Rockwell Automation 1771-IGD TTL Input Module Installation Instructions - Manual (Page 4)

TTL Input Module 4
Publication 1771ĆIN022B-EN-P - September 2002
For maximum noise immunity, the output of the TTL device should
have a pull-up resistor of 1k ohm (typical). Add an external pull-up
resistor to the output terminals of the device, if necessary. If you add
a pull-up resistor, be sure the TTL device maintains the low state
requirement of -0.2V dc to +0.8V dc with the increased load.
The TTL module requires power from two sources: the I/O chassis
backplane, and a +5V dc Class 2 power supply that you provide for
transmission of TTL signals.
Backplane
The TTL module receives its power through the 1771 I/O chassis
backplane from the chassis power supply. The module requires
130mA from the output of this supply. Add this to the requirements
of all other modules in the I/O chassis to prevent overloading the
chassis backplane and/or backplane power supply.
Customer Supply
You must provide a separate +5(+0.25)V dc Class 2 power supply
for the TTL inputs of the module and for your TTL output devices.
Your module requires 380mA from the output of your supply. Ripple
should not exceed 50mV peak to peak.
The TTL input module is shipped in static-safe packaging to guard
against electrostatic discharge damage. Observe the following
precautions when handling the module.
!
ATTENTION
Preventing Electrostatic Discharge
This equipment is sensitive to electrostatic
discharge, which can cause internal damage and
affect normal operation. Follow these guidelines
when you handle this equipment:
•
Touch a grounded object to discharge potential
static.
•
Wear an approved grounding wriststrap.
•
Do not touch connectors or pins on component
boards.
•
Do not touch circuit components inside the
equipment.
•
If available, use a static–safe workstation.
•
When not in use, keep modules in appropriate
static–safe packaging.
Calculate Power
Requirements
Initial Handling