Emerson Process Management MSL600 manual Relay RL1 mode P410 and RL2 mode P420

	Installation, Operation & Maintenance Manual
MSL600	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

7.6.1Relay 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

7.6.1.1Alarm 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:

￿Out of Limits - P540

The sludge blanket level is outside the limits set in the relay on and off point parameters

￿mA o/p Sat. (Current Saturated) - P541

The current output is outside the limits set in the current output parameters.

￿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.

￿Digital Input - P543

If the digital input is active then the relay indicates alarms.

￿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.

￿Xdr Tilted - P550

An alarm can be activated after the transducer has been out of water for a user-programmed length of time.

￿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.

￿Noise Alarm - P552

An alarm is activated if the background noise exceeds the pre-set limit set in parameter P622.

Page 32