MPE SC2000 - Page 14

ALTERNATION SEQUENCE MODE
FIXED ALTERNATION Parameter P.16 = 5
13
Notes:
1. This sequence is used when no alternation is required and when pump 1
should normally be lead pump. Other pumps may be made lead by setting
Parameter P.39.
2. Discrete Inputs programmed as Pump 1-4 Disable inputs may be used to
disable pumps.
3. Discrete Inputs programmed as Call Pump 1-4 Last inputs may be used to
assign pumps to standby status.
4. Discrete Inputs programmed as Sequence Inputs 1-4 may be used to set the
lead pump.
5. Parameter P.39 may be used to set the lead pump.
6. The Pump Stop Mode (Parameter P.17) has no effect on this sequence.
7. Automatic Alternation Enable/Disable (Parameter P.18) has no effect on this
sequence.
8. The External Alternation feature will not function when using this sequence.
9. If connected to a SCADA system, the lead pump position may be set by
writing to Register 40022 (Same as Parameter P.39).
10. Time Based Alternation using Parameter P.51 will not function when using
this sequence.
Notes:
1. This sequence is used in stations where there is a significant difference in
the size of the pumps, and when only one pump is to be allowed to run at a
time. When there is a need for more pumping, the smaller pump is turned
off and the next larger pump is called to run. As the need for pumping de-
creases, the larger pump is turned off and a smaller pump is called to run in
its place (provided the Off Levels are staggered).
2. The Lag Pump Delay operates to give the check valve of the pump being
turned off time to close before another pump is called to run.
3. Discrete Inputs programmed as Pump 1-4 Disable inputs should be used to
disable pumps that are not able to run. It is critical that the largest pump in
the group, have some type of pump fault logic connected to the respective
Pump Disable discrete input.
4. Discrete Inputs programmed as Call Pump 1-4 Last will not function when
using this sequence.
5. Discrete Inputs programmed as Sequence Inputs 1-4 will not function when
using this sequence.
6. Parameter P.39 has no effect on this sequence.
7. The Pump Stop Mode (Parameter P.17) has no effect on this sequence.
8. Automatic Alternation Enable/Disable (Parameter P.18) has no effect on this
sequence.
9. The External Alternation feature will not function when using this sequence.
10. The On Generator (Parameter P.15) has no effect on this sequence.
11. Time Based Alternation using Parameter P.51 will not function when using
this sequence.
STEPPED ON/OFF SEQUENCE
Only One Pump Runs at a Time Parameter P.16 = 6