SMC ZSM1-T121 Vacuum Switch

SMC ZSM1-T121 Vacuum Switch is a diaphragm‑style, SPST‑NO switch that delivers a switched supply‑level voltage when the sensed vacuum crosses its set point. It covers a vacuum range of -80 to -27 kPa with a regulating range of -27 to -80 kPa and a hysteresis up to about 20 kPa, offering repeatability of ±10% or less. The device can be powered by 4.5 to 28 VDC for the solid‑state version or 100 VAC/DC for the reed version, and it ships with a standard 0.5 m lead wire (with longer options such as 3 m available). Port options include 1/8 NPTF or 1/8 RC, and the unit can be mounted on ZM or similar adapters; overall, the compact body measures roughly 52.5 mm in length, 15 mm in width, and 23 mm in height, weighing about 65 g. Rated for a maximum operating pressure of 0.5 MPa and an ambient/ fluid temperature range of -5 to +60°C (no freezing), the ZSM1‑T121 is the diaphragm variant of the ZSM1 family designed for reliable vacuum monitoring in pneumatic automation, signaling control logic or alarms when a negative‑pressure condition is reached. This model is commonly cataloged as ZSM1‑T121 (ZSM1‑121) and is supported by SMC and authorized distributors worldwide.