Endress+Hauser PROMAG 33, Operating Manual

Page: 96 / 126

7.5 Replacing the transmitter electronics
Warning!
•
Danger from electric shock! Switch off the
power supply before opening the transmitter
housing.
•
When using Ex instruments, they must first cool
down for at least 10 minutes before opening.
•
The local power supply voltage and frequency
must be the same as the technical specifica-
tions of the power supply boards.
•
Ensure that the new electronics board is
the same as the old one before replacing
it (power supply, version of amplifier and
software).
1. Loosen the Allen screws of the safety grip
(3-mm Allen key).
2. Unscrew the cover of the electronics area
of the transmitter housing.
3. Remove the local display as follows:
a.
Loosen the mounting screws of the display
module.
b. Unplug the ribbon cable of the display
from the communications board.
4. Unplug the 2-pole plug of the power supply
cable (by pressing down the catch) from the
power supply board.
5. Remove the electrode signal cable from the
amplifier board:
a. Remove the cable board.
b. Remove the blue DAT module.
c. Loosen the EPD cable from the screw terminals.
6. Loosen the two Phillips screws of the board
support plate. Carefully remove the support
plate approx. 4...5 cm out of the transmitter
housing.
7. Remove the coil current cable plug from
the power supply board.
8. Remove the ribbon cable plug (connection
cable to the terminal area) from the
communications board.
9. The entire transmitter electronics, together
with the board support plate, can now be
completely removed from the housing.
10. Replace the old transmitter electronics
with new transmitter electronics.
11. Reassemble in reverse sequence.
Replacing the DAT module (see 5b):
•
Procedure for replacing the transmitter
electronics
→
plug the old DAT onto the
new amplifier board.
•
Procedure for replacing a defective DAT
→
plug the new DAT onto the old amplifier
board.
DAT = Replaceable data module in which
the basic data of the sensor are stored
(see page 113).
1
2
3a
3b
4
5a
5b
5c
6
8
9
7
Empty Pipe Detection
Terminal for cable screening
(red cable)
Terminal for signal cable
(yellow cable, EPD electrode)
ba
009y
3
6
A
C
B
Fig. 44
Replacing the transmitter
electronics:
A Power supply board
B Amplifier board
C Communications board
Warning!
7 Trouble-shooting, Maintenance and Repairs Promag 33
96 Hauser