Functional Principle; Basics - KPM PROCESS SENSORS PSC-S55N Operation Manual

PSC-55 Pyrometer Series Operation Manual

Functional principle

Basics

The PSC-S55N/ PSC-G55N/ PSC-GE55N/ PSC-SR55N provides an RS-485
interface. The devices are bus-compatible and use the Modbus RTU protocol. Please
read the document "Communication Description Modbus RTU, for detailed
information about Modbus RTU. Connect the pyrometer with the additional available
RS-485 module (please refer chapter Accessories) to a computer to adjust emissivity,
sub temperature range, data storage settings, response time and further parameters to
the application.
The Model PSC-SR55N is a digital 2-color / ratio pyrometer for non-contact
temperature measurement. It measures the infrared radiation in two adjacent
wavelengths and determines the temperature value. This technique offers the
following advantages compared to standard 1-color pyrometers:
 The temperature measurement is independent of the object's emissivity in
wide ranges and is unaffected by dust and other contaminants in the field of
view.
 The measuring object can be smaller than the spot size.
 Measurements through dirty viewing windows are possible up to a certain
contamination.
 The pyrometer can also be switched and used in 1-color mode (Single
detector mode).
The PSC-S55N/G55N/ PSC-GE55N/ PSC-SR55N operate in a 4-wire configuration.
2 wires for the power supply and 2 wires for transmitting the analog measuring signal.
The infrared radiation of the measured object will be collimated via the IR sensor's
lens onto the detector and converted to an electrical signal. This signal will be digitally
processed and transferred in the standard temperature linear signal of 0/4 to 20 mA.
The milliamp output signal is specifically suitable for bridging great distances
(Approximately 1 mile). In current operation, the influence of electromagnetic
interferences on the measuring signal is minimized (low resistance receiver input)
Accessory devices like a digital display or a controller, that convert the output signal
of 0/4 mA to 20 mA, can be integrated in the current loop. Please note that the loop
resistance / maximum burden ��
Additional equipment like a digital display or a controller that processes the output
signal 0/4 to 20 mA must be connected in series between pin L (I+, green wire of the
optional connection cable) and pin B (I–, yellow wire) of the pyrometer.
Find detailed information concerning basics of non-contact temperature measurement
technology in references /1/-/3/.
Every real body emits according to its surface temperature infrared radiation which
intensity is mostly less than which of an ideal radiating black radiator of the same
temperature. The ratio of the radiations is characterized by emissivity ε. Emissivity
charts can be found in citation /4/.
is 500 Ω.
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