Patent ID: 8576086
Filing Date: 2013-11-05
Classification: F15B

Abstract:
1. A limit signal indicator for determining first and second positions of a pneumatically operated positioning device actuated by a positioning drive, comprising: a position sensor for detecting a position of the positioning device; a first signal transmission contact, a second signal transmission contact, and a microprocessor connected to the first and second contacts by respective communication lines; the first signal transmission contact outputting a first electrical limit position signal indicating that the positioning device is in the first or the second position and the second signal transmission contact outputting a second electrical limit position signal different than said first electrical limit position signal indicating that the positioning device is in the first or the second position, or the first and the second electrical limit position signals indicating a position of the positioning device different than the first and the second position, and wherein when one of said first and second limit position signals is above a respective first predetermined set limit value and the other of said first and second limit position signals is below a respective second predetermined set limit value the positioning device is identified as being in said respective first or second position; the first signal transmission contact being connected to a respective first switch amplifier and the second signal transmission contact being connected to a respective second switch amplifier; the first switch amplifier generating and transmitting to an external processing location a first emergency signal in case of a signal transmission malfunctioning within the limit signal indicator of a signal transmission of at least one of said first and second electrical limit position signals, said first emergency signal having a value above a maximum limit value or below a minimum limit value; and upon detecting by said microprocessor a specific operational malfunctioning of the limit signal indicator, the positioning device, or the positioning drive, or a combination thereof, said specific operational malfunctioning being other than said signal transmission malfunctioning, said microprocessor executing an emergency procedure according to which a second emergency signal is generated and transmitted by said second switch amplifier to said external processing location, a value of said second emergency signal substantially corresponding to the value of the first emergency signal.