Which brand of locators allow for online replacement of the locator?

Brands that allow for the online replacement of locators include Siemens, Honeywell, and others. The specific replacement steps are as follows: 1. First, ensure that the system is in a stable state to guarantee safe operation. 2. Close the relevant valves for which the positioner needs to be replaced, and disconnect the power and signal connections. 3. Remove the old locator, being careful to keep the interfaces and sealing parts clean. 4. Install the new locator, align it with the interface, and secure it with screws. 5. Reconnect the power and signal cables, and ensure that they are connected correctly. 6. Open the valve and power on to test whether the new locator is working properly. 7. Observe the operation for a period of time to confirm there are no abnormalities. Please adjust the operation steps according to the actual situation and specific model. .

Online replacement refers to the replacement of the positioner of a control valve without a bypass. A prerequisite for online replacement is the presence of a handwheel, which ensures that manual adjustment can be carried out during the replacement process to meet the requirements of industrial production； There is another condition: after the locator is replaced, there is no need to perform a full-stroke switch test. Are there such locators?

If the control valve does not have a handwheel, mechanical stops can be installed on-site to fix the valve in its current position; the locator can be replaced online, but it cannot be adjusted. It has been applied only to the SAMSON locator so far, but the deviation is around 2%.

There probably isn’t such a locator; the position where the locator is installed each time isn’t exactly the same. After installation, online calibration is usually required, otherwise it will affect the accuracy of adjustment as well as other parameters like stroke. If the requirements are low, many options with hand wheels can meet them.

First, it is necessary to ensure that the valve opening does not change when replacing the positioner (the handwheel is used to fix the valve position). Second, for the new positioner, select a spare valve with a similar stroke range and test it properly