FCD25 is generally useable for monitoring mA signals. The signal can be fed from a standard 2-wire sensor with 4-20 mA output or from other instruments with current input, for instance FPA38.
The analog input is a current input, which can be set up to either a 0-20mA or 4-20mA. Further more the input can be scaled, so tha the instrument displays 100% down to 10mA.
For unversal applicability FCD25 can be configured to both positiv and negativ logic at the digital indgange. Via a parameter the inputs are set actively high or active low. By positiv logik input voltages from 5-30VDC are accepted. By negativ logic the input is connected to Gnd-, for instance via a switch.
The module contains 2 relays - one for each limit. The relays are both end contacts, but can via a parameter be inverted independant of each other. Alarm can be reset with the ‘Mode’ botton or input S1.
The device contains 2 independant limits. All settings belonging the individual limit can be set independant of the other limit. Each limit can be set as a max. eller or min. limit. The limit value is set in %. With the input S2 the monitoring can be blocked.
Start- up timer
The start-up timer can be used when a process is unstable and no alarm under start-up is wanted. It is activated when the measuring exceeds around 5% of the measuring range. If the timer is set to 0, there will be a monitoring without the use of start-up timer.
To each limit there is a reaction timer to prevent alarm by short exceeds of the limit value.
Hysteresis can be activated at both sides. The hysteresis band is allways over a min.-limit and under a max.-limit. If the hysteresis function is used, an internal auto-resetf unktion is activated. If a hysteresis function is used by a min.- limit, and the input signal reach under 5% of the measuring range the alarm must allways be reset.
If the hysteresis is OFF, the alarm must also allways be resat. The alarm is reset by activating ‘Mode’, or by activating input S1.