Understanding i/o specifications, Digital inputs and outputs, Digital input power – Rockwell Automation 8720MC High Performance Drives Installation Manual User Manual
Page 45: Digital inputs, Understanding i/o specifications -11, Digital inputs and outputs -11, Digital input power -11, Digital inputs -11

Publication 8720MC-IN001D-EN-P — December 2002
8720MC Connector Data
2-11
Understanding I/O
Specifications
A description of the 8720MC input/output is provided on the
following pages.
Digital Inputs and Outputs
The 8720MC High Performance Drives support 10 digital inputs, 4
relay contact outputs and 6 digital outputs.
These are sinking inputs that require a sourcing device. A 24V power
and common connection is provided for use with the inputs.
Digital Input Power
The isolated +24V dc power available from the 8720MC is limited to
120 mA and is adequate for use with the 10 digital inputs but may be
inadequate when the full set of 6 digital outputs are used. Keep
current requirements below 120 mA (total) when using the 8720MC
isolated +24V dc power for digital I/O. If more than 120 mA is
required, provide an external (+24V dc) power supply.
Digital Inputs
Digital input specifications for SERCOS drives are shown in the table
below. These inputs are optically isolated to 500V from control power.
They have hardware filtering with a time constant and a software
debounce, which requires stable input prior to validation. Values are
shown in the table below. A description of these signals is provided
beginning on page 2-12.
IMPORTANT
To improve registration input EMC performance,
refer to the System Design for Control of Electrical
Noise Reference Manual (GMC-RM001x-EN-P).
Pin
Signal
Capture
Time
Edge/Level
Sensitive
Hardware
Filtering
P5-14
DRIVE ENABLE
5 ms
Level
300 µs
P5-35
HOME SWITCH
5 ms
Level
300 µs