EM3701 - application examples
Tank systems
Fig.135: EM3701 application example: filling level of tanks The filling level of a tank system can be checked using a differential pressure measurement. In sealed tanks the gas phase exerts an additional pressure (P1) on the liquid in the tank. This effect is compensated by differential pressure measurement. Based on a tank linearization table, the filling level can be calculated in the PLC and displayed. The level can be controlled by introducing lower and upper limit values.
- Measuring the pressure difference as an indicator for the filling level
- Controlling the filling level of tanks and topping up if the level falls below a level defined by limit 1 (lower limit) or draining of a limit 2 (upper limit) is exceeded.
- Determining and displaying the filling level via PLC
- No additional pressure gauges, switches and associated connection equipment are required
Measurement result | Limit 1 | Limit 2 | Message | Meaning |
|---|---|---|---|---|
Limit1 < P < Limit2 | 1 | 2 | Status message (green) | Filling level OK |
P < limit1 < limit2 | 2 | 2 | Warning (yellow) | Level is below the minimum filling level (limit 1) |
P > limit2 > limit1 | 1 | 1 | Warning (yellow) | Level is above the maximum filling level (limit 2) |
Filter systems, pipe constrictions
Fig.136: EM3701 application example: filter systems, pipe restrictions The pressure difference of the transport medium is the driving force in a filtration. The difference between the inlet pressure P1 and the outlet pressure P2 increases with increasing soiling of the filter. Increased soiling results in increasing energy costs and increasing probability of failure. The filter condition should therefore be clearly displayed at all times.
- Measuring the pressure difference as an indicator for the degree of soiling
- Assessing the degree of soiling via the PLC
- Monitoring the filter status via limit 1 (warning) and limit 2 (alarm)
- Issuing of messages
Measurement result | Limit 1 (Index 0x6000:03) | Limit 2 (Index 0x6000:05) | Message | Meaning |
|---|---|---|---|---|
P < limit 1 < limit 2 | 2 | 2 | Status message (green) | Degree of filter soiling OK |
Limit 1 < P < limit 2 | 1 | 2 | Warning (yellow) | Increased degree of soiling, filter should be changed. |
P > limit 2 > limit 1 | 1 | 1 | Alarm (red) | Change filter |