User Manual Owner's manual

Publication 1797-6.5.2 - February 2001

Applying FLEX Ex Thermocouple/RTD/mV Input Modules 6-9

Each power supply output in the FLEX Ex system is rated for 8.5W.

Modules can be attached to the output until their combined power

equals that number. Do not exceed the power supply maximum of

8.5W.

Assign the next module to another output as before. When all four

power supply outputs are utilized, add another power supply to the

system, see the figure below.

Power Supply Considerations

When applying power, consider the certain characteristics of the wire

connecting the power supply output to a module’s power input. The

wire cannot exhibit more than:

• 0.1Ω of resistance (+V and -V combined)

• 800nF of capacitance

• 10mF of inductance

Typically, these restrictions will yield wiring lengths of not more than

3.5m or 5.8m (1.5mm

and 2.5mm

wire respectively) without the use

of special wiring or wiring methods.

IS Pwr

Safe Area

Hazardous Area

1797 power supply

ACNR Spare IE8 OE8 IRT8 Spare Spare IJ2 IJ2

ACNR OB4D OB4D IBN16 IBN16 IBN16 IE8 IRT8 OE8

RPA RPFM RPFM

IS 1797 I/O

IS 1797 Fiber Hub

IS Pwr

EEx d

EEx ib

EEx d

EEx ib

EEx d

EEx ib

41306

Unsafe

Power

Entrance

Spare