Flowserve NRS1-40.1 - Manual (Page 7)

7
Explanatory Notes
– continued –
Function
At regular intervals the control unit NRS 1-40.1 evaluates the data telegram coming from the level elec-
trodes NRG 1x-40, NRG 1x-41.1 and the temperature transmitter TRV 5-40. This data telegram contains:
■ An alarm when the electrode NRG 1x-40 emerges and/or when the electrode insulation
is defective,
■ An alarm when the electrode NRG 1x-41.1 enters into the water and/or when the electrode insulation
is defective,
■ An alarm when the adjusted cut-off temperature is exceeded (temperature transmitter TRV 5-40),
■ The result of the self-checking routine (detection of measured value),
■ The temperature in the electrode terminal box and the casing of the temperature transmitter.
When a level or temperature alarm is raised the safety circuit is interrupted after the de-energizing delay.
The control unit does not lock automatically. This function must be implemented in the following circuit.
The safety circuit will be interrupted instantaneously with the following malfunction alarms:
■ Malfunction in the level electrodes (self-checking negative, temperature in terminal box too high),
■ Malfunction in the temperature transmitter (self-checking negative, temperature in casing too high),
■ Malfunction in the control unit (self-checking negative),
■ Communication malfunction.
The self-testing routine checks the safety functions of the controller, the level electrodes and the temper-
ature transmitter. This self-test is carried out every 3 seconds in the controller and every 10 seconds in all
other pieces of equipment.
An additional self-testing routine checks every 6 hours the de-energizing of the output relays in the con-
troller.
Malfunction messages are updated during each self-checking routine. If there is no malfunction the mes-
sages will be deleted automatically and the safety circuit is closed again. However, if the malfunction still
persists, the malfunction message will remain.
Alarm and malfunction messages are indicated by LEDs, and the signal output is instantaneously ener-
gized.