Fieldbus & Industrial Networking


Second-generation valve positioner uses HART or Profibus

April 2000 Fieldbus & Industrial Networking

The Arcapro positioner is a valve positioner of the second-generation which is characterised by substantially increased functions, higher reliability and a more compact layout. It has been designed as a compact instrument with a modern and practical design, providing for a reliable operation even under very rough ambient conditions. The display is also visible during operation so that the operating data can be checked with a quick glance at the instrument.

The positioner allows the following modes of operation:

* Automatic operation.

* Manual operation.

* Initialisation.

* Parameterisation.

When the instrument cover is taken off the parameterisation of the positioner can be carried out by means of push-keys. The following values are adjustable:

* Direction of setpoint.

* Characteristic curve.

* Split-range operation.

* Limitation of output signal.

* Tight shut-off function.

* Function of the error report signal.

* RAM function.

Alternatively, the parameterisation can also be carried out via the HART interface or the Profibus-connection. By using the corresponding operating software all relevant values of the control valve may be indicated, eg number of valves, type of actuator, mode of operation, process and diagnostic data:

* Zero point and range.

* Setting speed.

* Setting increments.

* Dead band.

* Number of error reports.

* Number of directional changes.

* Stroke integral value.

On the user shell the current diagnostic data can be compared on-line with former maintenance data. Deviations can be seen and actuator problems may be discovered at an early stage so that repairs can be planned ahead. The preventive maintenance may thus be planned more efficiently and production stops will be reduced to a minimum.

The energy supply to the Arcapro positioner is achieved with the analog twin-core system by the input current IW. In case of three and four-core systems the auxiliary voltage EH is used. With a bus-connection, the instrument is supplied with a constant current by the bus.

The position of the actuator is transmitted to the potentiometer by a shaft and a gear with sliding clutch. The gear allows the adaption to small or large positioning angles so that strokes of 3 mm can be measured with the same accuracy as setting angles of 100°. The slide-clutch is used for the adjustment of the potentiometer when commissioning the instrument.

The major part of the positioner is the electronic board with the microprocessor and the indicating and operating elements. Here the analog, or - in the case of a bus connection – the digital setpoint signal XS is compared with the current value signal of the potentiometer. Based on a special control algorithm the controller derives signals that actuate the two piezo elements, generating the pneumatic positioning signal. Restrictor-valves allow the adaption to the volume of the actuator.

The LCD display indicates the operating conditions and the adjusted parameters or - in the case of automatic operation - the current stroke or angular value with four digits. The display is constantly visible through the screen window in the automatic operating mode.

The modular design allows optional components to be installed by lifting the cover and plugging them in.

The optional analog or binary modules are used for the transmission of the 4 to 20 mA actuator position signal or the output of two-position switches to the control system. Alternatively, the position signal can also be sent via HART or Profibus. The fault-signal output informs of power failure or deviation from a setpoint value.



Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

IO-Link portfolio for decentralised automation
Turck Banner Fieldbus & Industrial Networking
Turck Banner has expanded its IO-Link portfolio with a robust IO-Link master, a compact IO-Link master in IP20 and an I/O-hub with an additional power supply.

Read more...
Valve & Automation’s new Secunda Valve Repair Centre
Valve & Automation News
On 1 November 2021, Valve & Automation’s Secunda Valve Repair Centre opened at 18 Kingfisher Street, Ext 57, Secunda, Mpumalanga.

Read more...
The ultimate control valve
Valve & Automation Valves, Actuators & Pump Control Editor's Choice
Zwick has designed its TRI-SHARK range of Triple Eccentric Valves to be used in control or throttling applications as well as for pure on/off functionality.

Read more...
Turck Banner’s Profinet integration with S2 redundancy
Turck Banner Fieldbus & Industrial Networking
The TBEN-L5-8IOL is an IO-Link master module in IP67 that supports S2 system redundancy. The master establishes a logical communication relation to more than one controller and combines high availability with a wide range of potential uses through IO-Link in the field.

Read more...
Chinese LNG tanker fitted with ARCA anti-surge valves
Valve & Automation Valves, Actuators & Pump Control
ARCA anti-surge valves avoid surging by accurately adjusting the gas circulation or blow-off flow, effectively protecting the safety of the compressor unit.

Read more...
Siemens gateway for the process industry
Siemens South Africa Fieldbus & Industrial Networking
Siemens has introduced the Sitrans CloudConnect 240: a new gateway for the process industry. It provides a second data channel, that is used to transmit data from any HART-based field devices to the IT world.

Read more...
Eliminate bearing failures in TOVs
Valve & Automation Valves, Actuators & Pump Control
Bearing failures are among the highest root causes of failure in triple offset valves (TOV) for tight shutoff applications. This issue is directly attributed to the need to have metal bearings with very ...

Read more...
Cleaning machine 4.0
ifm - South Africa Fieldbus & Industrial Networking
For the digitalisation of its industrial cleaning machines, the French company Mecanolav counts on IO-Link sensors from ifm electronic.

Read more...
RS Components supplies Siemens intelligent IIoT gateways
RS Components SA Fieldbus & Industrial Networking
Maximising operational efficiency, these UL-approved units have been designed to deal with the capture and pre-processing of data, before subsequently forwarding it on.

Read more...
Secure gateways for power communications
Fieldbus & Industrial Networking
Moxa has introduced a new series of secure hardened Modbus-to-BACnet protocol gateways.

Read more...