The XL7 on-line viscometer provides continuous real-time viscosity measurement with high resolution, high repeatability and virtually unlimited range. Any model can be supplied in an intrinsically safe version certified to IEC Ex ia IIC for Hazardous Areas. Outputs include a fully-configurable 4-20mA analogue output and an RS485 serial data link for remote viscosity monitoring/control. The high-temperature HT2 model can be used at up to 450oC without special cooling, while high-pressure models are rated at 1380 bar or greater. Measurements are unaffected by variations in flow rate or by the presence of suspended solids or gases. The sensor is an all-welded construction which can be mounted at any location and in any orientation using any process fitting. The XL7 is factory-calibrated to certified viscosity standards traceable to NIST and requires no on-site calibration. As there are no moving parts, maintenance is negligible and no spares or accessories are required.