Emerson Rosemount 3308A, Reference Manual

Page: 143 / 226

Table A-1: Maximum Recommended Viscosity and Contamination/Build-up
Probe type Maximum viscosity Contamination/build-up
Single lead 8000 cP
(1)
Build-up allowed
Twin lead 1500 cP Thin build-up allowed, but no
bridging
Coaxial 500 cP Not recommended
(1) Consult your local Emerson representative in the case of agitation/turbulence and high viscous
products.
A.1.4 Measuring range
Table A-2: Measuring Range and Minimum Dielectric Constant
Probe type Maximum measuring range Minimum dielectric constant
(1)
Flexible single lead 55.8 ft. (17 m) 2.0, when distance < 32.8 ft. (10 m)
10, when distance > 32.8 ft. (10 m)
Rigid single lead probe (0.3-in./8 mm) 9.8 ft. (3 m) 2.0
Rigid single lead probe (0.5-in./13 mm) 19.7 ft. (6 m) 2.0
Segmented rigid single lead 32.8 ft. (10 m) 2.0
Flexible twin lead 55.8 ft. (17 m) 2.0, when distance < 32.8 ft. (10 m)
10, when distance > 32.8 ft. (10 m)
Coaxial 19.7 ft. (6 m) 2.0
(1) Minimum Dielectric Constant may be lower than 2.0 if one or more of the following conditions apply:
• Probe is installed in stilling well or chamber.
• Maximum measuring range is not utilized.
• Noise Threshold is manually adjusted to a lower level.
Interface measuring range
The maximum allowable upper product thickness/measuring range is primarily
determined by the dielectric constants of the two liquids.
Typical applications include interfaces between oil/oil-like and water/water-like liquids,
with a low (<3) dielectric constant for the upper product and a high (>20) dielectric
constant for the lower product. For such applications, the maximum measuring range is
limited by the length of the coaxial and rigid single lead probes.
For flexible probes, the maximum measuring range is reduced by the maximum upper
product thickness, according to the diagram below. However, characteristics may vary
between the different applications.
Reference Manual Specifications and reference data
00809-0100-4308 February 2020
Reference Manual 143