Rockwell Automation VersaView 1200P Integrated Display Computers for Hazardous Locations - Manual (Page 16)

16 VersaView 1200P Integrated Display Computers for Hazardous Locations
Publication 6183H-IN001E-EN-P - July 2007
Application Information
The circuit parameters of associated field-wired apparatus for use in hazardous
locations shall be coordinated with the host product such that their combination
remains nonincendive. The VersaView 1200P computer, and the PS2 and USB
peripheral devices shall be treated in this manner.
The circuit parameters of the VersaView 1200P computer’s USB and PS2 ports are
given in the VersaView 1200P USB and PS2 Port Circuit Parameters table. The
VersaView 1200P computer provides two separately powered USB ports and two
parallel powered PS2 ports.
The USB and PS2 peripheral devices and their associated cabling shall have circuit
parameters with the limits given in the Required Circuit Parameters for USB and PS2
Peripheral Devices table for them to remain nonincendive when used with the
VersaView 1200P computer’s USB and PS2 ports.
For the comparison of C
o (PS2)
and C
i (PS2)
, use the sum of the capacitance of all
connected PS2 peripheral devices and their associated cables C
cables
.
For the comparison of C
o (USB)
and C
i (USB)
, use the capacitance of each individual
connected USB peripheral device and its associated cable C
cable
.
For the comparison of L
o (USB)
with L
i (USB)
and L
o (PS2)
with L
i (PS2)
, use the
inductance of each individual peripheral device and its associated cable for L
i
.
If cable capacitance and inductance are not known, the following values may be
used:
C
cable
= 60 pF/ft (197 pF/m)
L
cable
= 0.20 µH/ft (0.66 µH/ft)