get a quote
LFT720 flange-mounted transmitter consists of the LFT710 Differential Pressure Transmitter and a welded level flange. The flange and the sensor are filled with silicone oil to transfer the pressure, avoiding the measurement influence of the measured medium through the pilot tube. The Influence on the measurement caused by the measured medium passing through the pilot tube includes crystalline solidification vaporisation (boiling), condensation, fractionation (heavy change), etc. lt is used to measure the pressure of liquids, gases or steams and then convert it into a 4-20mA signal. The measurement principle is the same as LFT710 DP Transmitter. The only difference lies in the pressure transfer route, pressure is firstly transmitted through the diaphragm of the level flange and the filled oil, then through the transmitter body and finally reach the measuring sensor.
Pressure range is calibrated based on the standard zero point, stainless steel 316L diaphragm, filed liquid is silicone oil.
1)Pressure calibration reference accuracy
| Including linearity, hysteresis and repeatability from zero point | |||
| Linear output accuracy | TD≤10 | ±0.2% | Standard range: 40kPa, 250kPa, 1MPa, 3MPa |
| 10<TD≤100 | ±0.02TD% | ||
| Note: TD is range turn down ratio. When |URV|≥|LRV|, TD=URL/|URV|; when |URV|≤|LRV|, TD=URL/|LRV | |||
2) Power supply influence
When the power supply voltage varies within 12~36 VDC, if zero point and span variation not exceed ±0.005%*URV per
voltage, the influence can be ignored.
1) Range
| Range/Upper and lower range limits(URL&LRL) | kPa | Range ratio TD | |
| C | Range | 1~40 | 1~40 |
| URL & LRL | -40~40 | ||
| D | Range | 2.5~250 | 1~100 |
| URL & LRL | -250~250 | ||
| E | Range | 10~1000 | 1~100 |
| URL & LRL | -500~1000 | ||
| F | Range | 30~3000 | 1~100 |
| URL & LRL | 500~3000 | ||
2) Range selection
Within the upper range limit (URL) and lower range limit(LRL), you can adjust the TD value within the allowable range to select the range. For example, if URL and LRL -40~40kPa, then adjust the TD value to 10 and select the output of 0~4kPa or -4~4kPa. To ensure accuracy, the TD value should be assmall as possible, generally within 10.
3) Zero point setting
Zero and Span can be adjusted to any value within the measuring range in the table, as long as calibrated span >minimum span.
4) lmpact of the installation position
The level flange can be mounted in any position. The best condition is to keep the flange in a vertical position, and the offset caused by positional deviation can be corrected by zero clearing.
5) Output
| Signal | Type | Output method |
| 4~20mA | linear | two-wire |
| 4~20mA+HART | linear | two-wire |
| RS485 | linear | four-wire |
7) Response time
Total damping constant time: Equal to the sum of the damping constants time of the electronic circuit components and the sensing diaphragm box.
Electronic circuit components damping time: 0-60S adjustable
Sensing diaphragm box damping time: ≤0.2S
Start-up time after power failure: ≤5S
Data recovery to normal use time: ≤2S
8) Environmental temperature
| ltem | Operation Conditions |
| Ambient working temperature | -20~70℃ with display |
| Storage temperature | -40~85℃ |
| Ambient humidity temperature | 5-100%RH@40℃ |
| Protection level | IP65 |
| Hazardous occasions | ExdIICT6 |
| Measuring diaphragm enclosure | Stainless steel 316L |
| Diaphragm | 316L, Hastelloy, Tantalum, FEP, PFA, PTFE |
| Process flange | Stainless Steel 304, Stainless Steel 316L |
| Nuts and bolts | Stainless steel (A4), colored zinc |
| Sealing ring | NBR, FKM, EPDM |
| Transmitter housing | Aluminium alloy material |
| Housing seal | Nitrile rubber (NBR) |
| Nameplate | Stainless steel 304 |
Log in 
English 
