Allen-Bradley 1771-OG User manual

TTL Output Module
Cat. No. 1771OG
Installation Instructions
This document provides information on:
important pre-installation considerations
power supply requirements
initial handling procedures
installing the module
using the indicators for troubleshooting
module specifications
You can use any TTL device that meets the input logic level specification
of -0.2V dc to +0.8V dc (low), and 2.0V dc to 5.25V dc (high).
The TTL module requires power from two sources: the I/O chassis
backplane, and a +5V dc 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 168mA
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 power supply for TTL outputs
from the module and for your TTL input devices. Your module requires
250mA from the output of your supply. Ripple should not exceed 50mV
peak to peak.
To The Installer
Preinstallation
Considerations
Power Requirements

TTL Output Module
Cat. No. 1771OG
Installation Instructions
2
The TTL output 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.
This section explains how to:
select the logic level
key the I/O chassis
install the module
make the wiring connections
Selecting the Logic Level
You can select one of two logic conditions:
If you choose: Then: Set Switch SW:
HIGH = TRUE logic 2.0 to 5.25V dc corresponds to logic ``1" (on) SW1 - on, SW2* - on
LOW = TRUE logic -0.2 to 0.8V dc corresponds to logic ``1" (on) SW1 - off, SW2* - on
* SW2 setting is optional for HIGH-TRUE indicator.
Select high-true or low-true using the switch assembly inside the module.
Initial Handling
Installing Your Module

TTL Output Module
Cat. No. 1771OG
Installation Instructions
3
1. Remove the side cover from the module by removing the screw at
each of the four corners.
2. Set the switches as needed for your application.
12
O
N
O
F
F
When OFF, LOW = TRUE
logic selected.
When OFF, HIGH = TRUE
indicator does not illuminate.
When ON, HIGH = TRUE
indicator illuminates
continuously.
When ON, HIGH = TRUE
logic selected.
TTL Output Module
(cover removed)
10446-I
TTL Logic Level Selection Switch Assembly
3. Reinstall the cover and secure with the four screws.
Keying Your I/O Chassis
Use the plastic keying bands, shipped with each I/O chassis, to key the I/O
slots to accept only this type of module.
The module circuit board is slotted in two places on the rear edge. The
position of the keying bands on the backplane connector must correspond
to these slots to allow insertion of the module. You can key any connector
in an I/O chassis to receive this module except for the left-most connector
reserved for adapter or processor modules. Place the keying bands between
the following numbers labeled on the upper backplane connector:
Between 6 and 8
Between 10 and 12
You can change the position of these keys if system redesign and rewiring
makes insertion of a different module necessary.

TTL Output Module
Cat. No. 1771OG
Installation Instructions
4
Installing the Output Module
To install the TTL output module in your 1771 I/O chassis, follow the steps
listed below:
ATTENTION: You must first turn off power to the 1771 I/O
chassis backplane and field wiring arm before removing or
installing an I/O module.
Failure to turn off power to the backplane or field wiring arm
could cause personal injury, module damage, or degradation
of performance.
Failure to turn off power to the backplane could cause
personal injury or equipment damage due to possible
unexpected operation.
1. Turn off power to the I/O chassis.
2. Place the module in the plastic tracks on the top and bottom of the
slot that guides the module into position.
3. Do not force the module into its backplane connector. Apply firm,
even pressure on the module to seat it properly.
4. Secure the module’s position by doing the following:
With a Series A chassis, snap the chassis latch over the top of the module
With a Series B chassis, pull down the locking bar
5. Connect the field wiring arm to the output module.
Connecting Wiring to the Output Module
Connect wiring to the input module using the field wiring arm (cat. no.
1771-WC) shipped with the module (shown in the following figure). Make
your connections as follows:
1. Attach the field wiring arm to the pivot bar on the bottom of the I/O chassis.
2. Pivot the field wiring arm upward and push it into the module until
the field wiring arm clicks into position. The field wiring arm is
designed to let you install and remove the module without
disconnecting the wires.
ATTENTION: Do not apply ac or reverse dc voltage to module
terminals. Circuitry at the input of module may be damaged.

