Rockwell Automation 1715-OF8I Redundant I/O System User Manual - Manual (Page 247)

Rockwell Automation Publication 1715-UM001C-EN-P - March 2014 247
Redundant I/O System Diagnostics Chapter 8
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.
Ramp to run Enables ramping of the output value during Run mode between the current output level and a
newly requested output. Ramping defines the maximum rate the output is allowed to transition
at based upon the configured rate by the Maximum Ramp Rate.
Ramp to program Enables ramping to the output value to a user-defined program value. Ramping defines the
maximum rate that the output is allowed to transition based on the configured Maximum Ramp
Rate.
Ramp to fault Enables ramping of the output value to a user-defined fault value. Ramping defines the
maximum rate that the output is allowed to transition at based on the configured Maximum
Ramp Rate.
Maximum Ramp Rate A limit on the rate of change of the output, in engineering units (per scaling) per second. The
Maximum Ramp Rage applies when any of the Ramp to Run, Ramp to Program, or Ramp to Fault
features are enabled.
Ramp rate alarm A diagnostic that is triggered when the rate of change of the output is limited by the Maximum
Ramp Rate.
Ramp alarm latch When latching is enabled, the Ramp Rate Alarm is latched unit it is explicitly reset.
Ramp alarm unlatch When a Ramp Rate Alarm is latched, a bit in the output image can be used to unlatch the alarm.
The unlatch is triggered on a rising edge. If the change in the channel value is still limited by the
Maximum Ramp Rate when the latch is attempted, the alarm remains. (A direct-to-module
message can also be used to unlatch an alarm.)
Clamp limits/Clamp limit alarms Clamping limits the output from the analog module to remain within a range configured by the
controller, even when the controller commands an output outside that range. When a command
value exceeds a clamp limit (either above the High clamp or below the Low clamp), the output is
commanded to the clamp value and an alarm is indicated in the input tag.
Clamp alarm latch When latching is enabled, Clamp Limit Alarms are latched until they are reset. This aids in
detecting intermittent issues.
Clamp alarm unlatch When a clamp alarm is latched, a bit in the output image can be used to unlatch the alarm. The
unlatch is triggered on a rising edge. If the point is till clamped when the unlatch is attempted,
the clamp and alarm remains. (A direct-to-module message can also be used to unlatch an
alarm.)
Not a number A bit in the input tag indicates when the controller has commanded an output value that is not a
number.
Table 53 - 1715-OF8I Module Diagnostic Features
Feature Description
TIP For additional information on 1715-IB16D module diagnostics and
information about how to set threshold values for digital inputs, see
Appendix
C .