Acknowledging Relays; Pump Alternation Control Applications (Altern) - Ametek DDMC Instruction Manual

DDMC Analog Input Process Meter / Controller

Acknowledging Relays

There are three ways to acknowledge relays
programmed for manual reset:
1. Via the programmable front panel function keys
F1-F3 (Example: F3 assigned to ACK).
2. Remotely via a normally open pushbutton wired
to the F4 terminal at the rear of the instrument.
3. One of the digital inputs and the +5 V terminals
on the digital I/O expansion module.
When the ACK button or the assigned digital input is
closed, all relays programmed for manual reset are
acknowledged.
Pump Alternation Control
Applications (Altern)
For pump control applications where two or more
similar pumps are used to control the level of a tank
or a well, it is desirable to have all the pumps operate
alternately. This prevents excessive wear and
overheating of one pump over the lack of use of the
other pumps.
Up to 8 relays can be set up to alternate every time
an on/off pump cycle is completed. The set points and
reset points can be programmed, so that the first
pump on is the first pump off.
Application #1: Pump Alternation
Using Relays 1 & 2
1. Relays 1 and 2 are set up for pump alternation.
2. Relays 3 and 4 are set up for low and high alarm
indication.
Set and Reset Point Programming
Relay Set Point
1 30.000
2 35.000
3 4.000
4 40.000
Pump Alternation Operation
1. Pump #1 turns on when level reaches 30.000,
when level drops below 10.000, pump #1 turns
off.
2. The next time level reaches 30.000, pump #2 turns
on, when level drops below 10.000, pump #2 turns
off.
3. If the level doesn't reach 35.000, pump #1 and pump
#2 will be operating alternately.
4. If pump #1 cannot keep the level below 35.000,
pump #2 will turn on at 35.000, then as the level
drops to10.000, pump #1 turns off, pump #2 is still
running and shuts off below 5.000.
5. Notice that with the set and reset points of pump #2
outside the range of pump #1, the first pump on is the
first pump to go off. This is true for up to 8 alternating
pumps, if setup accordingly.
6. Relay #3 will go into alarm if the level drops below
4.000 and relay #4 will go into alarm if the level
exceeds 40.000.
7. Adding the 4 external relays, expansion module
allows using the 4 SPDT internal relays for pump
alternation and the 4 SPST external relays for high,
high-high, low, and low-low alarm indication.
Application #2: Pump Alternation
Using Relays 3 & 4
1. Relays 1 and 2 are set up for low and high alarm
indication.
2. Relays 3 and 4 are set up for pump alternation.
Set and Reset Point Programming
Set
Relay
Point
1 495
2 7500
3 7000
4 6000
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Instruction Manual
Reset Point Function
10.000 Controls
pump #1
5.000 Controls
pump #2
9.000 Controls
low alarm
29.000 Controls
high alarm
Reset
Function
Point
750 Controls low alarm
6900 Controls high alarm
900 Controls backup
pump
1000 Controls main pump