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170ANR1209x Discrete Inputs Oscillate On/Off Under Certain Conditions

Release Notice

The purpose of this Resolution is to inform users of 170ANR12090 and 170ANR12091 Momentum I/O Bases of a problem with the discrete input data oscillating on and off, although no input signals are present.


Goals and Symptoms

The discrete input bits (lower byte of input word 2) will continuously oscillate on/off when at least one of the inputs is turned on from the field side. This occurs if the parameters for the analog outputs are set to either of the following two configurations:

  1. When ‘User Defined Value’ is selected for Channel 3 and the value is set greater than 255 decimal or 100 hex. (4x I/O map word #6)
  2. When ‘User Defined Value’ is selected for Channel 4 and the value is set to a any number other than zero. (4x I/O map word #7)

The other 2 analog output parameter selections, ‘Minimum Output’, and the default parameter ‘Hold Last Value’, do not produce this condition.

Facts and Changes

Units affected are:

  • 170ANR12090
  • 170ANR12091

Causes and Fixes

A firmware solution has been implemented. Modules with an SV of 1.10 and a PV02 have this fix.


  • This is not a field upgradable option. Applications using this module that are experiencing discrete inputs issues using the above mentioned parameters may be exchanged under warranty. With the parameter settings described, the problem will occur when a discrete input is made active. Parameter settings other than those described above will not exhibit this problem.
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