TTL Input Module
Cat. No. 1771IGD
Installation Instructions
2
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 se5(+0.25)V dc 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 a static-shielded bag to guard against
electrostatic discharge damage. Observe the following precautions when
handling the module.
Electrostatic Discharge Damage
ATTENTION: Under some conditions, electrostatic discharge
can degrade performance or damage the module. Observe the
following precautions to guard against electrostatic damage.
Wear an approved wrist strap grounding device, or touch a grounded
object to discharge yourself before handling the module.
Do not touch the backplane connector or connector pins.
If you configure or replace internal components, do not touch other
circuit components inside the module. If available, use a static-free
work station.
When not in use, keep the module in its static-shielded bag.
In this section, we tell you how to set the logic level jumper, key your I/O
chassis, install your module and make your wiring connections.
Selecting the Logic Level
Your module is preset to the positive-logic level. Use the following table to
choose between the two logic levels:
If you choose:
Then:
Jumper Position
HIGH = TRUE logic (positive) 2.0 to 5.25V dc corresponds to logic ``1" (on) Toward rear of module
LOW = TRUE logic (negative) -0.2 to 0.8V dc corresponds to logic ``1" (on) Toward front of module
Note: Selecting positive logic automatically enables the HIGH (positive logic) indicator.
Initial Handling
Installing Your Module
