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Copyright © 2001, MCB UP Limited
Remote probe takes the heat off humidity measurement
Remote probe takes the heat off humidity measurementKeywords: Humidity, Probes
Instrumentation specialist Lee-Dickens has introduced the HP300, a low-cost relative humidity (RH) probe with a remote interchangeable head for raised temperature or dirty environments (see Plate 8). The probe can be used over a temperature range of –40°C to +85°C.
Most RH probes are mounted with the sensors and electronics in the one enclosure. For the HP300, having a remotely connected sensor head means that the electronics, which have a working range of –10°C to +65°C, can be mounted in a cabinet or control room, with the sensor head itself in the extreme temperature environment. Another use for a remote RH probe is in dirty conditions: apart from any adverse effects on the electronics, a remote detachable head makes cleaning much easier.
Plate 8 The HP300 low cost humidity probe with remote interchangeable head
The HP300 electronics unit is DIN-rail mounted and contains the probe's supply and signal conditioning. This is connected to the probe using a three wire cable. The probe is housed in a plastic polycarbonate enclosure with either a plastic cage or a sintered bronze guard that can be unscrewed to reveal the RH sensor. The head is also designed to take the standard Lee-Dickens 0 per cent and 75 per cent field calibration capsules.
The HP300 system has a measuring range of 0 to 98 per cent RH and is accurate to ±2.0 per cent, making it suitable for humidity measurement in a range of applications such as chemical storage, pharmaceutical processes, drying processes and environmental test chambers.
Contact: Lee-Dickens Ltd, Desborough, Kettering, Northants, NN14 2QW, UK. Tel: +44 (0)1536 760156; Fax: +44 (0)1536 762552.