70
TN4FCXA2
j
-EDF-
E
An optional surge protector can be used to protect the transmitter against the accidental surges
that may occur on the power supply. This surge protector is mounted in the terminal block of
the transmitter.
In this case, a label
“With Arrester”
is pasted on the terminal block.
Installation
If power surges are likely to appear on the 4/20 mA loop, for example because of the lightning,
it is advisable to also install a surge protector at the end of the line, at the side where it is used
(control room), to protect the instruments that also receive the signal from the transmitter.
Transmitter
Surge protector at the
end of the line
Use of the
signal from the
transmitter
Outer earthing
terminal
Earthing
The earth terminal of the surge suppressor is connected to that of the transmitter, on the inside.
It is therefore only necessary to link that the external terminal of the transmitter to the earth.
The internal terminal for earthing is only used if a transmitter with intrinsic safety or an explosion-
proof one is used.
+
-
E
1
5
2
6
E
1
+
1
-
SURGE PROTECTOR
A1
The total resistance of the earthing circuit will be less than 100
Ω.
For earthing, do not use an earthing cable intended for a protection against
lightning.
In the case of a device with the option of a surge protector, the maximum
supply voltage is 32 Vdc.
Inner earthing
terminal
CK
+
CK
-
+
-
Outer earthing
terminal
INDICATION
