Model MR Installation Manual - MTS Sensors

Electrical Connections
& Wiring
Model MR Operation and Installation Manual
Electrical Connections, Wiring and Safety
Electrical connections and wiring procedures
A typical intrinsically safe connection for the Level Plus Model MR transmitter includes protective safety barriers, a power supply and a
reading or monitoring device. Refer to Agency information for detailed information.
A typical explosion proof connection for the Model MR transmitter includes a power supply and a reading or monitoring device connected
using explosion proof conduit. Refer to Agency information for detailed information.
Notes:
For explosion proof installation, safety barriers are not required and wiring shall be installed in accordance with the National Electric Code ANSI/NFPA 70,
Article 501-30 or the regional equivalent.
Safety recommendations for installation
Be sure to:
1. Always follow applicable local and national electrical codes and observe polarity when making electrical connections.
2. Never make electrical connections to the M-Series transmitter with power turned on.
3. Make sure that no wire strands are loose or sticking out of the terminal block connection which could short and cause a problem.
4. Make sure that no wire strands, including shield, are in contact with the electronic module enclosure.
5. The electronics module enclosure is grounded through internal circuitry and is electronically isolated from the explosion-proof housing.
Refer to the safe operating power chart (see Figure 10), which shows the relationship between loop resistance and operating voltage.
Resistance
(Ohms)
800
750
INSUFFICIENT
700
OPERATING POWER
650
600
550
500
450
400
350
300
250
200
150
EXCESS POWER
100
50
0
10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
Supply Voltage
(Volts DC)
Figure 10. Safe operating power chart
Level Plus ® Liquid-Level Sensors - M-Series Model MR Analog Transmitter
Operation and Installation Manual, Document Number 550720 Revision G, 09/11 EN 14
MTS Sensors