Videographic Recorders
SM1000 and SM2000
3 Logic Configuration
18
IM/SM2000ADV
Issue 7
3 Logic Configuration
3.1 Logic Equation Description
3.2 Worked Example – Reservoir Level Control –
Fig. 3.1
Note.
12 logic equations
Up to 6 operands and 5 operators per equation
OR/AND/NOR/XOR/NAND/NOT operators – see
Table 3.1 overleaf
Can combine internal and external digital signals – i.e.
alarms, digital inputs, other logic equation results and
real time events (timer option).
Note.
This example uses an optional Hybrid I/O Module in
position D – see Appendix E in the User Guide (IM/SM1000
or IM/SM2000).
Channel 1.1 records the reservoir level, with an
engineering range 0 to 100 feet.
Alarms 1.1A, 1.1B and 1.2A monitor the reservoir
level.
Digital output D6 to drive the control valve from Logic
Equation 1
Digital input D1 to operate the manual override.
Fig. 3.1 Logic Equation Example
Alarm 1.1A set to high process trip at 50 ft
Alarm 1.1B set to high process trip at 80 ft
Alarm 1.2A set to fast rate trip at 10% of range per hour
(10 ft/hr)
Manual override switch:
Connected to (optional) digital input D1
Input Elements
Flow Conditions
Close reservoir control valve if:
Reservoir level >50 feet AND rate of change >10 ft/hr
OR
Reservoir level >80 ft
OR
Manual override switch operated
50
feet
80
feet
Control
Valve
Level Sensor
Relay Output
Alarm 1.1B
Alarm 1.1A
Time
Level
Alarm 1.2A
Rate of
change
> 3m/h
Alarm 1.1A
Alarm 1.2A
Alarm 1.1B
Digital i/p D1
And
Or
Or
Equation
1
result
Manual Overide
Note.
Elements within each equation are calculated sequentially.
