PT-P950NW via P-touch Template mode.""" + + DEFAULT_PORT = 9100 + + def __init__(self, host: str, template_number: int = 1, port: int = DEFAULT_PORT, timeout: float = 3.0): + ... + + def print_label(self, fields: dict[str, str], copies: int = 1) -> bool: + """Build the P-touch Template command for `fields` and send it. + + Returns True on success, False on any network/printer error -- + never raises, matching TomoIDManager's fail-soft convention so a + printer being offline can never block a sample transfer. + """ + ... +``` + +- Builds the ESC-prefixed command sequence (select template mode, select + template number, set each named field's text, set copy count, print + command) as pure bytes, opens a short-lived `socket.create_connection((host, + port), timeout=timeout)`, sends, closes. +- Wrap all I/O in `try/except`, `logger.warning(...)` on failure, return + `False` — same fail-soft style as `TomoIDManager.register()` + (`omny_general_tools.py:396-`) and `HttpUploader` (`web_common.py:48-114`). +- Printer host/IP and template number are constructor args (not hardcoded + constants), passed in from each plugin's config — check how other + beamline-specific endpoints are configured in this repo (e.g. is there a + per-instrument config file, or are they class constants like + `TomoIDManager.OMNY_URL`?) and follow that convention when wiring it up. + +### 2. Wire into flomni + +File: `csaxs_bec/bec_ipython_client/plugins/flomni/flomni.py` + +- Instantiate once in `__init__`, next to `self.OMNYTools = OMNYTools(...)` + (line ~1654) and `self.tomo_id_manager = TomoIDManager()`: + `self.label_printer = PTouchLabelPrinter(host=, ...)`. +- **Automatic path**: in the unmount branch of `ftransfer_sample_change` + (the `new_sample_position == -1` case, `flomni.py:867-906`) or in + `ftransfer_get_sample` (`flomni.py:734`, name/owner already unpacked at + line 786-787 as `name, owner = unpack_desc(signal_name.get())`), after the + stow completes: ask `self.OMNYTools.yesno("Print a label for this sample?", + "y")` (same helper already used elsewhere, e.g. `flomni.py:2507`) and on + `True` call `self.label_printer.print_label({"ACCOUNT": owner, "DATE": + str(datetime.date.today())})`. +- **Manual path**: add a small method, e.g. `fprint_sample_label(position: + int)`, that reads name/owner via the same `unpack_desc(...)` pattern as + `sample_get_name` (`flomni.py:853`) and calls `label_printer.print_label` + directly — usable standalone for reprints, without going through a + transfer. + +### 3. Open items to resolve before/during implementation + +- **No date is currently stored per sample slot** — `pack_desc`/`unpack_desc` + (`devices/omny/sample_desc_codec.py:19,40`) only carry `(name, owner)`, no + timestamp. Using `datetime.date.today()` at unmount time is a reasonable + v1 approximation (unmount typically happens same-day as the scan), but if + an exact measurement date is wanted later, the DESC codec would need a + third field. +- **Confirm the exact model-specific command reference.** Brother publishes + a separate "P-touch Template Command Reference" per printer family; + download the PT-P900W/P950NW-specific PDF from Brother's support site + before writing the byte-level command builder. +- **Template design is a one-time, Windows-only step** (P-touch Editor + + Transfer Manager) — not scriptable from the Linux beamline control host. + Worth doing once per label layout/TZ tape width; layout changes require + redoing this step. +- **Network reachability**: confirm the printer's IP is reachable from + wherever `bec_ipython_client` runs (same VLAN/firewall rules as other + network endpoints it already calls, e.g. the OMNY/tomo-ID server) and + assign it a static/reserved IP. +- Extend to lamni/omny by instantiating `PTouchLabelPrinter` in those + plugins too once flomni is validated — no code changes needed to the + shared module itself. + +## Verification + +1. **Bench test the printer/template alone**: install the PT-P950NW on the + beamline network with a fixed IP, design the label template once in + P-touch Editor (fields `ACCOUNT`/`DATE`, chosen TZ tape width), load it + via Transfer Manager, and print a manual test label from the desktop app + to confirm the template renders as expected. +2. **Bench test the protocol module standalone**: write + `PTouchLabelPrinter`, then from a scratch script call + `print_label({"ACCOUNT": "e12345", "DATE": "2026-07-31"})` against the + real printer IP and confirm a correct physical label comes out (check + encoding, field placement, tape length/cut). +3. **Integration test in flomni**: in a real or simulated + `bec_ipython_client` session, run `ftransfer_sample_change(-1)` (or + `ftransfer_get_sample`) end-to-end, confirm the yes/no prompt appears, + confirm printing on "y", confirm declining or a deliberately-unreachable + printer IP does **not** raise or block the sample transfer (only logs a + warning). +4. Test the manual `fprint_sample_label(position)` command independently of + any transfer, for reprints.