TTL Output Module
Cat. No. 1771OG
Installation Instructions
5
3. Separate the shielded cables from wiring that radiates electrical noise.
Refer to category 2, low power dc I/O lines, in publication 1770-4.1,
‘‘Programmable Controller Wiring and Grounding Guidelines”.
4. Prepare the cable for grounding by doing the following:
Remove a length of cable
jacket from the Belden 8761
cable.
Pull the foil shield and bare
drain wire from the insulated
wires.
Bare drain
wire
Insulated
wires
Foil
shield
Twist the foil shield and drain
wire together to form a single
strand.
Attach a ground lug.
20104
Belden 8761 Cable
5. Ground the single strand (at the ground lug end) to the grounding
stud on the I/O chassis or by using single-point grounding.
19480
When you connect grounding conductors to the I/O chassis
grounding stud, place a star washer under the first lug, then
place a nut with captive lock washer on top of each ground lug.
Grounding Stud
1Use
the cup washer if crimpon lugs are not used.
Chassis Ground Singlepoint Grounding
Ground Lug
Nut
Ground Lug1
Star
Washer
I/O Chassis Side Plate
Nut and Captive
Washer
Externaltooth Washers
#10 Threadforming screw
19923

TTL Output Module
Cat. No. 1771OG
Installation Instructions
6
6. You must connect both ends of the insulated signal return wire in
each transmission cable as follows:
connect one end to the dc common terminal of your +5V dc power
supply
connect the other end to the dc common terminal of the field
wiring arm
A
O
1
2
3
4
5
6
7
8
dc common
+5V dc
Output 0
Output 1
Output 2
Output 3
Output 4
Output 5
Output 6
Output 7
Customer
Power Supply
+5V dc
+-
1
1Add a pullup resistor (1K ohm typical)
if not internal to the device.
(See applicable codes and laws.)
+
-
The outputs of the 1771OG are opencollector with
internal 1K pullup (up to 5V) resistors.
(Actual wiring runs in this direction.)
1
10447-I
Field Wiring Arm
Cat.. No. 1771WC
Ground cable shield at the chassis
grounding stud or by using single
point grounding
7. Connect TTL output devices using Belden 8761 shielded cable as
shown in the connection diagram. Do not exceed 50 cable feet for any
output device. Connect the insulated wires to their respective
terminals on the field wiring arm.
Driving Inputs with Outputs
Output terminals of the TTL output module (cat. no. 1771-OG) may
directly drive inputs of a TTL input module (cat. no. 1771-IG). Connect
the cable shield between modules at one end only.

TTL Output Module
Cat. No. 1771OG
Installation Instructions
7
The front panel of your module contains nine status indicators (Figure 1).
The red top indicator is labeled ‘‘HIGH = TRUE.” When on, it indicates
you selected high-true logic (SW1 on and SW2 on). When off, it indicates
you selected low-true logic (SW1 off and SW2 on).
Each of the lower eight red indicators light when their corresponding
output terminal delivers TTL voltages in the true state.
Indicators may appear dim during rapid pulsing of output signals.
Figure 1
Status
Indicators
HIGH = TRUE indicator
Output 0
Output 1
Output 2
Output 3
Output 4
Output 5
Output 6
Output 7
Status Indicators
10448-I
Interpreting the Status
Indicators

Specifications
TTL Output Module
Cat. No. 1771OG
Installation Instructions
8
Outputs per Module 8
Module Location 1771 I/O chassis
Output Voltage Range
HIGH = TRUE
LOW = TRUE
ON: 2.0 to 5.25V dc
OFF: -0.2 to +0.8V dc
ON: -0.2 to +0.8V dc
OFF: 2.0 to 5.25V dc
Maximum Output Current Source: 1mA; Sink: 20mA
Customer Supply Voltage 5V dc (+0.25V)
50mV peaktopeak ripple max.
Customer Supply Current per Module 250mA max.
Output Signal Delay Less than 1ms
Power Dissipation 2.2 Watts (max.); 0.8 Watts (min.)
Thermal Dissipation 7.5 BTU/hr (max.); 2.7 BTU/hr (min.)
Backplane Current 168mA max.
Isolation Voltage Tested at 1500V ac (rms) for 1 second
Environmental Conditions
Operational Temperature
Storage Temperature
Relative Humidity
0oto 60oC (32oto 140oF)
-40oto 85oC (-40oto 185oF)
5 to 95% (without condensation)
Conductors Wire Size
Cable
Category
14 gauge stranded maximum
3/64 inch insulation maximum
Shielded, (Belden 8761)
21
Keying Between 6 and 8
Between 10 and 12
Field Wiring Arm Catalog Number 1771WC
Wiring Arm Screw Torque 79 inchpounds
1Refer
to publication 17704.1 ` `Programmable Controller Wiring and Grounding Practices."
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Publication 17712.177 January 1994
Supersedes Publication 17712.131 - May 1989
PN 95510767
Copyright 1994 AllenBradley Company , Inc. Printed in USA