Culligan MP97 Manual page 29

ADDENDUM pH INPUT
ELECTRIC CONNECTIONS
The signal is received from the electrode by means of a coaxial cable whose length must not exceed 15 - 20
meters. If longer lengths are required, please consult our technical department. Input from the electrode is on the
insulated terminal strip (last two terminals on the right). If you are using separate measurement and reference
electrodes, the reference electrode must be connected to the "shield" terminal (coaxial cable braiding).
PANEL VERSION
Input from the Pt 100 temperature sensor is on terminals 15 and 16. The
P97 is supplied with a 110  resistance on terminals 15 e 16 in order to
simulate a value of 25°C approx. If thermocompensation is required, this
resistance must be removed and replaced with a Pt 100. It is important that
the Pt 100 be immersed in the measurement liquid close to the electrode or
at least at the same temperature. The Pt 100 is often supplied with three
wires (for cable loss compensation). The two, internally short-circuited wires
of the Pt 100 must be connected to the same terminal. As already
mentioned in the main manual, the signal cables must be kept separate
from the power cables. Terminals 17,18 and 19 are not connected.
WALL MOUNTING VERSION
Input from the Pt 100 temperature sensor is on terminals 12 and 13. The P97 is
supplied with a 110  resistance on terminals 12 e 13 in order to simulate a value of
25°C approx. If thermocompensation is required, this resistance must be removed and
replaced with a Pt 100. It is important that the Pt 100 be immersed in the measurement
liquid close to the electrode or at least at the same temperature. The Pt 100 is often
supplied with three wires (for cable loss compensation). The two, internally short-
circuited wires of the Pt 100 must be connected to the same terminal. As already
mentioned in the main manual on 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
recognises the position of the dip-switch S3 situated on the master card (see drawing
on right). If S3 is configured in a different way from that illustrated, we cannot
guarantee that the instrument will work correctly.
ELECTROCHEMICAL SETTINGS
If thermocompensation is required, the PT100 must be immersed in a buffer solution in order to take on its
temperature.
1. Wash the electrode in distilled water.
2. Immerse the electrode in a 7.01 pH buffer solution.
Press the [ CAL ] key  << CAL >> appears on the display.
3.
Press the [ - ] key  instead of displaying the old value, the P 97 displays the buffer value of 7.01
4.
(recognised automatically), flashing.
5. Press the [ + ] key to increase the setting.
6. Press the [ - ] key to decrease the setting.
7a. Press the [ CAL ] key to confirm the new setting.
7b. Press the [ NEXT ] key to retain the preceding setting in memory (the setting is lost however).
8. Wash the electrode with distilled water.
9. Immerse the electrode in a 4.01 pH buffer solution (or 9.01)
Press the [ CAL ] key  << CAL >> appears on the display.
10.
Press the [ + ] key  instead of displaying the old value, the P 97 displays the buffer value of 4.01 (or
11.
9.01), flashing (recognised automatically).
12. Press the [ + ] key to increase the setting.
13. Press the [ - ] key to decrease the setting.
14a. Press the [ CAL ] key to confirm the new setting.
M003-23 - Rev. 03 - 05/2009
Microprocessore µP97
ELECTR.
PT 100
REF.
15 16 17 18
12 13 14
ELECTR.
PT100
REF.
12 13 14
ON
1 2 3 4
REF.
19
15 16
n=01
pH
25