Unique Signalling Unit Indicates more than Open or Closed

Seeing at a glance whether an important valve is open or closed can be crucial. Schubert & Salzer Control Systems has developed the 2040 digital position indicator to provide a totally unique on-site signalling unit. It uses a coloured light signal, visible from a distance, to show the open or closed position of a valve.

Individual coloured signals
The digital position indicator has 4 coloured signals. The open and closed positions are indicated by the yellow and green colours. By a simple press of a button, these coloured signals can now represent the end stops. In addition, when the end stops are reached, the digital position indicator outputs this as a switching signal (NPN) to the contacts on the connector plug (M12x1-5pin).

Besides open and closed positions, the position indicator also signals maintenance information and issues error messages. Errors are indicated by default by a red lamp and a constant signal at the error message output (NPN). The types of errors which are signalled are:
• stuck valves, when the lower and upper end stops are not reached,
• wear in seals, when the lower and upper end stops are exceeded,
• the permissible temperature is too low or has been exceeded,
• the supply voltage is too low.

After installation or exchange, for example, the position indicator uses a white flashing light to indicate that it has not yet been configured with the valve.

Maintenance monitor signals that adjustable values have been reached
The valve position indicator has an integral maintenance monitor. This enables all activities of the position indicator and, therefore, of the valve, to be recorded permanently. The data recorded:
• the hours of operation,
• the valve strokes – therefore the changes in direction and
• the cumulative path travelled by the valve (spindle in the packing).

As a result, maintenance intervals can be set according to the actual operating conditions. After set threshold values are reached, this “maintenance alert” is signalled with pulsating light signals and issued by the error message output. The maintenance alert is self-cancelling, but repeats at set intervals if no maintenance is carried out.

The digital position indicator can be fitted quite as easily as Schubert & Salzer Control Systems GmbH’s digital positioners to linear and part-turn actuators for pneumatic valves. They are fitted directly on to the valve using a standardised adapter. A sensing pin detects the stroke or angular position of the actuator and converts it into an analogue signal. The sensing pin and stop are matched to the nominal size and actuator size of the valve. The electronics evaluate the analogue signal of the path reading and generate the correspondingly coloured light signal or appropriate error messages, as the case may be. In addition, switching contacts (NPN) are available for further processing in superimposed systems. Adaptation is semi-automatic needing just the touch of a button and this is completed after a few runs up to the on and off positions.

The setting of all parameters from the colour selection (RGB colour scale) to the maintenance values is done by means of a USB adapter with the DeviceConfig adjustment software (from version 7.02.00). The current software version can be downloaded free of charge. Optionally, the digital position indicator is delivered with a Bluetooth communications module so that the parameterising can be done wirelessly in places where access is difficult.

Schubert & Salzer Control Systems
Tel: +44 (0) 1952 46 20 21
www.schubert-salzer-uk.com

Published: 28th June 2013