Infrared sensors use an optical system to collect infrared energy from a measured target area. This energy is used to calculate the target surface temperature. In many industrial and laboratory settings, there are often application issues that interfere with the amount of infrared energy collected by the sensor, including: emissivity variation, misalignment, intervening optical obstructions and stray reflected infrared energy.

The PRO Series dual- and multi-wavelength sensors offer ESP to improve and simplify the management of these application issues. The goal of ESP is to enable out-of-the-box ‘aim-and-read’ capabilities for even the most demanding applications. Unique ESP features include:

• System status messages provide useful information for operation verification.
• Five measured parameters enable the sensor to effectively characterize a wide range of application conditions (See Table below). Each measured parameter may be viewed on the sensor’s displays or sent elsewhere via programmable outputs and alarms.
• Pre-programmed,application-specific ESP Models automatically recognize and compensate for a wide range of application conditions. ESP parameters can be easily adjusted for custom application requirements or for fine-tuning of an existing ESP Model.
• A text-based menu makes it easy to view and adjust parameters in the system. If adjustments are required, no manual or special training is required to translate obscure programming codes.

All combined, these innovative features enable the PRO Series dualand multi-wavelength sensors to outperform traditional noncontact temperature sensors for all but the simplest applications.

PRO Series Measured Parameters
Parameter	Description	Troubleshooting Procedure
Ambient Temperature	The ambient temperature inside the sensor is measured to verify that the sensor is within its specified ambient operating limits. A status message is displayed when ambient limits are exceeded.	• Move the sensor to a cooler location • Shield the sensor from the heat source(s) • Add a water- or air-cooling accessory • Convert to a fiber optic style sensor
Signal Strength / Emissivity	The signal strength value is a measure of effective emissivity. When the sensor field of view is filled, with no obstructions or background influences, this value represents the emissivity of the measured surface.	Low Signal Strength & Signal Dilution Readings • Clean the sensor lens / window • Verify sensor alignment • Eliminate optical obstructions     High Signal Strength & Signal Dilution Readings • Eliminate reflections from background sources • Eliminate a high temperature interference
Signal Dilution	Signal dilution is a relative measure of the infrared energy emitted by a target. A signal dilution factor of 500:1 indicates that the sensor is measuring 500 times more infrared signal than is required to make a reading.
Unfiltered Temperature	The measured target temperature with no signal conditioning filters applied. It can be viewed simultaneously with the filtered temperature to better understand the measurement conditions.	• If this value is particularly unstable, it many indicate that some abnormal conditions exist.
Filtered Temperature	The measured target temperature with the signal conditioning filters applied.	• If this value is unstable then identify the interference via an association, or adjust signal conditioning (time averaging, peak hold, or ESP filtering) to obtain an acceptable reading.

ESP Filtering Assures the Validity of Measurements When Severe Interference Exists

It is not always possible to eliminate interference sources. But with Williamson’s unique ESP filters for signal strength and signal dilution, it is possible to overcome persistent application interference.

The PRO Series dual- and multi-wavelength sensors continuously measure signal strength and signal dilution. Because each application has a characteristic range of acceptable values for these parameters, these measurements provide the sensor with valuable information about application conditions.

By setting the ESP filters for signal strength and signal dilution to the characteristic range of an application, the sensor can automatically recognize valid and invalid application conditions and respond appropriately. ESP filters can be pre-programmed for specific applications, and easily adjusted in the field from the text based menu system for unique applications and ad hoc troubleshooting procedures.

There are two possible responses that the sensor can provide to an invalid operating condition:

• The sensor can “turn off” and display a status message that indicates which ESP Filter is out of range.
• An advanced peak hold feature can display and hold the last valid temperature measurement before the invalid condition occurred.

The end result of the ESP filters is that the sensor will only display temperature values that are accurate and reliable. Thus, ESP filters enable more reliable temperature monitoring to help improve process quality, control, and productivity.

One example where ESP Filtering is used to assure valid readings is the temperature measurement of a molten iron stream. In this application, heavy smoke, sparklers, and reflections often make measurement extremely difficult. The three graphs illustrate how advanced ESP Filters are used to recognize changes in application conditions and enable the sensor to respond appropriately for more accurate and reliable temperature measurements.

Other Resources to Download:

PRO SERIES WITH ESP BROCHURE