SMC Stopper Cylinder Selection Guide
Start with the weight of the pallet and the transfer speed, then confirm bore, stroke, and rod end. RSQ-Z and RS2H are rated for a maximum operating pressure of 1.0 MPa.
| Series | Mounting Height | Bore (mm) | Standard Stroke (mm) | Rod End | Body Mounting |
|---|
| RSQ-Z / RSDQ-Z | Fixed | 16, 20, 32, 40, 50 | 16: 10, 15
20 and 32: 10, 15, 20
40 and 50: 20, 25, 30 | Round bar, chamfered, roller, female rod end versions, lever (32 to 50mm) | Through-hole or both ends tapped |
| RSQ / RSDQ (12mm) | Fixed | 12 | 10 | Round bar, chamfered, roller | Through-hole and tapped in one tube |
| RSG / RSDG | Adjustable | 40, 50 | 20, 25, 30 | Round bar, chamfered, roller, lever | Flange, height adjustable |
| RS2H | Fixed | 50, 63, 80 | 50 and 63: 30
80: 40 | Lever with built-in adjustable shock absorber, resin or carbon steel roller | Flange |
| RSH | Fixed | 20, 32 | 20: 15
32: 20 | Lever with built-in adjustable shock absorber, resin or carbon steel roller | Flange |
Sizing by Pallet Weight and Speed
SMC sizes stoppers from operating range charts of transferred weight versus transfer speed. Two worked examples from the SMC catalogs show the scale of each series:
- A 30 kg pallet at 15 m/min with a roller rod end falls in the RSQ 40mm operating range. With a lever rod end, the same 40mm RSQ handles 60 kg at 15 m/min.
- A 300 kg pallet at 20 m/min (friction coefficient 0.1) calls for the RS2H 63mm bore. RS2H charts run up to 1,000 kg.
- Higher lateral load from conveyor friction requires higher operating pressure, so check the lateral load chart as well as the energy chart.
Rod End and Lever Options
| Rod End (RSQ-Z code) | Use It When |
|---|
| Round bar (none), Chamfered (K), Female rod end versions (F, G) | Light loads and simple stops. Chamfered rods are non-rotating. Female rod ends accept a custom stop block (not on 12mm). |
| Roller (R) | Roller contact against the pallet. In SMC's sizing example, a 40mm roller stopper handles a 30 kg pallet at 15 m/min. |
| Lever, fixed absorber (L) or adjustable absorber (B) | Heavier or faster pallets. The built-in shock absorber softens the stop; the adjustable type is tuned with an adjustment bolt. 32, 40, and 50mm only. |
| Lever with lock mechanism (D) | Light pallets that would rebound off the shock absorber spring. The lock holds the lever upright. |
| Lever with cancel cap (C), or lock and cancel cap (E) | The cancel cap holds the lever horizontal so selected pallets can pass without stopping. |
RS2H offers the same lock mechanism (D), cancel cap (C), and lever detection switch (S) as options on every bore. The lever detection switch signals that a pallet has reached the stop position.
Ordering Notes That Prevent Mistakes
- Magnet for auto switches: the D in RSDQ and RSDG means built-in magnet. Without it (RSQ, RSG), auto switches cannot be mounted.
- Action code: D is double acting, B is double acting with spring loaded, T is single acting with spring extend (the spring raises the stopper, air lowers it).
- Port thread: no symbol is M thread (12 and 16mm) or Rc (20mm and up), TN is NPT, TF is G, and F is built-in One-touch fittings (RSQ-Z 20 to 50mm).
- Auto switches ship with the cylinder but are not assembled. RSQ-Z accepts compact switches on four faces without separate brackets; RS2H accepts D-M9 and D-P3DWA switches on three sides.
- Lever direction: the RS2H roller lever can be repositioned in 90 degree steps to suit the transfer direction.
- Special versions: 25A- RSQ-Z models are SMC's secondary battery compatible version. Long stroke (-XB11) and special port location (-XC3) are made to order.
Discontinued SMC Stopper Series and Replacements
Each old part number page on our site lists its direct replacement. SMC lists these replacements as mounting interchangeable.
| Discontinued Series | SMC Discontinued | Replacement | How the Part Number Changes |
|---|
| RSQ / RSDQ, 16 to 50mm | Apr 2018 | RSQ-Z / RSDQ-Z | Add Z after the stroke and rod end letters. RSDQA50-30D becomes RSDQA50-30DZ. 12mm RSQ is still current. |
| RSH 50, 63, 80mm | Aug 2005 | RS2H | RSH80-40TM becomes RS2H80-40TM. RSH 20 and 32mm are still current. |
| RS1H | Aug 2012 | RS2H | Same mounting pitch and roller height. RS2H is up to 22% lighter with a shorter tube. |
| RSA, RSA-X721 | Sep 2015 | RS2H-X2700, RS2H-X2701 | Made to order. Cylinder tube is shorter. Contact us to confirm the full code. |
Stopper Cylinder FAQ
What is the difference between SMC RSQ and RSQ-Z?
RSQ-Z replaced the RSQ in 16 to 50mm bore when SMC discontinued RSQ in April 2018. RSQ-Z is mounting interchangeable, adds female rod end options for ten rod end styles in total, and accepts compact auto switches on four faces without mounting brackets. The 12mm RSQ remains in production.
Which SMC stopper cylinder should I use for heavy pallets?
Use the RS2H heavy duty stopper in 50, 63, or 80mm bore. It has a lever with a built-in adjustable shock absorber that stops pallets gently, and SMC's operating range charts for the RS2H extend to 1,000 kg. Size it from the pallet weight, transfer speed, and conveyor friction coefficient.
What does the D mean in RSDQ or RSDG?
The D means the cylinder has a built-in magnet for auto switches. RSQ and RSG without the D have no magnet and cannot detect position with an auto switch. Order the D version whenever the PLC needs a stopper up or down signal.
When do I need a stopper with a lock mechanism?
Choose a lock mechanism when pallets are light enough to bounce back off the lever shock absorber. The lock holds the lever upright after impact so the pallet stays at the stop position. It is available on RSQ-Z lever models (D and E rod ends) and as option D on the RS2H.
What is the difference between fixed and adjustable mounting height stoppers?
Fixed mounting height stoppers (RSQ-Z) mount directly to the conveyor frame at one height. Adjustable mounting height stoppers (RSG) can be raised or lowered to match the distance to the workpiece, which helps when conveyor heights vary or are not yet final.
What air pressure do SMC stopper cylinders need?
RSQ-Z and RS2H stopper cylinders have a maximum operating pressure of 1.0 MPa and a proof pressure of 1.5 MPa. Set the working pressure from SMC's lateral load chart, because friction between the conveyor and the pallet pushes sideways on the stopper and higher lateral load needs higher pressure.
Need help sizing a stopper or finding a replacement?
Send us the pallet weight, conveyor speed, and your current part number. Automation Distribution, an authorized SMC distributor, will confirm the series, rod end, and auto switch.
Contact Automation Distribution
