Yokogawa DO202 2-Wire Dissolved Oxygen Analyzer - Manual (Page 34)

IM 12J05C01-01E
3-2. Wiring of power supply
3-2-1. General precautions
Do not activate the power supply yet. First make
sure that the DC-power supply is according to the
specifications given.
DO NOT USE ALTERNATING CURRENT OR MAINS
POWER SUPPLY! !
The cable leading to the distributor (power supply) or
safety barrier transports power to and output signal
from the transmitter. Use a two conductor shielded
cable with a size of at least 1.25 mm 2 and an outside
diameter of 6 to 12 mm. The cable gland supplied
with the instrument accepts these diameters. The
maximum length of the cable is 2000 metre, or 1500
metres when using the communications. This ensures
the minimum operating voltage for the instrument.
Grounding:
• If the transmitter is mounted on a grounded
surface (e.g. a metal frame fixed in the soil) the
shield of the 2-wire cable may NOT be connected
to ground at the distributor.
• If the transmitter is mounted on a non-conducting
surface (e.g. a brick wall) it is recommended
to ground the shield of the 2-wire cable at the
distributor end.
3-2-2. Connection of the power supply
The terminal strip is accessed as was described in
section 3-2-1. Use the left-hand gland to insert the
supply/output cable to the transmitter. Connect the
supply to the terminals marked +, - and G as is indi-
cated in figures 3-7.
3-2-3. Switching the instrument on
After all connections are made and checked, the
power can be switched on from the distributor.
Observe the correct activation of the instrument at
the display. If for any reason the display does not
indicate a value, consult the trouble shooting section.
3-2-4. Preparation
Refer to figure 3-4. The power/output connections
and the sensor connections should be made. Refer
to figure 3-7. The terminals are of a plug in style for
ease of mounting.
To open the EXA 202 for wiring:
1. Loosen the four frontplate screws and remove
the cover.
2. The terminal strip is now visible.
3. Connect the power supply. Use the gland on the
left for this cable.
4. Connect the sensor input, using the gland on
the right (see fig. 3-5). Switch on the power.
Commission the instrument as required or use
the default settings.
5. Replace the cover and secure frontplate with the
four screws.
6. Connect the grounding terminals to protective
earth.
7. The optional hose connection is used to guide the
cables coming from an immersion fitting through a
protective plastic tubing to the transmitter.
3-2-5. Cables, terminals and glands
The DO202 is equipped with terminals suitable for
the connection of finished cables in the size range:
0.13 to 2.5 mm (26 to 14 AWG). The glands will
form a tight seal on cables with an outside diameter
in the range of 6 to 12 mm (0.24 to 0.47 inches).
3-3. Wiring of sensors
3-3-1. Wiring the standard galvanic sensor
The sensor cable has markers on the individual wires.
These markings refer to the markers on the terminals.
The temperature sensor has two wires with the
markings T1, T2 and/or 11, 12 and must be con-
nected to terminal 11 and 12.
The measuring electrode: the cathode is marked with
IE and/or 13 and must be connected to terminal 13.
The reference electrode: the anode is marked with
RE and/or 15 and must be connected to terminal 15.
The liquid earth (solution ground) is marked with 16
and must be connected to terminal 16.
The overall shield of the cable is marked with 14
and must be connected to terminal 14.
Place the jumper in the GALVANIC position.
WARNING WARNING
3-3 Installation and Wiring
Grounding terminal
Power/Output
cable gland
Sensor
cable gland
Figure 3-5. Glands to be used for cabling
mA
mA
mA