LF-TD-TA air humidity and temperature transmitter

Analogue air humidity and temperature measurement up to 60 °C

The LF-TD-TA is the simplest transmitter of the LF-TD series: it measures the relative humidity and the temperature of air up to 60 °C and delivers both quantities as 4-20 mA signals. It has no display and no digital interfaces - it is meant for installations where the reading is collected by a controller, a data logger or a building automation system anyway.

Typical applications are laboratory, air-conditioning and drying technology, the timber, food and feed industries, construction, printing and papermaking, agriculture, biotechnology and the pharmaceutical industry.

Stainless steel probe with a replaceable cap

The stainless steel sensor tube, 12 mm in diameter and 125 mm long, passes through the wall of a room, a chamber or a duct. The sensor cap is screwed on and replaceable - there is a choice of sintered stainless steel (art. no. 10249) and nickel-plated sintered bronze (art. no. 13799).

Two 4-20 mA outputs and a 12 to 24 VDC supply

Humidity leaves the device as a 4-20 mA signal scaled 0 to 100 %, temperature as a second 4-20 mA signal scaled -20 to +60 °C. The supply falls within 12 to 24 VDC, so the device works with a typical cabinet power supply. The permitted operating temperature of the electronics is -20 to +60 °C.

When to choose a stronger model of the series

The LF-TD-TA is calibrated to ±3 % for humidity and ±0.6 °C for temperature. Where ±2 % and ±0.3 °C, a display on the device or a digital interface are needed, the right choice is the LF-TD 60. For temperatures above 60 °C there are the LF-TD 90, LF-TD 120, LF-TD 150 and LF-TD 180.

Factory calibration

The transmitter is calibrated at the factory. The calibration accuracy is ±3 % over the range of 10 to 90 % relative humidity and ±0.6 °C over +10 to +60 °C. A factory calibration certificate with an adjustment report is supplied on request (art. no. 10403), and the sensor can be checked in place with the calibration device for tube probes (art. no. 10006) together with certified ampoules.

Advantages The capacitive humidity sensor keeps its accuracy over years of operation and withstands the usual contamination and contact with many chemicals. The stainless steel tube with a replaceable cap lets the sensor be matched to the dust load at the measuring point. the simplest and least expensive transmitter of the LF-TD series 4-20 mA outputs for humidity and temperature stainless steel probe Ø 12 x 125 mm 12 to 24 VDC supply aluminium housing with mounting holes replaceable sensor caps to choose from

Technical data

Scope of delivery

LF-TD-TA with a 1.9 m connecting cable.

Extended accessories

• Art. no. 10249 - sintered stainless steel sensor cap with a sintered filter, for high temperatures and demanding conditions
• Art. no. 13799 - nickel-plated sintered bronze sensor cap
• Art. no. 12456 - drip guard for LF-TD transmitters
• Art. no. 10006 - calibration device for tube probes
• Art. no. 10352 - certified calibration ampoules, set of 5 at 50 % relative humidity
• Art. no. 10005 - certified calibration ampoules, set of 5: 2 × 35 %, 1 × 50 %, 2 × 80 % relative humidity
• Art. no. 10403 - factory calibration certificate with an adjustment report
• Art. no. 12011 - special version, flat rate to order, regardless of the quantity ordered

For similar applications we also recommend the LF-TD 60 with a more accurate calibration, an optional display and a digital interface, and the LF-TD-E with an Ethernet socket.