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Rockwell Automation Publication 1715-UM001J-EN-P - December 2020
Chapter 9 Redundant I/O System Diagnostics
Table 51 - 1715-OB8DE Module Diagnostic Features
Feature
Description
Redundancy level
Simplex or duplex.
Redundancy status
The status of each module of a duplex pair is available in the input tag.
Change of state transport
The connection trigger for the discrete output is change of state. Data is produced when
output data is consumed, or when diagnostic data changes state, or at the Requested
Packet Interval. Unlike the discrete input module, change of state production cannot be
disabled for the discrete output module.
No load detection
A fault is indicated when no load is detected while the output point is in the off state. No
load detection can be disabled to prevent alarms from appearing for unused points.
Short circuit detection
A fault is indicated when a short circuit/over current condition is detected. The fault
indication is reset when the following occurs.
1. Point is commanded off.
2. A short reset service is sent to the module.
3. A reset is done through a bit in the output tag.
Diagnostic latch
When latching is enabled, diagnostic alarms are latched until they are reset. This aids in
detecting intermittent issues. For output modules, latch reset can occur either through
messaging or through a member of the output tag.
Fault mode
When a connection from a controller exists, and the connection is interrupted, the module
outputs take on a user-selected state. This Fault mode is either Off, On or Hold Last State.
Program mode
When a connection from a controller exists, and the controller is not in Run mode, the
module outputs take on a user-selected state. This Program (a.k.a. ‘Idle’) mode is either
Off, On or Hold Last State.
Program to fault enable
When enabled, the outputs assume the fault value when a communication fault occurs
while in Program mode.
ReadBack
The state of each output point is reflected in the input tag.
Table 52 - 1715-IF16 Module Diagnostic Features
Feature
Description
Redundancy level
Simplex or duplex.
Redundancy status
The status of each module is available in the input tag.
Input range
Fixed as 0…20 mA.
Wiring
Single-ended only.
Data format
Read-only.
Scaling
Support choice of signal and engineering range.
Underrange overrange
Diagnostic alarms are provided when the signal goes above or below what the module can
detect. (Zero or less is considered underrange.)
Rolling timestamp
1 ms resolution.
Real time sample rate
Fixed RTS.
Table 53 - 1715-OF8I Module Diagnostic Features
Feature
Description
Redundancy level
Simplex or duplex.
Redundancy status
The status of each module is available in the input tag.
Input range
Fixed as 0…20 mA.
Scaling
Support choice of signal and engineering range.
ReadBack
The state of each output point is reflected in the input tag.
Hold for initialization and enable
Hold for initialization causes outputs to hold present state until the value commanded by
the controller matches the value at the output screw terminal within 0.1% of full scale,
providing a bumpless transfer. A bit in the configuration tag selects whether Hold For
Initialization is used. A bit in the input tag indicates when a channel is holding.
Fault mode/Fault value
When a connection from a controller exists, and the connection is interrupted, the
module outputs take on a user-selected state. This Fault mode is either a user-defined
value or Hold Last State.
Program module/Program value
When a connection from a controller exists, and the controller is not in Run mode, the
module outputs take on a user-selected state. This Program (a.k.a. ‘Idle’) mode is either a
user-defined value or Hold Last State.