Applications

Dual Process Input

A second process input can be used to determine the highest or lowest value of two inputs, select between these inputs or calculate a derived value. Typical example could be indication of average signal in a tank containing solids or measurement of the second melt pressure input on an plastic extruder.

Setpoint Tracking Policeman

Sometimes in applications with a setpoint that is frequently being adjusted possibly due to differing products or that the main PID controller is running a ramping setpoint it is also necessary to change the alarm setpoint. Using Modbus Master communications it is possible to send the controller setpoint to a slave alarm unit and for the slave to add a deviation setpoint referenced to the transmitted value.

Multi-Way Input Selector

When combined with the model 767S selector switch up to twelve thermocouples or 2-wire signals, and six Pt100 signals can be viewed using one indicator. Selection is made via a front panel rotary switch which includes clear indication of the channel selected.

Custom Linearisation

Provides a method of linearising an input measurement using a curve defined by up to 15 points. The linearisation points may be continuously increasing or continuously decreasing. This is particularly useful in level applications where the volume of liquid is not linear to the height dimensions of the vessel.

Strain-Gauge / Loadcell Input

The strain gauge feature in the 32h8i and 2408i makes them ideal for melt pressure and other load cell inputs such as weighing applications. The 32h8i can accept one strain gauge input with transducer excitation and user calibration facilities. Additionally the 2408i can accept an additional strain gauge input therefore allowing differential alarms between inputs such as those required in melt pressure applications to indicate screen blockage.

Isolated Retransmission

In many DCS installations local indication at plant level is required. Often the measurement sensor is connected to the local indicator and its linearised 4-20mA signal retransmitted to the DCS system. It is important that to minimise ground loops and earthing problems that the retransmitted signal is isolated from the sensor input.

Colour Change in Alarm

When viewing indicators from distance it is often only required to know if any abnormal plant conditions are occurring. A convenient way of detecting such conditions is to make the display change colour from green to red when an alarm occurs. This feature alerts the attention of the operator who can then investigate the problem.

Alarm Messages

The User Interface on 3200: indicators are customisable to show plant information in the format that is most useful for the user. Customisable scrolling text can indicate event and alarm conditions, to trigger another function or instruct an operator of the current state of the process.

Square Root Extraction

Measurement display using square root extraction to display directly the flow from differential pressure measurements using, for example, an Orifice or Venturi meter.

Over-Temperature Alarms

Compliant with the FM and DIN 3440 standards the 3216i, 32h8i or 3204i can be used as independent alarm units on ovens, furnaces and other processes. Their role is to provide a back-up to the main PID controller so that in event of a system fault whether it be in the sensor, controller or load they will remove power from the load, typically by cutting out the main heating contactor. Outputs are always configured to be de-energised in alarm therefore ensuring failsafe operation.