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Description:

The 1756-HSC is a two-channel high-speed counter module in the Allen-Bradley 1756 ControlLogix family, manufactured by Rockwell Automation for direct, controller-independent counting of fast pulse-train signals in industrial automation systems. Each counter accepts three inputs (A, B and Z for gate/reset) and drives two sourcing DC outputs per channel, so one single-slot module captures quadrature encoder, proximity-sensor and photoelectric feedback at up to 1 MHz in counter mode while delivering high-speed output control in parallel.roccommerce.net+1

Configured natively inside Studio 5000 Logix Designer and occupying one standard 1756 chassis slot, the 1756-HSC offloads pulse accumulation, frequency measurement and preset-triggered output switching from the controller scan cycle — protecting count integrity on applications where even a single lost pulse is unacceptable.rockwellautomation.com

Application Scenarios:

Picture a high-speed converting line producing perforated film rolls: a rotary encoder feeds 4 000 pulses per revolution into the control system, and a knife must fire within a fixed number of counts — every pass, every shift, without dropping a pulse. The engineering pain points are instantly recognizable to anyone who has tried to wire a fast pulse train into a standard digital-input card: scan-cycle latency that misses pulses at high frequency, count rollover errors, no hardware-based preset triggering, and a knife output that fires late because the controller was busy with other tasks. The 1756-HSC was engineered precisely for this class of application — pulse counting happens entirely on the module at up to 1 MHz in counter mode (250 kHz in encoder X4 mode), the Z input provides hardware gate/reset without controller intervention, and the four sourcing outputs fire on preset values set directly in the module’s configuration, independent of controller scan timing.roccommerce.net+1

The 1756-HSC therefore becomes the natural choice for flow totalizers on turbine meters, length-cut counters on rotary shears, batch counters on bagging machines, overspeed detection on rotating equipment, and registration tracking on print-and-apply labelers — anywhere the pulse train is faster than a standard DC input module can reliably catch, and anywhere a hardwired preset output is needed without PLC latency.industrialmonitordirect.com+1

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Application Scenarios

In a wide-area pipeline monitoring network stretching across hundreds of kilometers, sequence-of-events (SOE) recording becomes meaningless if the timestamps from different compressor stations cannot be correlated to a common time base. Each station’s ControlLogix chassis hosts a 1756HP-GPS module connected to a roof-mounted active antenna. When a pressure anomaly triggers alarms at three separate stations within a 200-millisecond window, the 1756HP-GPS modules at each site provide UTC timestamps accurate to the microsecond level, allowing the central SCADA system to reconstruct the exact propagation sequence of the event and determine whether the anomaly originated upstream or downstream. Without this satellite-disciplined time reference, the investigation would be reduced to guesswork based on unsynchronized local clocks .

For a utility grid substation where protective relays and merging units must align their sampled values within microseconds, the 1756HP-GPS serves as the local time master when the station‘s PTP grandmaster is unavailable or when the utility requires an independent, satellite-traceable time source that does not depend on the corporate IT network. The module’s holdover performance of 1 µs/s drift means that even if the antenna cable is damaged during a storm, the chassis maintains sufficient timing accuracy for several minutes while maintenance responds .

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Description

The 1756-ESMCAP​ is the capacitor-based Energy Storage Module (ESM) that ships fitted to every Allen-Bradley ControlLogix 5570 controller — the 1756-L71 through L75 and their GuardLogix L7 siblings. It is not a battery and it is not an I/O module. It is a small, controller-mounted supercapacitor pack that catches the falling edge of a power loss and buys the processor the few seconds it needs to finish writing its program, data tables and WallClockTime to non-volatile memory.What makes the 1756-ESMCAP​ worth specifying is what it quietly removes from the maintenance plan: no lithium cell to age, no two-year replacement cycle, no electrolyte leak down the side of a £15,000 CPU, and no “red BAT LED at 2 a.m.” because a battery tray was keyed for the wrong series. Rockwell replaced the 1756-BA2 era with exactly this part, and the L7x controller is designed around it .

