Yokogawa EXAxt PH450 4-Wire Analyzer for pH and ORP - Manual (Page 21)

13
IM 12B07C05-01E
3
INSTALLATION
AND
WIRING
3-7. Sensor wiring
Refer to figure 3-10, which includes drawings
that outline sensor wiring.
The EXAxt 450 can be used with a wide range
of commercially available sensor types, both
from Yokogawa and other manufacturers. The
sensor systems from Yokogawa fall into two
categories; the ones that use a fixed cable and
the ones with separate cables.
To connect sensors with fixed cables, simply
match the terminal numbers in the instrument with
the identification numbers on the cable ends.
The separate sensors and cables are not num-
bered, but instead use a color-coding system.
The electrodes have a colored band incorpo-
rated in the label on the connection cap:
• Red for measuring electrodes (both pH
and ORP)
• Yellow for reference electrodes
• Blue for combined sensors with both
measuring and reference elements
in the same body
• Green for temperature sensors
The recommended procedure is to color-code
each end of the cables to match the sensors
with the color strips provided with each cable.
This provides a quick way to identify the ends
of the cables belonging to a particular sensor
when they are installed.
3-7-1. Connection cable
The coaxial cable has two connections.
• Red to measuring element
• Blue to screen (shield)
The triaxial cable has three connections, (it has
an extra white wire termination) these wires are
connected:
• Red to measuring element
• Blue to reference
• White to screen (shield)
To connect the other sensor systems, follow the
general pattern of the terminal connections as
listed below:
Terminal Single Measurement (pH or Redox) Combined measurement (pH and Redox)
pH ORP pH and ORP pH and rH
11 Temperature 1 – Temperature 1 Temperature 1
12 Temperature 2 – Temperature 2 Temperature 2
13 Reference Reference Reference Reference
14 Liquid Earth Liquid Earth ORP ORP
15 pH ORP pH pH
16 Shield of no. 15 Shield of no. 15 Shield of no. 15 Shield of no. 15
17 Shield of no. 13 Shield of no. 13 Shield of no. 13 Shield of no. 13
Note!
• Secondary value is always temperature. For combined pH and Redox measurement, pH is the
primary value and Redox the tertiary value.
• For ORP measurement, temperature is not required for automatic temperature compensation
core
shield
red
blue
Coaxial
red
blue
white
Triaxial
core
shield
red
blue
Coaxial
red
blue
white
Triaxial