Additional Technical Data; Electrical Settings - Culligan MP97 Manual

ADDENDUM CONDUCTIVITY INPUT

ADDITIONAL TECHNICAL DATA

As already mentioned in the first part of the manual, we confirm that electronic precision is better than 0.3% and
that repeatability is better than 0.2% on F.S., thermocompensation excluded (resistive calibration).
Thermocompensation is carried out by an NTC 10K. This component is available either as a separate element from
the cell (NTCS) or included in the CCK 5 TC cell (further information is available in the relative documentation).
The T thermocompensation coefficient is fixed at 2%/°C. This value is suitable for applications with most types of
water. For applications on water containing strong acids or alkalis and whose coefficient is most certainly not
2%/°C, please contact our technical department for information. The addition of thermocompensation adds an error
of less than 1% of the F.S. for temperatures between 15 and 75°C.
ELECTRIC CONNECTIONS
PANEL VERSION
The input from the 2-electrode cell is provided on the 5-pin extractable terminal strip. The pins
relative to the cell are numbered 21 and 22; the pin relevant to the shielded cable braiding, if
used, is 20. The use of a shielded cable is recommended for sensitive ranges (low
conductivity). If shielded cable braiding is used, this must be connected on the µP 97 side only.
The input from the NTC 10K temperature sensor is provided at terminals 23 and 24.
The µP 97 is supplied with a 10 K resistence on terminals 23 and 24 to simulate a value of
25°C approx. If thermocompensation is required, this resistence must be removed and
replaced with the NTC10K. It is important that the NTC10K is immersed in the measurement
liquid close to the electrode or at least at the same temperature. As already mentioned in the
first part of the manual the signal cables must be kept separate from the power cables.
WALL MOUNTING VERSION
The input from the 2-electrode cell is provided on the 5-pin extractable terminal strip. The pins
relative to the cell are numbered 14 and 15; the pin relevant to the shielded cable braiding, if
used, is 16. The use of a shielded cable is recommended for sensitive ranges (low
conductivity). If shielded cable braiding is used, this must be connected on the µP 97 side only.
The input from the NTC 10K temperature sensor is provided at terminals 12 and 13.
The µP 97 is supplied with a 10 K resistence on terminals 12 and 13 to simulate a value of
25°C approx. If thermocompensation is required, this resistence must be removed and
replaced with the NTC10K. It is important that the NTC10K is immersed in the measurement
liquid close to the electrode or at least at the same temperature. As already mentioned in the
first part of the manual, page 5, the signal cables must be kept separate from the power
cables.
PERMANENT PROGRAMMING
Parameters 20, 21 and 22 are set automatically by the microcontroller which recognizes the position of the dip-
switch S3 situated on the master card. The strips S6, S7 and S8 on the input card are positioned in accordance
with the position of S3.

ELECTRICAL SETTINGS

A test for checking that the instrument is working properly can be carried out with a resistive simulator connected in
place of the cell. With infinite resistence the instrument's display will indicate 0 (apart from any offsets that have
been memorized). The resistence to be inserted in place of the cell, to simulate a certain conductivity value, is
given by the following formula:
1
Rcell = ────────
(Cond * K)
NOTES:
Keep in mind the amplification factor (GAIN) set in the µP 97 to check the correct value on the display. The
amplification factor can be seen by pressing the key [ + ].
The temperature must be 25°C or a resistive value of 10 K must reach the terminals 22 and 23.
M003-23 - Rev. 03 - 05/2009

1
MΩ = ───--──────

(µS/cm * cm)

Rcell = simulation resistance

Cond = cond. to simulate

K = cell constant
Microprocessore µP97
NTC
CELL
10K
REF
.
20 21 22 23 24
NTC
CELL
10K
REF
.
12 13 14 15 16
37