General Notes - Danfoss GDA Installation Manual

Heavy Duty GDU (Atex, IEC approved)
The Heavy Duty GDU is designed for the connection of 1 sensor via local
bus.
The GDU provides the power supply of the sensor and makes the
measured data available for digital communication. Communication
with the Controller Unit takes place via the RS 485 fieldbus interface
with Controller Unit protocol. Other communication protocols for direct
connection to superordinate BMS are available as well as Analog Output
4-20 mA.
The sensor is connected to the local bus via a plug connection enabling
simple sensor exchange instead of an on-site calibration. The internal
X-Change routine recognizes the exchanging process and the exchanged
sensor and starts the measurement mode automatically.
The internal X-change routine examines the sensor for actual type of
gas and actual measuring range. If data does not match the existing
configuration, the build in status LED indicates an error. If everything is OK
the LED will light up green.
For convenient commissioning, the GDU is pre-configured and
parameterized with factory-set defaults.
As an alternative, the on-site calibration via the Controller Unit Service Tool
can be performed with the integrated, userfriendly calibration routine.
Installation Work
Assembly work must only be carried out under gas-free
conditions. The housing must neither be drilled nor be
drilled through.
The orientation of the GDU should always be horizontal,
with the sensor head pointing downwards.
The mounting is done without opening the housing by
using the two holes (D = 8 mm) of the fastening strap with
suitable screws.
The Heavy duty GDU must only be opened under gas-free
and voltage-free conditions.
The enclosed cable gland has to be checked for
admissibility for the requested requirements before
installation in position "Entry 3". If the Heavy duty
GDU is supplied without cable gland, a special cable
gland approved for Ex protection class EX d and for the
requirements of the application has to be mounted there.
When inserting the cables you have to strictly follow the
instructions enclosed to the cable glands.
No insulating sealing material must be poured into the NPT
¾ "threads of the cable gland and blanking plugs because
the potential equalization between housing and cable
gland / blind plugs is via the thread.
The cable gland must be tightened firmly with a suitable
tool. Only when doing so you can ensure the required
tightness.
After completion of work, the GDU must be closed again.
The cover has to be completely screwed in and secured
with the locking screw against inadvertent loosening.
© Danfoss | DCS (MWA) | 2018.04
ENGLISH

General Notes

• The terminals of the Heavy duty GDU are located behind the display.
• Only a professional should perform the wiring and the connection of
the electrical installation according to the wiring diagram in compliance
with the relevant regulations and only when de-energized!
• When connecting cables and conductors, please observe minimum
length of 3 m according to EN 60079-14.
• Connect the housing to the equipotential bonding via the external
ground terminal.
• All terminals are Ex e type with spring contact and push actuation. The
permissible conductor cross section is 0.2 to 2.5 mm2 for single wires
and multi-wire cables.
• Use cables with a braided shield for compliance with the interference
immunity. The shield must be connected to the inside connection of the
housing with a maximum length of about 35 mm.
• For the recommended cable types, cross sections and lengths please
refer to the table below.
• To comply with the requirements of servicing or operating the device
without opening it (EN 60079-29- 1 4.2.5) it is possible to calibrate or
operate the device remotely via the central bus. For this it is necessary
to lead the central bus out to the safe area via a cable.
Cross-section
Operating voltage with
4-20 mA signal
Operating voltage with
central bus2
Operating voltage with
4-20 mA signal
Operating voltage with
central bus2
1 The max. cable lengths and our recommendation don't consider any local conditions, like fire
protection, national regulations etc.
2 For the central bus we recommend using the cable JE-LiYCY 2x2x0.8 BD or 4 x2x0.8 BD.
Max. length for 24 V DC1
(mm2) (m)
With P, freon sensor heads
0.5 250
1.0 500
0.5 300
1.0 700
With SC, EC sensor heads
0.5 400
1.0 800
0.5 600
1.0 900
DKRCI.PI.S00.F2.02 | 520H12487 | 7