Process control: Valve positioner for safety systems
SVI II ESD valve positioner from Masoneilan-Dresser, introduced last week in Control Engineering magazine, is SIL3-compliant and said to be a one wire solution for emergency isolation valves.
Oak Brook, IL and Avon, MA —SVI II ESD from Masoneilan-Dresser , an extension of the company's SVI II AP valve positioner, marks the company's entrance into the safety system arena. SIL3-compliant device is designed in accordance with IEC61508 and is suitable for use in safety instrumented functions. The product, introduced last week in the February issue of Control Engineering magazine , is used as an emergency isolation valve controller equipped with state-of-the-art diagnostics to improve the overall safety integrity of the safety instrumented loop.
The company calls the product a breakthrough because it allows for a one-wire solution for both the safety shutdown function of an isolation valve and partial stroke testing (PST) capability. Masoneilan adds that making maximum use of artificial intelligence at the device level through analysis of incoming data from multiple sensors gives the user usable, actionable information regardless of PST execution method.
SVI II ESD can be implemented using a 4-20 mA signal, 0-24-V dc, or both. One 4-20 mA solution is said to be best because it is SIL3 capable at 4 mA and allows the device to execute the safety function while active. Benefits are realized in capturing data during shutdown events, allowing continuous HART communications during a trip and facilitating local panel annunciation using the built-in discrete outputs.
The SVI II ESD allows flexible PST execution and automatically captures the PST in its non-volatile memory and stores the analysis. Annunciation of the results is realized using HART, the local LCD, or discrete signals. Two signatures can be stored; ValVue ESD Lookout software (standalone or integrated) automatically and regularly synchronizes the database with field data. The PST, says the company, is implemented so that it does not interfere with the safety function; the product's architecture is designed to segregate the two functions.
—Control Engineering Daily News Desk
Edited by Jeanine Katzel , senior editor