Application Scenarios

A control engineer on a North Sea platform once described the old failure mode with the kind of precision only a pager-duty veteran has: “The battery didn’t fail. The tray did.” A 1756-BA2 in a humid, vibrating rack had sweated its terminals, the cell voltage collapsed during a routine switchover, and the next unscheduled trip wiped the L6x program. The restart took nine hours, six of them spent proving the logic was still on the laptop and the other three re-sequencing the line.The 1756-ESMCAP​ is the answer to that specific class of failure. On a modern L7x rack, a capacitor does not care about humidity, orientation or a ten-year sit on the shelf — its chemistry does not dry out. When the 24 V supply dips, the controller sees the event, the 1756-ESMCAP​ discharges through the internal bus, and the save cycle runs to completion before the last of the charge is gone. The operators see a bump on the SCADA trend and a controller that comes back with its recipe, its fault history and its clock intact. Nobody opens a battery log, because there is no battery.

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Description

The 1756-EN3TR is a ControlLogix EtherNet/IP communication module from Allen-Bradley (Rockwell Automation), distinguished from the standard 1756-EN2TR by its extended integrated motion capability. While it performs the same core functions as the EN2TR for I/O and messaging, the 1756-EN3TR supports up to 128 motion axes over EtherNet/IP, making it the choice for ControlLogix applications where servo drives and coordinated motion share the same network as standard I/O . The module features dual copper RJ45 ports with an embedded switch, enabling device-level ring (DLR) topologies without external switches.

Application Scenarios

A machine builder designing a multi-axis packaging line uses a ControlLogix chassis as the line controller. The line includes twelve Kinetix servo axes for forming, sealing, and cutting stations, plus remote I/O drops for pneumatic valves and sensors. Rather than adding a separate motion network module alongside a standard Ethernet bridge, the builder installs a 1756-EN3TR in the ControlLogix rack. The module’s dual ports connect into a DLR ring that includes the servo drives and remote I/O, providing media redundancy so a single cable break does not halt production. The 1756-EN3TR handles both the implicit CIP Motion traffic for the twelve axes and the standard EtherNet/IP I/O and messaging traffic, simplifying the network architecture and reducing the number of modules, cables, and managed switches required in the panel.

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Description

The Allen-Bradley 1756-EN2TXT​ is a chassis-based EtherNet/IP communication bridge for the ControlLogix-XT family, built by Rockwell Automation. It occupies a single slot in an XT-series rack and acts as the routing engine between the controller’s backplane and the plant’s Ethernet: real-time I/O, produced/consumed tags, explicit messages, HMI traffic and motion data all share the same two copper ports.Where the standard 1756-EN2T​ stops at 60 °C, the 1756-EN2TXT​ keeps going to 70 °C and down to −25 °C, with the XT conformal-coating and corrosion-resistance treatment that the “XT” suffix promises. It is the same dual-port, 10/100 Mbps, 256-CIP-connection module — just one that will still be passing packets after a summer heat-soak in an unventilated desert panel or a salty coastal compressor house.

Application Scenarios

An LNG terminal on the Bohai Gulf had its ControlLogix rack in a locally air-conditioned skid room that was anything but. On August afternoons the cabinet interior touched 66 °C, and the standard-temperature bridge would trip its internal thermal margin, drop the produced/consumed tag link to the gas-analysis skid, and hand the operator a stale-data alarm that looked exactly like a process upset. The operations team had learned to “cycle the switch” — which is another way of saying the network was being rebooted by the weather.The fix was a 1756-EN2TXT​ swapped into the same slot, same firmware family, same Studio 5000 module definition. No program changes, no new IP scheme, no re-run cable. The XT module sat through the next heat wave with the link LEDs steady and the port-crc counter clean. More usefully, the plant could now prove the instrument skid data was live, so a genuine process deviation stopped getting buried under false staleness. The panel tech’s verdict was characteristically short: “It used to die when the sun came up. Now it just gets warm.”That is the 1756-EN2TXT​ doing the job it was named for — not faster networking, but networking that refuses to notice the environment.

