Specifications

105 Publication 1794-SG002D-EN-P - May 2012
Section 2.5
Select a FLEX Ex I/O Power Supply
Step 4 – Select:
if power consumption exceeds the maximum for a single power supply,
install additional power supplies
The power supply is an essential component in the operation of an intrinsically
safe system. It must isolate the unsafe incoming power from the control system
and limit the available energy to IS-safe levels.
FLEX Ex I/O power supplies provide power for the FLEX Ex ControlNet
network, communication adapter, I/O modules, fiber hub, and IS field devices.
No other power sources are needed to operate any components attached to the
FLEX Ex system in the hazardous area. Power for valves, actuators, or
transmitters come from the FLEX Ex modules.
FLEX Ex I/O power supply modules must be used to supply power to
FLEX Ex I/O modules. Other power supplies are not allowed in order to meet
the certification of the system. Power for valves, actuators, and transmitters come
from the FLEX Ex modules.
There are two types of enclosures: (N-Type) explosion-proof with 1 inch conduit
pipe thread input/output terminations that are certified in North America and
(E-Type) flame-proof with increased safety input/output terminations that are
certified to European standards. Each type is available in 24V DC or
85...253VAC for supply sources.
The 24V DC power supply includes dual power feeds for sour input redundancy
whereas the AC power supplies support daisy chaining.
Common features include:
• four channels, 8.5 W output each channel
• outputs are IS galvanically isolated from the source
• all channels are independently IS limited
General Specification Comparison
Catalog Description Input Voltage, max Output Power (W) Dimensions
(HxWxD), approx
Weight
approx
1797-PS1N FLEX Ex 85…250V AC Power Supply 250V AC 34 W
(1)
174 x 174 x 140 mm
(6.9 x 6.9 x 5.51 in.)
6 kg
(13.2 lbs)
1797-PS1E FLEX Ex 24V DC Power Supply 253V AC 260 x 174 x 140 mm
(10.2 x 6.9 x 5.51 in.)
6.9 kg
(15.2 lbs)
1797-PS2N2 FLEX Ex conduit pipe North
American-certified Power Supply
32V DC max 174 x 174 x 140 mm
(6.9 x 6.9 x 5.51 in.)
6.1 kg
(13.4 lbs)
1797-PS2E2 FLEX Ex flame-proof European-certified
Power Supply
260 x 174 x 140 mm
(10.2 x 6.9 x 5.51in.)
7 kg
(15.4 lbs)
(1) 8.5 W at each of 4 outputs.