
The AirTAC Airtac CMSG Reed Switch Sensor CMSG-020-H is a genuine CMS magnetic position switch. It senses the magnet ring in a pneumatic cylinder's piston and signals when the piston reaches that point, giving a 2-wire output on 5-240 V AC/DC with a 2 m flying lead. It only works on a cylinder that carries a piston magnet.
The CMSG-020-H is a reed-type magnetic position switch in the AirTAC CMS family. Inside is a mechanical reed contact that closes when the piston magnet of an AirTAC cylinder - fitted with the magnet option - passes the mounting point. It is a 2-wire switch that wires in series with your load like a plain contact, runs on 5-240 V AC or DC with no polarity to observe, carries a 2 m flying lead, and is rated IP64. The H suffix marks the high-temperature version, intended for positions near heat that a general-type switch should not sit in.
Because the contact is mechanical rather than solid-state, there is no leakage current to bleed into a PLC input, though a reed contact has a finite switching life and is best suited to lower duty cycles - confirm ratings from the datasheet. The G in the code is a fit code: it selects the body shape that seats into a matching cylinder sensor groove. Check it against your cylinder's groove before ordering, and remember the switch alone senses nothing - the cylinder must have a built-in piston magnet.
| Model | Airtac CMSG Reed Switch Sensor CMSG-020-H |
|---|---|
| Family | CMS — Reed switch cylinder sensor |
| Technology | Reed (magnetic contact) |
| Output | 2-wire |
| Outputs in this family | 2-wire contact |
| Lead / connector | 2 m flying lead |
| Supply voltage | 5-240 V AC/DC |
|---|---|
| Protection rating | IP64 |
| Version | High-temperature version |
| Profile letter | G (cylinder-groove fit) |
| Profiles in this family | E, G, H, J |
| Detects | Piston magnet ring inside the cylinder |
A reed contact switches a wide window, 5-240 V AC or DC, which is why it suits AC circuits and relay logic. IP64. The CMS range has no RW / IP68 option - that belongs to DMS and EMS. Switching distance, response time, current rating, voltage drop, LED behaviour, contact life, weight and dimensions are not published in our data set — ask us and we will confirm from the factory datasheet.
| CMS | Reed switch cylinder sensor — reed (magnetic contact). |
|---|---|
| G | Profile letter: the mounting / groove type that fits a particular cylinder body. This family offers E, G, H, J. It is a fit code, not a performance grade. |
| 020 | 2 m flying lead. 020 / 030 / 050 / 100 are 2 / 3 / 5 / 10 m flying leads; M08 and M12 are M8 / M12 connector versions. |
| H | High-temperature version. On a CMS the suffix -H is the high-temperature version — do not confuse it with the H profile letter. |
We do not hold the full profile-to-cylinder-series table, so confirm the profile letter against your cylinder model before ordering — send us the cylinder part number and we will check the fit.
The split is electrical, not quality. Solid-state DMS and EMS are DC-only and suit modern PLC inputs; the reed-based CMS switches a much wider window, so it is the one for AC circuits, relay logic and older panels. The RW (IP68) option exists on DMS and EMS only.
| This switch | CMSG · 2-wire · 5-240 V AC/DC |
|---|---|
| Consider DMS | the solid-state range with NPN / PNP 3-wire outputs (DC only) |
| Consider EMS | the mini 2-wire solid-state switch (DC only) |
| Mounting parts | F-MQ (round body), F-ACT (tie-rod) |
Signals end-of-stroke on the gate cylinder of an industrial baking oven, where ambient heat around the carriage demands the high-temperature H construction.
Confirms the clamp cylinder on a hot-stamping cell has reached the workpiece, feeding a 2-wire contact straight into the machine relay chain at line voltage.
Monitors retraction of the tilt cylinder beside a foundry ladle, where radiant heat rules out a general-type sensor and AC control circuits are already in place.
Choose CMS when the circuit runs on AC, runs on a very wide DC window, or simply calls for a passive contact that behaves like a mechanical limit switch. The 2-wire output drops into series wiring with almost no setup. This variant adds the H high-temperature construction - pick it over the general CMSG-030 or CMSG-050 when the switch will sit in a hot zone. If you are on a low-voltage DC PLC and want faster, bounce-free cycling, compare against the electronic DMS or EMS families instead. Flying lead keeps the install simple and cut-to-length; the profile letter must match the cylinder groove for the switch to seat correctly.
Quick checklist
Use the F-MQ bracket on round-body cylinders and F-ACT on tie-rod cylinders where there is no groove to seat the switch. Both are ordered separately from the switch. Switching distance and mounting dimensions come from the factory datasheet — ask us for the sheet that matches your cylinder.
It is a reed (magnetic reed) position switch with a 2-wire contact output, supplied from 5-240 V AC or DC with no polarity, protected to IP64, and fitted with a 2 m flying lead. The H code denotes the high-temperature version of the general CMS type.
Only if the circuit suits a reed contact. The CMS is mechanical: it works on AC or DC across a very wide voltage span and leaks nothing in series wiring, but its contact has a finite life and can bounce. A DMS or EMS electronic switch is solid-state and DC only, better for fast PLC counting. Also confirm the G profile matches your cylinder groove and that the cylinder carries the piston magnet option.
Genuine AirTAC parts produced by AirTAC factory.
Covers non-human-caused product damage.
Standard models are processed and dispatched in 3-5 business days.
Most inquiries answered within 7-8 hours.
Send us the quantity, your cylinder model (so we can confirm the profile fit) and the destination. We confirm price, availability and lead time — usually within 7-8 hours.