Industrial Computers for Hazardous Locations
17
Rockwell Automation Publication 6181X-IN001C-EN-P - April 2011
Control Drawing - Class I Division 2 and Zone 2 Required Circuit
Parameters for USB Peripheral Devices
The following control drawing is provided in accordance with the National Electrical Code,
Article 500 (Class I, Zone 2, Group IIB and Class I, Division 2, Groups A, B, C and D).
Parameter
Value
Parameter Definition
V
oc (USB)
5.25V DC
Open circuit voltage of each host USB port.
The maximum applied voltage rating, V
max (peripheral)
, of each peripheral
device shall be greater than or equal to V
oc
(USB)
.
V
max (peripheral)
≥
V
OC (USB), as appropriate
I
sc (USB)
950 mA
Maximum output current of each host USB port.
The maximum current, I
max (peripheral)
, to which each USB peripheral
device can be subjected shall be greater than or equal to I
sc
(USB) .
I
max
(peripheral)
≥
I
sc
(USB)
C
a (USB)
20 µF
This value is the maximum total capacitance that can be connected to
each USB port. The total capacitance of each USB peripheral and its
cable must not exceed the indicated value.
The maximum total capacitance, C
i (peripheral),
and cable capacitance of
each separate USB peripheral device shall be less than or equal to C
a
(USB)
.
C
i ( peripheral)
+ C
cable
≤
C
a (USB)
L
a (USB)
3.11 µH
This value is the maximum total inductance that can be connected to
each USB port. The total inductance of each peripheral device and its
cable must not exceed the indicated value.
The maximum total inductance, L
i (peripheral),
and cable inductance of
each separate USB peripheral device shall be less than or equal to
L
a (USB).
L
i (peripheral)
+ L
cable
≤
L
a (USB)
USB Port
USB Peripheral Device
USB Port
USB Peripheral Device
USB Port
USB Peripheral Device
USB Port
USB Peripheral Device
6181X Host Product
Associated Nonincendive
Field Wiring Apparatus
Nonincendive Field
Wiring Apparatus
