Hazardous area output wiring using galvanic isolators (TPS and Discrete output options)
Figure 4-5:
mA1+
HART
RS-485
PWR
TPS/DO
SIG
Hazardous Area
Non-Hazardous Area
MTL7761AC
MTL5532
RS-485 A
RS-485 B
5
3
4
1
2
1
11
12
13
14
4
1 kΩ
MTL5541
2
1
14
13
12
11
A
24 VDC
24 VDC
1 kΩ
250 Ω
B
A
B
MTL5523
2
1
14
13
12
11
24 VDC
LINK
A. HART/Field Communicator
B. Signal device
CAUTION!
•
In an electrically noisy environment, screen the cable in a safe area.
•
To meet the EC Directive for Electromagnetic Compatibility (EMC), use a suitable instrumentation cable to connect
the meter. The instrumentation cable should have individual screens, foil or braid over each twisted pair, and an
overall screen to cover all cores. Where permissible, connect the overall screen to earth at both ends (360° bonded at
both ends). Connect the inner individual screens at only the controller end.
•
For safety, do not terminate the inner individual screens to earth in a hazardous area.
•
Use metal cable glands where the cables enter the meter amplifier box. Fit unused cable ports with metal blanking
plugs.
Wiring
Installation Manual
33
