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Limit switch box for pneumatic actuators with NAMUR mount and open-closed position indicator
LSB-01 · Pneumatic actuator accessories

Limit Switch Box for Pneumatic Actuators, NAMUR Direct Mount

Mounts on top of any NAMUR-compatible actuator and tells your control system whether the valve is open or closed. Mechanical limit switches trip at each end position; the signal goes back to the PLC for monitoring, alarms and interlocks.

Body materialIP67 enclosure
Contact ratingAC 250 V 16 A, 125 V 16 A · DC 250 V 0.3 A, 125 V 0.6 A, 30 V 10 A
Product overview

Product overview

A limit switch box for pneumatic actuators sits on top of the actuator and answers one question for the control system: is the valve actually open or closed? Automation assumes a valve moved when it was told to. The switch box checks. Mechanical limit switches inside trip as the valve reaches each end position and send an electrical signal back to the PLC or DCS, so the plant knows the position of every automated valve without anyone standing next to it.

It mounts through the NAMUR interface, the same standard bolt pattern and shaft connection that our solenoid valves use, so it fits any NAMUR-compatible quarter-turn actuator, including actuators you did not buy from us. Tell us which actuator you are using when you order and we will confirm the fit. When it ships with one of our pneumatic ball valves, the valve, the actuator, the solenoid valve and the switch box are assembled and tested together before they leave.

What the signal buys you is more than a light on a panel. If a valve fails to reach its position, the switch does not send its signal, and the control system can raise an alarm or hold an interlock before a mis-positioned valve causes a problem: a pump that must not start until its isolation valve is open, a line that must be confirmed closed before maintenance begins. That is why a switch box is treated as a safety component in process plants, not a convenience.

NAMUR direct mount — fits any NAMUR-compatible quarter-turn actuatorMechanical limit switches trip at open and closed end positionsOpen or closed signal to your PLC or DCS for monitoring and interlocksShares the interface with our solenoid valve; ships assembled and tested with the valve
Technical specifications
Model
LSB-01
Signal output
2 SPDT mechanical switches, open and closed
Body
IP67 enclosure
Contact rating
AC 250 V 16 A, 125 V 16 A · DC 250 V 0.3 A, 125 V 0.6 A, 30 V 10 A
Operation
Mechanical limit switches · open and closed position feedback · NAMUR direct mount
Applications

Applications

Remote valve position feedback — Confirms open or closed to the PLC or DCS so operators see every automated valve from the control room.Automated valve packages — Mounted with the solenoid valve on the same NAMUR interface as one assembled, tested package.Safety interlocks — Holds a pump or a downstream step until the valve is confirmed in position; a missing signal raises the alarm.Water and wastewater treatment — Position monitoring on isolation and diverting valves across treatment trains.Chemical and process plants — Valve status across process lines where the operator cannot walk to every valve.
Quality assurance

Every valve leak tested.

Each unit is checked for leakage before shipment.

Custom options
Supplied alone for an actuator you already have, or assembled with our actuator and valve→Ordered together with our solenoid valve on the same actuator→Laser marking and packaging to your artwork→
FAQ
What does a limit switch box do?

It reports the valve's position. Mechanical switches inside trip when the valve reaches its open or closed end position and send an electrical signal to your control system, so you know the valve's status without standing next to it.

Which actuators does it fit?

Any NAMUR-compatible quarter-turn actuator, ours or another maker's. Tell us the actuator you are using so we can confirm the fit.

What type of switches does it use?

Two SPDT mechanical limit switches. They trip on contact as the valve reaches each end position, and each switch gives you a normally-open and a normally-closed contact.

Why does position feedback matter?

Automation assumes a valve moved when commanded. The switch box verifies it actually did. If the signal is missing, the control system can raise an alarm or hold an interlock before a mis-positioned valve causes a problem.

Can I order it with the solenoid valve?

Yes. Both mount on the same NAMUR interface. Order them together with one of our pneumatic ball valves and the whole package ships assembled and tested.

Other builds See the full range →
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Send a part number, a spec sheet or a photo. We will price it.