When testing a passive-contact membrane-key input, High Z in a signal generator's load menu does not mean an open contact or a passive output. Check what the menu means in that instrument's manual, then use the host-board interface documentation to establish an acceptable test stimulus. Even if the board recognizes an injected waveform, that result covers only the input test performed. It does not replace verification of the real key's press and release. This article covers ordinary, non-safety inputs, not live wiring procedures.
On November 10, 2026, Pickering Interfaces announced PXI/PXIe arbitrary waveform generators, listing multi-channel sensor simulation and automated test equipment upgrades among their applications. The release does not describe membrane-switch wiring or any Baoshengda supply relationship. For a separate equipment project planning to reproduce key pulses with a waveform source, a practical question comes first: does selecting High Z make the source equivalent to an ordinary pushbutton contact? What the source outputs and whether the real key opens and closes correctly need separate records.
In this documentation, High Z is a load setting
Keysight BenchVue's Output Load Termination help states that most supported function generators have a fixed 50-ohm series output impedance. If the actual load differs from the setting, the displayed amplitude and offset will be incorrect. Changing the load setting to high impedance adjusts the displayed values. This describes the assumed load and voltage display; it does not say the output becomes an open switch contact. Check the manual for the actual model. Do not apply this explanation directly to the modules in the news release or to every other source.
Here, High Z means this type of instrument's load-menu setting, not a GPIO tristate mode. A passive-contact membrane switch opens and closes an agreed circuit; the host-board design determines how that circuit is excited and read. For terminal directions and power boundaries, see the membrane-switch GPIO interface guide. A menu label alone does not establish that two devices can be connected directly.
| Setting or result observed | What to check | Limit of the conclusion |
|---|---|---|
| High Z selected in the generator's load menu | The model's load definition, amplitude and offset display rules, and the actual receiving load | An instrument configuration, not an open contact or proof of an isolated output. |
| The host board recognizes a test waveform | The waveform measured at the approved test point, board hardware and program versions, and the input conditions covered | Record recognition under those stimulus conditions. Do not mark the membrane switch as accepted. |
| A real key is pressed, held and released | The actual switch, assembly, circuit and host-board readings | Record each result against the project requirements. Do not infer contact behavior, feel or service life from a generator test. |
Link the board-input test to the real-key record
The table is an engineering review aid based on the instrument documentation and component roles, not a universal wiring table. Before testing, the equipment's electrical lead should confirm the permitted input conditions, reference connections, isolation and protection, approved stimulus method and measurement points. Leave missing definitions open; do not connect equipment on the strength of the words High Z. Emergency stops, safety interlocks and commissioning hazardous equipment are outside this article's scope.
- Save the generator model, applicable manual, load-menu setting, amplitude and offset, and measurement-end settings. Record the actual waveform at the approved test point, not just the generator's displayed values.
- State whether the test checks board-input recognition alone or includes the membrane switch. If the real key is absent, mark the result “test-source stimulus; real contacts not covered.” For short-pulse sampling and filtering, see the missed short-press recording guide (Chinese).
- Then check the matching real key and assembly under the approved plan, with separate press, hold and release records. Link both sets of records through the sample ID, interface drawing and board version. Do not copy the same “normal response” into both conclusions.
Shenzhen Baoshengda Technology Co., Ltd.'s membrane-switch customization page (Chinese) calls for circuits and flexible tails to be checked against the host-board interface, with matching drawings and fitted samples used to confirm supply requirements. See also the English product page. This supports component customization discussions, not an included active test interface or whole-machine debugging service. A graphic overlay or keypad overlay supplied alone has no switch circuitry; an overlay with metal domes that works with the customer's PCB needs the customer board and readout circuit listed separately. The cover shows keypads with flexible connections, not proof of their pin assignments, impedance or test results.
Use the project contact page to share circuit drawings, interface definitions and sample photos that you are allowed to disclose. Specify whether you need to confirm component continuity or the board's recognition of a defined stimulus. Attach the source model and real-key records separately, with missing items clearly identified.