K-Patents PR-21-S - Manual (Page 42)

36 PR-21-S instruction manual
7. The TEMP value should show the current process temperature.
8. The value and the correct setup of the two mA output signals can be checked
by selecting DESCRIPTION in the Main menu and then mA OUTPUTS in the Description
menu (Section 5.3).
9. If internal relays or switch inputs are used, their settings can also be checked
through the Description menu (Section 5.3).
5.1.2 Calibration check
Wait until normal process conditions occur. The concentration reading is precali-
brated at delivery and a copy of the Sensor calibration certificate is inside the Indi-
cating transmitter. If the diagnostic message is
NORMAL OPERATION but the concentra-
tion reading does not agree with the laboratory results, then consult Section 6.6,
“Calibrating the concentration measurement”.
5.1.3 Testing prism wash
1. Check that the steam or water washing parts are connected (Section 4.2).
2. In the Main display, press MENU . Then press 3 (to give the command SENSOR STA-
TUS ). In this Sensor status display by pressing the soft key WASH . If soft key WASH
does not appear, no internal relay is configured for this purpose.
3. Check the n
D
reading, for a successful wash it must drop below 1.34 during
steam wash and drop to approximately 1.33 during water wash.
Important: Before testing prism wash, check that there is liquid in the pipe in
front of the refractometer sensor.
5.2 Using the Indicating transmitter
The Indicating transmitter DTR receives the refractive index value n
D
and the
process temperature from the sensor(s). Starting from these values, it calculates
the concentration of the process media for display and further transmission. The
DTR can also be programmed to give alarm for high or low concentration. If the
refractometer has a prism wash system, the DTR can control the wash with its
built-in timer.
For information on how to use the Indicating transmitter DTR for configuration
and calibration, see Section 6, “Configuration and calibration”.