AirTAC Pneumatics
AirTAC CMS Series Reed Switch Cylinder Sensors
The AirTAC CMS is a reed-switch cylinder position sensor with a 2-wire contact that switches 5-240 V AC or DC - the pick for AC circuits, relay logic and older panels where DC-only electronic switches cannot go.
inventory_240 models availableSeries Overview
The CMS is AirTAC's reed-type cylinder position sensor. It clips into the groove of a magnet-equipped cylinder body and detects the piston magnet: when the piston reaches the switch, the contact closes and your circuit sees the position. The sensing element is a genuine mechanical reed contact sealed in glass, not a solid-state circuit. That construction is what gives the CMS its standout feature - a switching window of 5 to 240 V AC or DC on a 2-wire connection, wide enough to drive a relay coil or an indicator straight from an AC panel. Protection class is IP64.
Across the range, the profile letters E, G, H and J select the mounting groove that fits a particular AirTAC cylinder body. They are fit codes, not performance grades: a CMSJ is not better than a CMSG, it simply suits a different groove. Every CMS is 2-wire - there is no NPN or PNP version. Lead options are flying leads of 2, 3, 5 or 10 m, or an M8 or M12 connector version for machines wired with pre-made cables. The -H suffix marks the high-temperature type for hot ambient positions. Store codes read CMSJ-020, CMSE-030, CMSG-050, CMSH-020, and the B52- prefix identifies the copper-free line.
Two details worth knowing before you order. First, the letter H means different things by position: as the profile (CMSH) it is a groove fit, while as a suffix (-H) it is the high-temperature version - read the code, not just the letter. Second, a CMS is useless on a cylinder without a piston magnet, so confirm your cylinder carries one.
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Typical Applications
Relay-logic panels on older machinery
On legacy production lines controlled by relays at mains voltage, the CMS reed contact switches 5-240 V AC directly - driving a relay coil or stack light without an interposing DC supply that solid-state DMS or EMS switches would need.
Packaging line end-of-stroke signalling
Pusher and gate cylinders on packaging machines report fully-advanced position to the controller. The M8 and M12 connector versions of the CMS drop straight into pre-made sensor cable looms, keeping changeover wiring simple.
Clamp confirmation on fixture cylinders
A magnet-equipped SC or SDA clamp cylinder fitted with a CMS closes a contact at full clamp, proving the part is held before the next station cycles. The 2 m or 3 m flying leads suit short runs to the panel.
Hot positions on drying and curing machines
Where the switch sits near an oven, dryer or curing zone, the -H high-temperature CMS type is specified for the job; its temperature limit is stated in the datasheet, so confirm it against your ambient before ordering.
How to Choose the Right Model
Match the profile letter to your cylinder body first - that is what decides whether the switch physically fits, and it is the step buyers most often skip. Send us your cylinder model and we confirm the correct letter. Then check the circuit: choose CMS when the voltage is AC, when it sits above the DC window the electronic switches accept, or when you are feeding a relay or an older panel directly. Pick the lead length (2, 3, 5 or 10 m) for hard-wired panels, or the M8 / M12 connector version where the machine uses pre-made sensor cables. Where ambient heat is the constraint, order the -H high-temperature type. Before ordering, confirm five points: the cylinder series and groove, the circuit voltage and AC or DC, that a 2-wire contact suits your input, the lead or connector, and standard or -H.
Step out of the series when the input demands it: the AirTAC DMS electronic range adds NPN and PNP 3-wire outputs for modern PLC inputs (with an RW/IP68 option), and the mini EMS covers compact 2-wire DC positions. The F-MQ round-body and F-ACT tie-rod mounting brackets are separate accessories, not switches. Every CMS requires a cylinder with a piston magnet, such as magnet-equipped SC, SI, SU, SDA or MAL cylinders.
Quick checklist
- ✓ Required force at your working pressure
- ✓ Stroke and available mounting space
- ✓ Port / thread type (PT / NPT / G)
- ✓ Sensor / magnet option (-S)?
- ✓ Side load — consider a guided model
Frequently Asked Questions
The CMS is a 2-wire reed contact that switches 5 to 240 V AC or DC, with IP64 protection. Because the element is a mechanical reed sealed in glass rather than a solid-state circuit, one part covers everything from a low-voltage DC signal circuit to a 230 V AC relay coil - a window the DC-only DMS and EMS electronic switches do not offer. Switching current ratings are given in the datasheet for the specific model.
The letter selects the mounting groove that fits a particular AirTAC cylinder body. It is a fit code, not a performance grade: a CMSJ is not better than a CMSG, it suits a different groove. The full profile-to-cylinder mapping is not published on this page, so send us your cylinder series and model and we confirm the correct letter before you order.
Only on a cylinder that carries a piston magnet - such as magnet-equipped SC, SI, SU, SDA or MAL cylinders. Without a magnet ring the switch has nothing to detect. You will also need the profile letter that matches your cylinder's groove. Genuine AirTAC switches ship under their original codes such as CMSJ-020, CMSE-030, CMSG-050 and CMSH-020, with the B52- prefix marking the copper-free line.
In the ordering code CMS{profile}-{wiring}, the wiring digits 020, 030, 050 and 100 give 2, 3, 5 or 10 m flying leads, while the M08 and M12 connector versions take pre-made cables with pigtail lengths of 0.5, 1, 2 or 3 m. The -H suffix adds the high-temperature type. If your controller needs an NPN or PNP 3-wire signal for a PLC input, step to the AirTAC DMS electronic range - every CMS is a 2-wire contact only.
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