This Product Notice provides awareness of Global Positioning System (GPS) events that may affect time keeping capabilities of the 1756HP-TIME and 1756-TIME ControlLogix® GPS Time Synchronization modules. The GPS uses fixed size counters to manage various aspects of time keeping. When a counter rolls over (maximum value to zero) time keeping devices dependent on that counter may need to be updated to compensate.

PRODUCT IDENTIFICATION

The potentially affected products are 1756-TIME and 1756HP-TIME GPS Time Synchronization Modules.

• 1756HP-TIME
• 1756-TIME Series A
• 1756-TIME Series B

On installed product, the product identification information may be found on the product nameplate, located on the side of the product module. The catalog number will be on the left side in the CAT field and the as shipped version information in the F/W REV field. Since the firmware version may have been updated in the field after receipt, you should verify the firmware revision using online tools such as Studio 5000 Logix Designer® or FactoryTalk® Network Manager.

In the example shown below, the catalog number is 1756-TIME Series B and the firmware revision is 3.005. Firmware version 3.005 contains the correction for the week counter rollover event and is the correct version as of the release of this notification.

On product still within its shipping carton, the product identification information may be found on the carton label. The catalog number will be on the left side in the CAT field and the as shipped version information in the FW field.

In the example shown below, the catalog number is 1756-TIME Series B and the firmware revision is 3.005. Firmware version 3.005 contains the correction for the week counter rollover event and is the correct version as of the release of this notification.

DESCRIPTION

Future Global Positioning System (GPS) events may affect the time keeping capabilities of the 1756HP-TIME and 1756-TIME ControlLogix® GPS Time Synchronization modules. The GPS uses fixed size counters to manage various aspects of time keeping. When a counter rolls over (maximum value to zero) time keeping devices dependent on that counter may need to be updated to compensate.

A recent rollover event occurred 0n April 6, 2019. The GPS time standard rolled over the week counter to zero. In the GPS, weeks are calculated using a 10-bit counter, giving a maximum of 1024 weeks prior to rolling over to week 0. This correlates to approximately 19.7 years. When the rollover occurred, GPS devices that used this information to calculate time erroneously calculated the week as 0, or 19.7 years in the past. The next week rollover event for devices using this 10-bit counter is expected to occur on September 27, 2036.

As reported by the US Naval Observatory (USNO), “there is an ongoing multi-billion-dollar program of upgrades to improve the overall performance of the Global Position System. Included within this program is a move towards a 13-bit date field to represent the week number. Thirteen binary bits represents around 157 years per epoch. Newer GPS receivers will not be affected by the current end-of-epoch situation”.

Additional information concerning the recent 10-bit week counter rollover event may be found at the Department of Homeland Security and the US Naval Observatory.

Additional future events may have a similar effect on the 1756-TIME module. Rockwell Automation has created Knowledgebase Article ID 1082057 to address this and future events that may affect the 1756-TIME module.

TEMPORARY WORKAROUND

No workaround has been identified for older 1756HP-TIME and 1756-TIME Series A modules. Rockwell Automation encourages customers with older modules to migrate to the current 1756-TIME Series B modules.

CORRECTION

Rockwell Automation will update Knowledgebase Article ID 1082057 when upcoming rollover events result in firmware revisions. Customers are encouraged to subscribe to updates to this article to receive advance notification.

Users of prior 1756HP-TIME and 1756-TIME Series A modules must migrate to the current 1756-TIME Series B module prior to 2021. Migration of older product is at the discretion and cost of the customer.

Users of current 1756-TIME Series B modules should upgrade their module to firmware version 3.005 or later. Updated firmware can be field installed and is available on the Rockwell Automation Product Compatibility and Download Center (PCDC). Access the PCDC at https://compatibility.rockwellautomation.com/Pages/home.aspx. Click the “Find Downloads” link and enter 1756-TIME. Make sure to select the latest firmware release for the Series B module. Follow the instructions to complete the firmware download.

REQUESTED CUSTOMER ACTION

Rockwell Automation requests you take the following actions:

• Check if you have a product affected by this Product Notice. Refer to the Product Identification and Description sections of this document for product identification assistance.
• Follow the steps in the Correction section of this document to make sure you have the latest firmware revision for your 1756-TIME Series B module.
• Prior to installation of new product, verify the firmware level to make sure you have the latest firmware revision.
• If you need additional assistance, please contact Rockwell Automation Technical Support. See Appendix A for local telephone numbers. Customers without TechConnect℠ support contracts should reference this Product Notice when calling.
• Customers with TechConnect support contracts may be able to chat online with support representatives. Reference this Product Notice when connected to a support engineer.