1. Can we use a control valve without positioner?
Control valve can not be without positioner. The purpose of the positioner is to control the control valve stroke so as to keep the valve in desired position. The positioner receives signal from the controller, and send the boosted signal to the actuator to reach the desired position as and when the valve reaches the desired position the positioner cuts the boosted signal to the actuator and keeps the position.
2. Why 4-20 mA signal is preferred over a 0-10V signal?
Generally in a transistor some amount of voltage is required for turning it on. This voltage is the cut in voltage. Up to this voltage the exists a nonlinearity in its characteristics. Beyond this cut in voltage the char. of transistor is linear. This nonlinear region lays between 0- 4ma, beyond 4ma it linear. This is why 4-20 ma range is used.
3. What is remote mount with MTA option? (In case of Dual Sensor Vortex Flowmeter, rosemount has written in its Catalog drawings)?
Remote mount with MTA means MTA connector for mounting remote connection. MTA is the Connector used for connection. Generally we called it MTA Connector. There are many types of MTA connector such as MTA 100connectors, Mta 156 connectors etc.
4. How to write the program for single push button by using Ladder diagram?
1. Create a Push button
2. Connect a Counter series to PB
3. Create a compare button
4. Initialize 1 at one end
5. Counter output in another
6. Connect the Coil which has to be energized
7. Initialize 2 at one end
8. Counter output in another
9. Connect the Coil which has to be reenergized.