Dynasonics TFX Ultra Transit Time Flow Meters - Manual (Page 83)

OTE:
N
An ice bath and boiling water bath are used in these examples because their temperatures are easy to maintain
and provide known temperature reference points. Other temperature references can be used as long as there is a
minimum delta T of 40° C between the two references.
OTE:
N
For maximum RTD temperature below 100° C, the hot water bath should be heated to the maximum temperature for
that RTD.
6. Press Calibrate and the following screen should now be visible. Make sure that the Calibrate Both RTDs at same
temperature box is checked and then enter the temperature to the nearest 0.1° C in the box labeled Reference Temp (deg C).
7. Press Next.
The procedure for step 2 of 2 is similar to step 1 except the second water bath is used.
DAC Va l u e:
Ca l i b r a ted Tem p ( d eg C) :
Ca l i b r a ted Tem p ( d eg F ) :
F i r st Ca l Po i n t
R ef er en c e Tem p ( d eg C) :
R TD 1 R TD 2
Ca l i b r a te R TD 1, o r sel ec t th e c h ec k b o x b el o w to c a l i b r a te b o th R TDs a t th e sa m e
tem p er a tu r e. M a k e su r e th a t th e R TD i s a t a k n o w n tem p er a tu r e a n d en ter th i s
tem p er a tu r e b el o w :
Ca l i b r a te B o th R TDs a t sa m e tem p er a tu r e
R TD C a l i b r a t i o n ( S t e p 1 o f 2 )
OK C a n c e l
1
0 . 0 ° C
3 2 . 0 ° F
3
0 . 0 ° C
3 2 . 0 ° F
Figure 61: RTD calibration (Step 1 of 2)
8. Insert both RTD temperature sensors and the laboratory grade thermometer into the second water bath and allow about
20 minutes for the sensors to come up to the same temperature.
9. Make sure that the Both RTDs at same temperature box is checked and then enter the temperature to the nearest 0.1° C in
the box labeled Temp (deg C).
10. Press OK.
11. Press Download on the System Configuration screen to save the calibration values to the flow meter. After the download is
complete, turn the power off and then on again to the meter to make the newly downloaded values take effect.
REPLACING OR RE-CALIBRATING RTDS
Page 83 March 2014