User's Manual

Electrical installation
Installation guide 970 SmartRadar ATi Page 15
Caution
The intrinsically safe options described in this section have been certified as explosion-proof.
Make sure that the certificate of approval is available on site and act in accordance
with the instructions as given in the approval certificate.
Caution
Intrinsically safe wiring shall be separated from all other wiring.
Cable lay-out shall be in accordance with local regulations.
Intrinsically safe connections
The cable for the intrinsically safe option(s) should be fed through the cable entry at the side of the
intrinsically safe (blue) terminals. Blue marked cables are recommended for the I.S. options.
If more than one connection is to be made, an external junction box is required.
Note:
The shield of the intrinsically safe cable shall not be connected inside the SmartRadar ATi
housing. Connect the shield of the cable externally in the cable gland at both ends of the cable.
Device Cable requirement
Spot temperature element : Shielded; R = 12 Ω / line.
max
Average temp. element : Twisted pair and shielded; R = 25 Ω / line.
max
(combined water probe)
Pressure transmitters : Twisted pair and shielded; R = 25 Ω / line (only pressure
max
transmitters with HART protocol).
®
Pressure transmitter P1 is the bottom transmitter (measures liquid
head) and P3 is the top transmitter (measures vapour pressure).
Water bottom probe : Twisted pair and shielded; R = 25 Ω / line
max
(separate from temp. elem.) (only with HART protocol).
®
Tank Side Indicator : Twisted pair and shielded; R = 5 Ω / line, maximum cable length
max
50 m (160 ft).