Purchase now: Allen-Bradley 1756-TIME Synchronization Module
Purchase now: Atlantechdrives provides you the 1756-TIME, a highly specialized and critical precision time synchronization module engineered by Rockwell Automation for the ControlLogix 1756 programmable automation platform. In massive, highly distributed industrial control systems, having all PLCs, remote I/O racks, and SCADA servers operating on the exact same microsecond clock is not just a convenience—it is a strict operational requirement. The 1756-TIME module serves as the ultimate Grandmaster Clock for the entire industrial network. By acquiring ultra-precise Universal Time Coordinated (UTC) data directly from the Global Positioning System (GPS) satellite constellation or through external IRIG-B timecodes, this module accurately synchronizes the internal backplane clock of the ControlLogix chassis. This absolute time alignment is mandatory for critical applications such as Sequence of Events (SOE) recording in power generation plants, precise CIP Motion control in high-speed packaging, and accurate alarm timestamping across sprawling petrochemical facilities, ensuring engineers know exactly which valve failed first during a catastrophic plant trip.
Technical Specifications of the 1756-TIME
The 1756-TIME module acts as an IEEE 1588 Precision Time Protocol (PTP) Grandmaster across EtherNet/IP networks, taking the incredibly accurate GPS satellite time and cascading it down to every compatible device on the factory floor with sub-microsecond accuracy.
- Part Number: 1756-TIME
- Platform: ControlLogix 1756 System
- Primary Time Sources: GPS Antenna, IRIG-B (AM or DC), PTP (IEEE 1588), NTP
- Time Output Protocols: PTP (CIP Sync), NTP, IRIG-B, 1PPS (Pulse Per Second)
- GPS Antenna Interface: TNC connector (Antenna and coax cable required, sold separately)
- Synchronization Accuracy: Microsecond to sub-microsecond level (depending on network topology)
- Backplane Current Draw: 350 mA at 5.1V DC
Expert Installation Advice: GPS Antenna Placement and Cabling
The performance of the 1756-TIME module relies entirely on the quality of its GPS signal reception. Expert Tip: When designing your system, the active GPS antenna must be mounted externally with a clear, 360-degree, unobstructed view of the sky. Signal degradation is the most common cause of time sync failure. You must carefully calculate the coaxial cable run between the antenna and the ControlLogix cabinet. Standard RG-58 or LMR-400 coaxial cables have significant signal attenuation over long distances. For runs exceeding 30 meters (100 feet), you may require an inline GPS signal amplifier. Furthermore, because the antenna is mounted outside, you must absolutely install an inline coaxial lightning arrestor where the cable enters the building, properly grounded to the facility’s earth. Without a lightning arrestor, a nearby strike will travel down the coax, instantly destroying the 1756-TIME module and potentially the entire PLC chassis.
Configuration: Establishing the PTP Grandmaster
In a complex Rockwell architecture with multiple time-capable devices, you cannot simply plug the module in and assume it works. You must configure the PTP priorities within Studio 5000. The 1756-TIME must be designated as the primary Grandmaster Clock for the CIP Sync network by lowering its PTP Priority 1 and Priority 2 values (lower numbers mean higher priority). Ensure that the local ControlLogix CPU and communication modules (like the EN2T or EN3TR) are configured to synchronize to the backplane, allowing the 1756-TIME to correctly push its satellite-derived clock data across the entire EtherNet/IP infrastructure.
Frequently Asked Questions (FAQs)
Q: Does the 1756-TIME module come with the GPS antenna included in the box?
A: No. The 1756-TIME is solely the chassis module. The active GPS antenna, mounting hardware, coaxial cabling, and surge protectors must be sourced and purchased separately based on the specific physical requirements of your facility.
Q: Why can’t I just use the internal clock of the ControlLogix L7 or L8 CPU?
A: Internal CPU real-time clocks suffer from «clock drift» and will lose or gain several seconds per month. Furthermore, standard CPU clocks cannot synchronize multiple separate chassis across a massive plant with microsecond accuracy. The 1756-TIME completely eliminates drift by constantly correcting the time via atomic satellite clocks.
Do you need more references from this brand? Explore our full catalog of Allen-Bradley here.
This high-accuracy time synchronization module is technically essential for Sequence of Events (SOE) logging with a ControlLogix 5580 controller.
