A rotary control panel switch that operators turn to change machine modes (manual / auto / stop, Run / Off / Auto and so on). The model on this page is the arrow type (clearer visual indication); other styles such as the round-knob type are available on request. 2-position, 3-position, spring-return and maintained versions are available, with standard Φ22 / Φ25 mounting. For SMT, EMS and semiconductor machine control panels.
A selector switch is one of the core “human-machine interface” components on a control panel. Unlike a push button (one press triggers an action), a selector switch is rotary — the operator turns the knob to different positions to change the machine mode (such as “manual / stop / auto” in 3 positions). The advantage is that the operator can see the current mode from the knob position alone, without a separate indicator lamp.
The model on this page is the arrow type (clearer visual indication); other styles such as the round-knob type are available on request. An arrow-type knob is shaped like an arrow (a long bar with a pointed end), so operators can see its position clearly from a distance with less risk of misreading — suited to large machine control panels and safety-related mode selection. Φ22 is the international mainstream (OMRON A22N, Fuji Electric and Schneider XB4/XB5 all use it), while Φ25 is another cutout size — confirm before buying. A JIAHON affiliated company supplies customers throughout Taiwan.
Specifications (reference for industry-standard rotary selector switches)
| Item | Specification | Note |
|---|---|---|
| Type | Rotary (round knob / arrow knob) | The model on this page is arrow type; other styles on request |
| Positions | 2 (ON/OFF) / 3 (left / center / right) | 3 positions is common |
| Action | Maintained (80%) / spring return (momentary) | Maintained is mainstream |
| Panel cutout | Φ22 (international mainstream) / Φ25 | Φ22 recommended for new lines |
| Contacts | 1NO / 1NC / 1NO+1NC / 2NO+2NC etc. | Choose by switching logic |
| Contact rating | Typically AC 240 V / 3 A, DC 24 V / 1 A | Follow the manufacturer’s data sheet |
| Mechanical life | > 10^5 – 10^6 operations (typical) | Depends on knob material and brand |
| Housing | Plastic / chrome-plated metal | Metal versions feel better |
| Color | Black (standard) / red / green / yellow / blue | Red for emergency, black or green for normal |
| Legend | Manufacturer standard (such as ON/OFF, AUTO/MAN/OFF) or custom | Custom legends quoted separately |
Applications
Selector switches are commonly used in electronics manufacturing for mode selection on machine control panels. Common applications on SMT, EMS and semiconductor machines:
- SMT machine mode selection: 3-position “manual / stop / auto” selector switches on the control panels of solder paste printers, placement machines and reflow ovens; once set, the machine runs in that mode. The arrow type also works well (operators on shift can see the mode from a distance).
- Semiconductor tool mode setting: 3-position “Run / Standby / Maintenance” selection on wafer loader, etcher and CVD tool control panels. Some interlocks are released in maintenance mode, so a maintained selector switch must be used to prevent the machine from running automatically after an accidental touch.
- EMS test fixture mode selection: “test / setup / maintenance” mode selection on ICT and FCT test fixture panels. 3-position maintained, each mode tied to different PLC logic. Custom legends (such as “Test / Setup / Maintenance” in Chinese) help operators identify them.
- Motor forward / reverse selection: 3-position selector switches (forward / stop / reverse) for motor direction on conveyors and mixers; the neutral stop position prevents operators from jumping directly from forward to reverse and causing a shock. 1NO+1NC dual contacts are needed to control the forward and reverse relays separately.
Selection guide: specifications by application
| Application | Positions | Action | Suggested brand |
|---|---|---|---|
| SMT machine main mode selection | 3 (manual / stop / auto) | Maintained | OMRON A22N (Φ22; available on request) |
| Motor forward / reverse | 3 (forward / stop / reverse) | Maintained (some use spring return) | Fuji Electric, Shihlin (available on request) |
| Main switch on large control panels | 3 | Arrow type, maintained | Schneider XB4-BD (Φ22 arrow type; available on request) |
| Momentary test trigger | 2 (test / normal) | Spring return | OMRON A22N spring-return version (available on request) |
| Safety mode setting (key lock) | 2–3 | Key, maintained | Schneider XB5-AG (with key; available on request) |
Three common mistakes when buying selector switches
- Using a push button as a selector switch (once pressed the machine keeps running, with no mode to select).
- Buying spring return instead of maintained (the operator turns it to “auto”, lets go, and it springs back to “stop” — the whole line cannot run).
- Not checking Φ22 / Φ25 (the switch does not fit the panel cutout).
Maintained vs spring return
| Action | Behavior | Typical use |
|---|---|---|
| Maintained | Stays in position until switched manually | Mode selection (manual / auto / maintenance) |
| Spring return | Knob springs back to the center when released | Momentary triggers (test / reset / single action) |
| One-side spring return (semi) | Maintained on one side, spring return on the other | One-way momentary + maintained in the other direction |
Ordering tip: state “maintained” or “spring return” clearly in the specification when ordering — do not just write “3-position selector switch”, which can lead to the wrong item. For the OMRON A22N series, check the return code in the model: M is maintained, L / R / B are spring return. Schneider XB4 selector switches, maintained and spring return, all start with XB4BD and differ in the last digits (for example XB4BD33 is 3-position maintained, XB4BD53 is 3-position spring return); XB4BA is a push button.
Φ22 vs Φ25 cutout: an easy buying mistake
- Φ22 (22 mm): mainstream for Japanese brands (OMRON, Fuji, IDEC).
- Φ25 (25 mm): another cutout size — confirm before buying; the main series of Schneider, ABB and Telemecanique (such as Schneider XB4 / XB5) are in fact also Φ22.
- Φ22 recommended for new lines: parts are readily available in Taiwan and work smoothly with Taiwanese PLC systems.
- Measure the existing hole when retrofitting: measure the cutout before replacing existing parts to avoid buying the wrong size.
Buying in practice: standardize the same specification across a batch of machines (so maintenance parts are interchangeable), and always measure the existing cutout before replacement. Some brands can fit both cutouts with the same switch (for example, the OMRON A22N fits a Φ25 cutout by mounting the fixing nut reversed), but not all brands support this.
Arrow type vs round knob: visual identification
- Round knob (standard): short handle or round knob, fine for close operation and everyday detailed switching. Lower cost and more part choices.
- Arrow type: long, pointed knob whose position is visible from 1–2 meters away. For large control panels, safety modes and low-light environments.
- When to use the arrow type: large machine control panels (operators monitoring from a distance), safety-related mode selection (where misreading could cause an accident), night or low-light environments, multi-person shift work (high consistency required).
- Extra visual aids: the arrow type can be combined with laser-engraved legends, LED backlighting (illuminated type) and color coding (red for emergency, black for normal).
The model on this page is the arrow type; round-knob and other specifications are available on request.
Note: descriptions of brand positioning reflect common industry practice; actual values follow the manufacturer’s data sheets.
Trademarks: OMRON, Fuji Electric, Schneider, IDEC, Shihlin, ABB, Telemecanique and the model names on this page are trademarks or model names of their owners, used here only to identify the products. JIAHON is not the authorized distributor of these brands in Taiwan.
Request a quote
Need a quote or want to confirm specifications? Send us the positions, action (maintained / spring return), cutout size and quantity. Request a quote →