Rockwell Automation 1769-IF4XOF2 Compact 8-Bit Low Resolution Analog I/O Combination Module - Manual (Page 55)

Publication 1769-UM008A-EN-P - November 2001
1769-IF4XOF2 Module Data, Status, and Configuration Channels 4-11
that the analog output remains at the last converted value prior to the
condition that caused the system to enter the fault mode.
•
Hold Last State (0) – When reset, this bit directs the module to
hold the analog output at the last converted value when the
module transitions to Fault Mode. This is the default condition.
•
User-Defined Safe State (1) – When this bit is set and the module
transitions to Fault mode, the module converts the user-specified
integer value from the Channel x Fault Value Word (2 or 4) to
the appropriate analog output for the configured range as wired.
If the default value, 0000, is entered, the output converts to the
minimum value for the range selected.
Program to Fault Enable Selection (PFE0 and PFE1)
The Program to Fault Enable bit determines which data value,
Program (PFEx = 0) or Fault (PFEx = 1), is applied to the output if the
module undergoes a fault condition while in the Program Mode,
resulting in a change to Fault Mode. Word 0 Bit 0 applies to channel 0,
while Word 1 Bit 0 applies to channel 1.
•
Program Value (Channel 0 and 1) – Words 3 and 5 allow you to
enter the integer values that output Channel 0 (Word 3) and
output Channel 1 (Word 5) should assume when the system
transitions to the Program mode. The value must be in
increments of 128 (0, 128, 256, etc.) for proper operation. If the
value entered is outside the acceptable increment or range, the
module generates a configuration error for that channel. The
module default value is zero.
IMPORTANT
Hold last state is the default condition for the module
during a control system run-to-fault mode change.
TIP
MicroLogix 1500 does not support the analog output
module’s default hold last state function and resets
analog outputs to zero when the system enters the
fault mode.
TIP
Not all controllers support this function. Refer to
your controller’s user manual for details.