3.6.2
Wire to a signal converter/flow computer in an
intrinsically safe area
Wiring to a signal converter/flow computer in an intrinsically safe area
Figure 3-14:
mA1+
HART
RS-485
PWR
TPS
A
A
B
Hazardous Area
Non-Hazardous Area
MTL7761AC
RS-485 A
RS-485 B
3
4
1
2
24 VDC
M
3
4
1
2
M
3
4
1
2
M
3
4
1
2
A
B
A.
Active HART host
B.
Active signal converter/flow computer
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
40
Micro Motion Compact Density Meter
