A positioner controls the actuator to achieve a requested valve position. A solenoid valve switches an air path according to an electrical command. Their roles differ, and some packages use both.
For modulating control
A positioner compares the command with measured position and adjusts actuator air as required. The offered model must suit the signal, actuator type and application. Feedback linkage quality and tuning influence performance; installing a digital positioner cannot compensate for a loose shaft connection or an unsuitable valve size.
For on/off control
A solenoid often directs air to open or close the actuator, with limit switches reporting endpoint status. Select its pneumatic function, voltage, flow capacity and failure state as part of the circuit. A small solenoid or restrictive tubing can make a large actuator move slowly even when static air pressure is adequate.
For combined functions
A shutdown arrangement may include a positioner for normal control and a solenoid for a defined override action. The exact piping and electrical logic must be reviewed so the devices do not work against each other. Specify the required behavior before selecting accessory brands or ordering codes.
Practical checklist
- Modulating or discrete command requirements.
- Electrical signal and supply details.
- Air-path capacity and actuator volume.
- Endpoint feedback and defined failure response.
Discuss your application
Send the process conditions and required valve function for a configuration review. Request a technical quotation ↗