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Product Overview

The Digitronic 1756-DICAM — marketed as the CamCon DC1756 — is a high-performance digital cam switch unit (programmable limit switch, PLS+) engineered by Digitronic Automationsanlagen GmbH in Germany to plug directly into the Allen-Bradley ControlLogix 1756 chassis. Available through the Rockwell Encompass program, the 1756-DICAM serves as a dedicated Boolean processor that executes cam-switching logic entirely on its own Motorola ColdFire CPU, entirely independent of the ControlLogix controller’s scan cycle. This architecture delivers switch-on/switch-off reaction times of approximately 70 microseconds, ensuring that outputs transition at precisely the programmed angular or linear position regardless of controller loading — a level of determinism that conventional PLC output modules cannot matchhvsgroup.fr+2.

Electronic cam switching replaces mechanical camshafts, limit switches, and rotating cam stacks with fully programmable electronic precision. The 1756-DICAM provides 24 galvanically separated, short-circuit-proof 24V DC outputs (0.2A each, 0.4A at 50% duty) and 8 galvanically separated inputs as standard, with total I/O expandable to 200 inputs and 200 outputs through the external interface when paired with Digitronic expansion modules. Standard configuration supports 1,200 programmable cams, expandable to 4,000 or even 10,000 cams depending on the selected EEPROM memory option (16 KB, 48 KB, or 128 KB), with up to 32,768 program slots for product-specific cam-set libraries and rapid format changeovertcisupply.com+1.

Position feedback is accepted through a rich suite of measuring-system interfaces: SSI absolute encoders (Stegmann SSI standard, up to 300 m cable, with a 1000 m option), incremental 24V PNP or Hiperface signal inputs, and parallel measuring systems. Speed-dependent actuators are handled by the built-in delay-time compensation (0 to 9,999.9 ms) and non-linear speed compensation, ensuring that glue nozzles, cut-off knives, ejectors, and valves fire at the same physical location across the full speed range of the machine. Although the 1756-DICAM is now designated discontinued-by-manufacturer, the substantial installed base in packaging, printing, converting, and metal-forming machinery worldwide makes it a continuing priority for MRO stocking and lifecycle replacementtcisupply.com+2.

Technical Specifications

Technical Specifications

Main Features and Advantages

Dual-Channel Flexibility for Mixed Network Architectures: The 1756-DHRIO allows each channel to be independently configured as DH+ or RIO, enabling a single module to serve as both a DH+ bridge to legacy PLC-5 systems and an RIO scanner for remote I/O racks. This dual capability reduces the number of modules required in a ControlLogix chassis, conserving slots and simplifying network topology. Channel A is typically used for DH+ when programming terminal access is needed, as its front-panel connector supports direct connection.

Seamless Integration with Legacy Allen-Bradley Platforms: The 1756-DHRIO bridges ControlLogix controllers to PLC-5 and SLC 5/04 processors over DH+ networks, allowing message instructions (MSG) to exchange data between disparate controller families. This capability is critical for phased migration projects where new ControlLogix hardware must coexist with existing PLC-based control systems. The module also supports CIP bridging, enabling messages from Ethernet or ControlNet devices to reach DH+ nodes through the routing table.

High-Capacity RIO Scanning for Distributed I/O: When configured as an RIO scanner, the 1756-DHRIO supports up to 32 logical rack connections per channel, accommodating large distributed I/O systems with multiple remote adapters. The module distributes control so that each controller maintains ownership of its own I/O, supporting deterministic data exchange for time-sensitive applications. Block transfer capability (16 connections per channel) enables analog and specialty I/O modules to be integrated into the RIO network alongside discrete I/O.

Robust Routing and Gateway Functionality: The 1756-DHRIO can route messages through up to four networks and three chassis, allowing devices on DH+, ControlNet, Ethernet, and other networks to communicate as if locally connected. This routing capability eliminates the need for external gateway devices in many configurations, reducing hardware costs and points of failure. The module’s routing table is configured through RSLogix 5000 or Studio 5000 and must be carefully documented for maintenance and replacement purposes.

