Rockwell Automation 1797-PS1N FLEX Ex 85-250V AC In/Quad-Ex DC Out Power Supply - Manual (Page 4)

4 FLEX Ex 85…250V ac In/Quad-Ex dc Out Power Supply
Publication 1797-5.34 - September 2011
Features include the following:
• 85…250V ac supply source
• Four channels, 8.5 W output each channel
• Outputs are IS galvanically isolated from the source
• All channels are independently IS limited
Understand System Planning
Part of system planning is determining what modules are needed for the
application, how many power supplies are needed, how to best partition the
system, and where to locate the system cabinets.
A key task in the development cycle is determining the number of power
supply outputs (thus power supplies) you will need. In the following example,
you will need eleven power outputs if you are using the fiber hub, which
requires 8.5 W as shown below.
Each power supply has four independent IS power outputs capable of 8.5 W
each. In the above example, we required 11 IS power outputs so 3 power
supplies were sufficient.
The total number of power supplies needed depends on the modules used
and the total system configuration. The following illustration shows how this
example may be configured.
Modules Requires Modules Requires
Fiber hub 8.5 W Two thermocouple inputs 1.6 W each
Two ControlNet adapters 8.5 W each Two digital outputs 7.5 W each
Two analog inputs 7.5 W each Three NAMUR digital inputs 2.8 W each
Two analog outputs 6.3 W each Two counter inputs 4.25 W each