Double limit switch FCD25
- Programmable double limit switch
Analogue input 0(4) - 20 mA
Selectable min- or max limits
Start-up and reaction timer
Supply voltage 24 VDC
Made in accordance with the CE and EMC regulations
FCD25 is a double limit switch for monitoring of current signals, f.inst. from 2-wire transmitters with 4-20 mA output or other units with current output.
The analogue input is programmable for either 0-20 mAor 4-20 mA. The input range is adjustable too, down to 10 mAfor 100% input range.
The digital inputs are programmable for either positive or negative logic. The inputs are programmed for either active low or active high.
At positive logic, input signals from 5-30 VDC are accepted.
At negative input, the input is connected to ground f.inst. with a contact or an NPN output from a sensor.
The unit is supplied with 2 relays, one for each limit.
Both relays have NO-contacts, and both of them are programmable for either activation or release, when the set limit is exceeded.
The alarms can be reset with the "Mode" button or input "S1".
The unit have two independent setpoints, programmable as either min. or max. setpoint.
The setpoints are selected as a percentage of the range.
It is possible to cancel the monitoring with the input S2.
Start up timer
The start up timer is used if the start-up of a process is unstable and you do not want an alarm during start-up.
It is activated when the input signal exceeds approx. 5 % of the metering range.
If the start-up timer is set at 0, this function is cancelled.
For each setpoint you can program a reaction delay in order to avoid alarm in case of only a short exceeding of the setpoint.
The hysteresis can be used on both limits.
The hysteresis band is always above a min-limit and under a max-limit.
If the hysteresis function is used, an internal auto-reset function is used.
If you use the hysteresis at a min. setpoint, at the input signal goes to zero, you can reset the alarm by pressing the "Mode" button or activate input S1.