Technical data

May 2007
CA05001001E For more information visit: www.eaton.com
39
PLC, I/O & Communications Products
IT. Connect
Remote I/O Modules (D77A Series)
Features, Functions and
Benefits
Scalable Solutions
Since each application is different, the
I/O offering has been designed to
allow for maximum flexibility to tailor
the I/O needs of our customer. The I/O
product offering includes not only 8
and 16 point modules but also combi-
nation I/O modules. Signal types
include 24V DC I/O, 120V AC I/O, solid-
state outputs, relay outputs, analog
inputs and analog outputs.
All Modules
LED Status – When the LED is illumi-
nated, the proper ON state signal is
received at the input or the output point.
Removable Lockable Terminals – To
facilitate easy removal of the I/O
module, the terminal block has been
designed to be easily removed with
the field wiring installed. A unique
locking mechanism provides for easy
removal of the terminal block and also
positive locking of the terminal to the
I/O module.
Terminal Identification – Each terminal
is marked for ease of wiring and trou-
bleshooting.
Isolation – Each I/O module is optically
isolated between the field I/O and the
network adapter.
Securing Tabs – Each I/O module has a
locking mechanism so that it can be
positively secured to a DIN rail.
Barrier Type Terminals – Each terminal
has a barrier to minimize shorting of
field wiring.
Removal/Insertion – Each I/O module
supports removal and insertion under
power.
Interconnection System – Each I/O
module supports both a backplane
style interconnect and a cable
interconnect system for system
communication.
Points per Common – Each I/O module
supports two I/O points per isolated
common except for the DC output
module which is four points per
isolated common.
Input Modules
Input Filter – Each input module supports
a user definable input debounce. The
time can be set from 1 mS to 250 mS.
Output Modules
Output Safe State – Each output module supports a user definable safe state for
loss of communication. The states are hold last state, ON or OFF (default).
Configurable Power ON State – When the output module initially powers up and
prior to system communication starting, the outputs can be preconfigured to go to
a predefined state which can be ON or OFF (default).
Operation
When the D77A I/O Modules are properly installed and each has a properly config-
ured Group ID, no configuration is needed for standard operation.
Discrete Input Modules
When a signal is present at the input point, the module responds using the follow-
ing procedures:
1. Optical Isolation – Optical isolation protects the I/O circuits and communica-
tion circuits from possible damage due to transients and overvoltage.
2. Debounce Logic/Control – Debounce limits the effects of transients and elec-
trical noise by requiring the input to be true for a certain period of time before
the logic acknowledges a true signal. Once a true signal is achieved, the logic
turns on the LED.
Figure 42. Input Module Operation
Discrete Output Modules
When an output is commanded to change state, the module responds using the
following procedures:
1. Optical Isolation – Optical isolation protects the I/O circuits and communica-
tion circuits from possible damage due to transients and overvoltage. Once an
active signal is sent to the optical isolation, the LED is activated.
2. Output Drivers – The driver turns on the output point.
Figure 43. Output Module Operation
Communication
Adapter
Optical
Isolation
Debounce
Logic/Control
Input
LED
Indication
Communication
Adapter
Optical
Isolation
Output
Drivers
Output
LED
Indication