- Emerson Electric Co. Computer Monitor User Manual

Page 32
MSL600
Installation, Operation & Maintenance Manual
IP262/Z0, Rev. AB
February 2012
7.6 Relay parameters
The following parameters are used to program the 2 available relays RL1 and RL2, which are controlled by the
sludge blanket level. The mode of relay RL3 is fixed to fault indication.
Note: A full menu structure is shown in section 11.
P RL1 RL2
Mode 410 420
On Point 411 421
Off Point 412 422
Min ON 413 423
Max ON 414 424
Min OFF 415 425
Table (B): Relay Parameter numbers
7.6.1 Relay RL1 mode (P410) and RL2 mode (P420)
The mode of operation, or function, of the relay can be selected from a list:
A) Alarm ............................................................ see page 32
B) Fault ............................................................. see page 33
C) Set Point ....................................................... see page 33
D) De-sludge ..................................................... see page 33
E) On ................................................................. see page 33
F) Off ................................................................. see page 33
G) None ............................................................. see page 33
H) Slg lev limits (Sludge Level Limits) ............... see page 33
i) Temp OL (Temperature Over Limits) ............ see page 33
7.6.1.1 Alarm mode (relay RL1 and RL2 parameters P540 to 552)
There are several alarms which can be assigned to a relay. When an alarm condition occurs it may be signalled
by relay, current, both relay and current, or not at all. Alarm conditions are listed below:
x Out of Limits - P540
The sludge blanket level is outside the limits set in the relay on and off point parameters
x mA o/p Sat. (Current Saturated) - P541
The current output is outside the limits set in the current output parameters.
x Memory Filling - P542
The logging memory is filling. This alarm condition is activated when the remaining memory is less than the
percentage programmed by the user in ‘Low Mem Alarm’ P593.
x Digital Input - P543
If the digital input is active then the relay indicates alarms.
x Max Retries - P544
If at the end of a de-sludge operation the start condition is still present for a programmed number of retries
then the relay alarms.
x Xdr Tilted - P550
An alarm can be activated after the transducer has been out of water for a user-programmed length of time.
x Dirty S-nat - P551
If the supernatant gives a high degree of returned echo (indicating a significant number of suspended
particles) then an alarm can be activated.
x Noise Alarm - P552
An alarm is activated if the background noise exceeds the pre-set limit set in parameter P622.