Product Overview

The 1756-CP3_A​ is the fan-tray cable assembly for the Allen-Bradley ControlLogix chassis family, manufactured by Rockwell Automation as the small but critical harness that delivers 24 V power to the chassis cooling fan and returns the tach/fault sense back to the backplane monitor. In a ControlLogix rack the fan is not a comfort item — it is a declared part of the thermal design. The modules run hot, the bus draws current, and the chassis is rated on the assumption that air is moving at the designed CFM. The 1756-CP3_A​ is the only thing connecting that airflow to the controller’s ability to know it is there; when the harness fails, the chassis sees a fan fault and the system goes into the derate and alarm behaviour defined by the installation manual, even if the fan blades are still spinning.What makes the 1756-CP3_A​ worth carrying as a spare is the way it fails. The cable lives in a hot, vibrating environment right behind the fan’s airstream, and the connector is the weak point: the locking latch cracks, the keying tab shears off during a careless pull, or the crimped pins loosen until the tach signal floats. The result is an intermittent “chassis fan failed” major fault that clears and returns on a temperature cycle — exactly the kind of ghost fault that gets blamed on the processor or the power supply. Replacing the whole fan tray is expensive and usually unnecessary; a 1756-CP3_A​ swap restores the sense circuit and the clean 24 V feed in minutes, with no module removal and no control-program change.The assembly is also a favourite of the retrofit and field-upgrade crowd. When a 1756-A3 or A4 frame has been moved from a clean office panel into a hot motor-control centre, or when a site has added high-density I/O and pushed the chassis past its original cooling margin, the 1756-CP3_A​ is inspected, extended or replaced as part of bringing the thermal design back into spec. Keeping a tested, keying-matched 1756-CP3_A​ on the truck means the technician does not improvise a harness with spade lugs — a shortcut that works once and then cooks a rack during the next heatwave.

Technical Specifications

Main Features and Advantages

A harness that actually protects the rackThe quiet value of the 1756-CP3_A​ is that it closes the monitoring loop. Powering a fan from a random 24 V tap will keep the blades moving, but it will not tell the chassis the fan is moving, and ControlLogix treats an unconfirmed fan as a failed fan. The sense pair in the 1756-CP3_A​ is what lets the backplane clear the fault honestly. That is the difference between a panel that alarms on schedule and one that alarms because someone got clever with the wiring.Fit, keying and length that prevent field damageA harness is not a commodity when the connector is keyed to one orientation and the wire length is part of the strain relief. The 1756-CP3_A​ is cut and dressed for the 1756 frame so the fan tray seats without pinching the cable against the backplane or kinking it across a sharp chassis edge. The latching housing is designed to survive repeated fan-tray pulls during module work; a non-keyset replacement inevitably gets forced, and a forced connector is how pins get pushed back into the plastic and turn into intermittent faults. We match the revision and the key before we ship, because a 1756-CP3_A​ that almost fits is worse than no spare at all.The cheapest insurance in the panelThere is no configuration, no firmware and no addressing involved — a 1756-CP3_A​ is pure mechanical and electrical recovery. For that reason it is the highest-return item on a ControlLogix spare list after a spare power supply. A chassis that is overheating because of a broken fan harness will eventually trip modules offline in the middle of a campaign, and the root cause will be misdiagnosed for a day before someone opens the fan tray. A two-minute swap with a 1756-CP3_A​ in the stores cabinet ends the story before it starts.

Application Field

The 1756-CP3_A​ is found wherever a ControlLogix rack is mounted in a working industrial environment rather than a lab bench: motor-control centres beside hot transformers, packaging lines where the panel shares an enclosure with VFD heat, food and beverage washdown rooms where thermal cycling is aggressive, and outdoor skids where summer ambient already eats half the chassis margin. In these settings the fan runs continuously and the harness takes the full vibration of the plant, which is why a cracked latch or a loose tach pin is a routine failure rather than a rarity.The cable also matters during commissioning and panel rework. When a 1756 rack is relocated to a deeper enclosure, or when a contractor adds a second power supply and a dense block of analog input modules, the original airflow path is disturbed and the fan works harder — which is precisely when a tired, six-year-old harness chooses to fail. Running a fresh 1756-CP3_A​ as part of the rework, and dressing it exactly along the factory route, keeps the thermal design honest and the major-fault log quiet. For service organisations supporting fleets of Logix panels, the part is also a useful diagnostic differentiator: before swapping a processor, a power supply or an I/O module on a thermal alarm, check the fan and the 1756-CP3_A. Most of the time the fix is in the tray, not in the rack.

