AMI CACE
Product Description
A-96.250.871 / 120417
9
Alarm Relay
One potential free contact. Alternatively:
Open during normal operation, closed on error and loss of
power.
Closed during normal operation, open on error and loss of
power.
Summary alarm indication for programmable alarm values and in-
strument faults.
Input
One input for potential-free contact to freeze the measuring value
or to interrupt control in automated installations (
hold
function or
re-
mote-off).
Communica-
tion interface
(optional)
USB Interface for logger download
Third signal output (can be used in parallel to the USB interface)
RS485 with Fieldbus protocol Modbus or Profibus DP
HART interface
Safety
Features
No data loss after power failure. All data is saved in non-volatile
memory.
Over voltage protection of in- and outputs.
Galvanic separation of measuring inputs and signal outputs.
Measuring
principle
When a voltage is set between two electrodes in an electrolyte
solution, the result is an electric field which exerts force on the
charged ions: the positively charged cations move towards the neg-
ative electrode (cathode) and the negatively charged anions to-
wards the positive electrode (anode). The ions, by way of capture
or release of electrons at the electrodes, are discharged and so a
current
I
flows through this cycle and the Ohm’s law
V = I×R
ap-
plies. From the total resistance
R
of the current loop, only the resis-
tance of the electrolyte solution, respectively its conductivity
1
/
R
, is
of interest.
The cell constant of the sensor is determined by the manufacturer
and is printed on the sensor label. If the cell constant has been pro-
grammed in the transmitter, the instrument measures correctly. No
calibration needs to be done, the sensor is factory calibrated. Mea-
suring unit is
S/cm or
S/m.
Specific
Conductivity
Conductivity from all ions in the sample, mainly the alkalization
agent. The contribution of impurities is masked by the alkalization
agent.
Cation Con-
ductivity (Acid
Conductivity)
The alkalization agent is removed by the cation exchange resin in
the EDI module. All cationic ions are exchanged with H+, all anionic
impurities (ions with negative charge) pass through the module un-
changed and are measured by the second conductivity sensor.
Summary of Contents for AMI CACE
Page 1: ...AMI CACE Version 6 20 and higher A 96 250 871 120417 Operator s Manual...
Page 79: ...AMI CACE Index A 96 250 871 120417 77 Terminals 20 22 23 26 U USB Interface 27 W Wire 18...
Page 80: ...78 A 96 250 871 120417 AMI CACE Notes 12 Notes...
