SECTION 4
Differential Level Measurement Program
Changing the application to Differential Level Measurement Control loads this default
program into memory. In this mode, the transceiver drives two transducers to measure the
difference in levels by subtracting the downstream level from the upstream level. Please see
connection diagram Figure 7 for transducer wiring (Page 8).
The upstream transducer should be chosen to give a positive differential value.
Pr.2.0 Empty Distance
2.000m
Pr.4.0 Blanking 0.500m
Pr.8.1.1.2 R1 Reset 0.050m
Stop rake
Pr.8.2.1.1 R2 Set
0.600m
Pr.8.2.1.2 R2 Reset
0.550m
Pr.8.1.1.1 R1 Set 0.150m
Start rake
Pr.3.0 Operational Span
0.500m
RAKE CONTROL
Flow
UPSTREAM ALARM
This default program is created to do the following:-
Start rake when differential reaches 0.15m.
Stop rake when differential falls to 0.05m.
Maximum differential 0.50m.
Alarm if level on upstream side exceeds 0.60m.
4-20mA output proportional to differential.
On Loss-of-Echo energise alarm and switch rake on.
This program can be easily modified to suit the required application. You should delete from
this program any unwanted entries (e.g. Relay 2 settings).
Parameter Default Description
number Setting
2.0 Empty Distance = 2.000 The distance from bottom of channel to
transducers in metres.
3.0 Operational Span = 0.500 The maximum differential span.
4.0 Blanking = 0.500 Blanking zone.
5.0 RateOfChange = 1.000 The maximum rate of change of level in
metres/minute.
8.1 Rly1 Options = 8.1.2 Relay 1 Differ. Control Relay 1 designated for differential control.
8.1.2.1 Relay 1 Set = 0.15 Relay 1 energises at differential 0.15m to start
rake.
8.1.2.2 Relay 1 Reset = 0.05 Relay 1 de-energises at differential 0.05m to
stop rake.
8.2 Rly2 Options = 8.2.7 Relay 2 Upstream Alarm Relay 2 to alarm on an upstream level.
8.2.1.1 Relay 2 Set = 0.60 Relay 2 de-energises at 0.60m high alarm.
8.2.1.2 Relay 2 Reset = 0.55 Relay 2 energises at 0.55m to clear high alarm.
Ref: MINIFLEX LR MANUAL Rev. 0 41
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