Technical Specifications

Main Features and Advantages

Redundant Media Support for Critical Networks: The 1756-CN2R distinguishes itself from the standard 1756-CN2 by providing two ControlNet BNC ports, enabling connection to both the primary and redundant cable paths of a ControlNet network. In the event of a cable break or connector failure on one trunk line, the module maintains communication over the alternate path, preventing a single point of failure from disrupting I/O control or inter-controller data exchange . This redundancy capability is essential in continuous-process industries where network downtime translates directly into lost production.

High Connection Capacity for Complex Architectures: The 1756-CN2R supports 128 Logix communication connections for standard use, a substantial increase over the 64-connection limit of earlier ControlNet modules such as the 1756-CNB and 1756-CNBR . This expanded capacity allows the module to handle larger I/O configurations, more produced/consumed tag exchanges between controllers, and additional messaging connections without exhausting connection resources. For systems integrating multiple ControlLogix controllers and extensive distributed I/O, the 1756-CN2R provides headroom that reduces the need for additional communication modules.

Integrated USB Port for Local Access: The 1756-CN2R includes a USB 1.1 Type B port that provides local programming and diagnostic access without requiring a network connection . Maintenance personnel can connect a laptop directly to the module for firmware updates, configuration changes, or status checks, which is particularly useful during initial commissioning or when the ControlNet network is unavailable. The USB port is intended for temporary local use only, and cable length should not exceed three meters.

Compatibility with ControlLogix Redundancy Systems: The 1756-CN2R is designed to operate within ControlLogix redundant chassis configurations, where paired modules in primary and secondary chassis maintain synchronized communication with the ControlNet network . When a controller switchover occurs, the redundant communication path and paired module configuration help ensure that I/O and messaging continue without interruption. This capability makes the 1756-CN2R suitable for applications in power generation, water treatment, and other processes where controller availability is a primary design requirement.

Product Overview

The Allen-Bradley 1756-A17​ is the largest of the standard ControlLogix chassis, Bulletin 1756, and it exists for one reason: to hold a complete local control node in a single backplane. Seventeen module positions is not a cosmetic number — it is the difference between a controller, two communication modules, a block of analog I/O, a safety segment and still having room for the next network or the next transmitter bank without moving to a second remote rack. The 1756-A17​ is a passive backplane structure with no active electronics of its own, which is precisely why it is so dependable: the mechanical frame, the card guides, the P1 power connector and the backplane traces are the whole product, and there is nothing in them to firmware-update or burn out.What the backplane does is twofold. Electrically, it distributes four regulated rails from the left-end power supply to every slot: 1.2V DC at 1.5 A chassis maximum, 3.3V DC at 4 A, 5.1V DC at 15 A chassis / 6 A per slot, and 24V DC at 2.8 A chassis / 2.8 A per slot. Communicatively, it is the producer/consumer fabric across which a 1756-L85​ or 1756-L83​ controller reaches an 1756-EN3T​ port, an 1756-IF16​ analog input block, a 1756-IB16S​ safety card and a 1756-DHRIO​ legacy bridge in the same chassis, with backplane message routing moving data between modules without leaving the rack. Any module fits any slot, so a 1756-A17​ ordered for a 12-module system today can absorb five more modules over the next decade without a chassis change, a cable re-run or a re-approval of the panel layout.Physically the 1756-A17​ is a horizontal-only, back-panel-mount frame: 738 mm wide, 169 mm high and 145 mm deep, roughly 2.2 kg empty, demanding a minimum enclosure of 762 × 914 × 203 mm (30 × 36 × 8 in.). That footprint is honest about the air it needs. Convection cooling relies on the chimney formed by the module heat sinks, which is why empty slots must be closed with 1756-N2​ filler strips — an open slot breaks the airflow lane and quietly derates the ambient capability of the modules on either side. The chassis is currently an Active, Preferred product, with Series C the current build and Series B still widespread in the field; both accept the same module set, and the Series C frame added a second ground screw and tougher mounting-tab geometry for high-vibration cells. For a plant standardising on ControlLogix, keeping a bare 1756-A17​ on the spare shelf is the cheapest form of insurance against a rack-expansion outage.

Technical Specifications