aran_v02 or higher
NRF-100_KM Rev. : 1.0
16 / 04 / 2002
01 / 12 / 2002
In order to calibrate the transmitter, you must use the loop
current meter. It should read currents in the range of 1.00
to 25.00 mA, with a resolution of .01 mA. Using a meter
of less resolution will somewhat reduce the calibration
accuracy. To calibrate the instrument :
1.
Remove enclosure (head) cover.
2.
Connect the loop current meter as per instructions in
WIRING section(Fig. 3).
3.
The loop current should now be in the range of 1.5
mA to 38 mA, which is normal at this point.
Three calibration procedures are described. Follow the
one which fits your application. Note the following defini-
tions used in the calibration procedures, referring to Fig 4.
L = the level of material which corresponds to 4.00 mA of
loop current, i.e., the 0 %
L1 = a material level higher than L
H1 = a material level higher than L1, but less than H.
H = the level of material in the vessel which corres-
ponds to 20.00 mA of loop current, i.e., the 100% level.
Note: To avoid the possibility of a “dead zone”, L must be
at least two ( 2 ) inches above the end of the probe for ( 4)
conductive media and four inches above for non-
conductive media.
CALIBRATION L- H = when material in tank can be set
to L ( 0% ) and H (100 % ).
CALIBRATION L - H1 = when material in tank can be set
to L (0%) and H1 (less than 100 % ).
CALIBRATION L1 - H1 = when material in tank can be
set to L1 (greater than 0 % ) and H1 (less than 100 % ).
NOTE: Calibration procedure L-H gives the most
accurate results and is the recommended procedure in
all cases.
All wiring between the power supply and the transmitter
should be done with 18 AWG to 22 AWG shielded twisted
pair. The connection is made at the terminal strip within
the transmitter enclosure.
CAUTION: Units are designed to operate on the 12 to
36 VDC power only. Application of 110 VAC will destroy
the instrument.
1. Make sure the power source is turned off.
2. Pull power supply wires through conduit connection.
3. Connect the positive supply wire to the ( + ) terminal,
and the negative supply to the ( - ) terminal.
Note: Leave shield unattached at transmitter.
Connect the shield to ground at the power source.
4.
Replace the transmitter enclosure (head) cover until
time to calibrate.
5.
Connect positive supply wire to the positive terminal
of the transmitter. See Fig. 3.
6.
Connect the loop current meter in series with the
negative supply wire as follows:
a. Negative transmitter wire to positive meter
terminal. See Fig. 3.
b. Negative meter terminal to negative power
source termianl. See Fig.3.
7.
Turn ON the power. The meter may read anywhere
on the scale at either end. This is normal until calibra
tion has been completed. Proceed to the calibration
Instructions.
Fig. 3
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