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The Time of Day (TOD) Clock in a Momentum 172PNN2x022 or 172JNN21032 Adapter may be Incorrect After Being Powered Down

Release Notice

The purpose of this resolution is to inform Momentum users of a possible Time of Day (TOD) clock issue with the 172JNN21032, 172PNN21022, and 172PNN26022 option modules. If a time and date function is required in the process, then a JNN or PNN adapter is necessary to be part of the Momentum block assembly.

Goals and Symptoms

An issue has been found with the TOD clock in some 172JNN21032 modules. If the TOD clock feature is configured and the Momentum assembly is powered down, the TOD clock may contain the incorrect time and/or date after the assembly is powered up. In most conditions, the clock time at power up will be incorrect by the amount of time the unit was powered down. In addition to the incorrect time, other TOD fault conditions may also include an incorrect Day of the Week or Year after power up.

* Refer to the 'Facts and Changes' section in this document to determine if a TOD problem exists.

Facts and Changes

PRODUCTS affected:

  • This resolution affects the following adapters with the PV number and the 'Date of Manufacture' (DOM) due to the same TOD circuit design:
Part Number
PV number
Date of Manufacter (DOM)
172JNN21032
PV01
0826 or higher
172JNN21032C
PV02
0826 or higher
172PNN21022
PV04
0936 or higher
172PNN21022C
PV03
0936 or higher
172PNN26022
PV04
0936 or higher

  • The PV and DOM numbers are found on the battery access door of the PNN and JNN adapters.
  • It is not possible to determine which modules within the PV and 'Date of Manufacture' (DOM) range may exhibit the TOD issue unless a power cycle test is performed.

  • How to determine if the TOD clock is functioning normally in a system. (This test is valid only if a TOD clock is configured and a working battery is installed)
    Powering down the processor assembly will be necessary to perform this test. Please check with the proper personnel when it is acceptable to perform this test.

    1. To begin, verify the current Time and Date in the PLC by going online and recording the clock time and date. Once this is recorded, disconnect from online.
    2. Next, power down the PLC for approximately 3-4 minutes.
    3. Power up the PLC and connect online. Verify that the Time and Date are still in the expected range of the PC clock.
    4. If the Time and Date results are correct, then no further action is required.
    5. If the Time and Date results are incorrect by the amount of time the assembly was powered down, then it is recommended that the adapter be exchanged.

  • If an exchange is necessary, reference the Quality Information document IQ102452 when ordering.

Causes and Fixes

It has been determined that the TOD clock processor code was incorrectly installed in some instances. New code is now available in the new TOD clock processors that prevents this situation from reoccurring. Since this code is not field upgradeable, any adapter matching the PV number above and exhibiting the symptoms described, must be exchanged.
The following PV numbers identify new or updated adapters:

Part Number
PV number
Date of Manufacter (DOM)
172JNN21032
PV02 or higher
does not apply
172JNN21032C
PV03 or higher
does not apply
172PNN21022
PV05 or higher
does not apply
172PNN21022C
PV04 or higher
does not apply
172PNN26022
PV05 or higher
does not apply

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