The Allen Bradley 1756-A17 ControlLogix chassis is part of the ControlLogix modular system, designed for use in industrial automation environments. It offers a 17-slot configuration and is commonly used with a range of power supply and I/O modules. This article provides a detailed overview of the installation process, technical specifications, and environmental considerations for the 1756-A17 chassis, based on the manufacturer documentation provided in the source materials.
Overview of the 1756-A17 ControlLogix Chassis
The 1756-A17 is a 17-slot chassis that is part of the ControlLogix family of control systems. It is designed to support high-speed communication between modules and to distribute power to the installed I/O and processing modules. The chassis is available in different series—Series B, C, and D—which vary in temperature ratings and conformal coating options. The chassis is typically used in panel-mounted environments and requires a minimum cabinet size for installation.
According to the manufacturer specifications, the 1756-A17 chassis must be mounted horizontally. It is not compatible with vertical mounting configurations. The chassis is available in two variants: 1756-A17 and 1756-A17K, which differ in their operating temperature ranges and insulation ratings.
Technical Specifications for the 1756-A17 Chassis
The 1756-A17 chassis has several key technical specifications that define its performance and compatibility with power supplies and I/O modules. These specifications are essential for ensuring proper installation and operation of the control system.
| Attribute | 1756-A17 | 1756-A17K |
|---|---|---|
| Backplane current, chassis/slot max @ 1.2V DC | 1.5 A/– | Not specified |
| Backplane current, chassis/slot max @ 3.3V DC | 4 A/4 A | Not specified |
| Backplane current, chassis/slot max @ 5.1V DC | 15 A/6 A | Not specified |
| Backplane current, chassis/slot max @ 24V DC | 2.8 A/2.8 A | Not specified |
| Power dissipation, max | 6 W | Not specified |
| Isolation voltage | Determined by installed power supply and modules | Not specified |
| Slots | 17 | 17 |
| Mounting method | Horizontal only | Horizontal only |
| Cabinet size (HxWxD), min | 50.8 x 96.5 x 20.3 cm (20 x 38 x 8 in.) | Not specified |
| Weight, approx | 2.20 kg (4.8 lb) | Not specified |
| Location | Panel | Panel |
| Wire size | Functional earth ground – 8.3 mm² (8 AWG) solid or stranded copper wire rated at 90 °C (194 °F) or greater; Protective earth ground – 2.1 mm² (14 AWG) solid or stranded copper wire rated at 90 °C (194 °F) or greater | Not specified |
| North American temperature code | T5 (Series B), T4 (Series C) | Not specified |
| IEC temperature code | T4 (Series B), T5 (Series B), T4 (Series C) | Not specified |
| Enclosure type rating | None (open-style) | Not specified |
These specifications indicate that the 1756-A17 chassis is capable of handling significant power loads and is suitable for use with a wide range of power supplies and modules. The chassis is designed for use in industrial environments and must be installed in a properly sized cabinet to accommodate its dimensions.
Mounting the 1756-A17 Chassis
Proper installation of the 1756-A17 chassis is essential for ensuring safe and reliable operation. The manufacturer provides detailed instructions for mounting the chassis, which must be followed to avoid damage to the equipment and to ensure compliance with safety standards.
Cabinet Selection and Mounting Orientation
The 1756-A17 chassis must be mounted in a cabinet with a minimum size of 50.8 x 96.5 x 20.3 cm (20 x 38 x 8 in.) for Series B and C variants. The chassis is designed to be mounted horizontally and cannot be mounted vertically. Vertical mounting is not supported and may lead to improper operation or damage to the chassis or modules.
Mounting Procedure
To install the 1756-A17 chassis, the following steps should be followed:
- Select the appropriate cabinet size based on the dimensions provided in the specifications.
- Securely mount the chassis using only a horizontal orientation.
- Ensure that all mounting hardware is properly tightened to prevent movement or vibration that could affect the performance of the modules.
Cable Clearance and Redundant Power Supply Considerations
When installing the 1756-A17 chassis with a redundant power supply configuration, it is important to ensure that there is sufficient clearance for the 1756-CPR2 cable. The cable has a minimum bend radius of 12.7 cm (5.0 in.), and the chassis must have a minimum clearance of 12.7 cm (5.0 in.) on the left side to route and connect the cable. The redundant power supplies must also have a minimum clearance of 12.7 cm (5.0 in.) below the supply to accommodate the cable.
Connecting Modules to the 1756-A17 Chassis
After the chassis has been installed in the cabinet, modules can be connected to the chassis. The modules must be properly aligned and inserted into the chassis to ensure that they make full contact with the backplane.
Module Installation Steps
- Power off the chassis and any connected power supplies before inserting or removing modules.
- Align the module with the slot on the chassis.
- Gently slide the module into the slot until it clicks into place.
- Verify that the module is securely seated and that the LED indicators are functioning correctly.
It is important to handle the modules with care to avoid damaging the connectors or the module circuitry. Modules should be inserted and removed only when the power is off to prevent electrical surges or short circuits.
Powering On the 1756-A17 Chassis
Once the chassis has been mounted and the modules have been installed, the chassis can be powered on. The following steps should be followed to ensure that the power is applied correctly and that the system functions as intended.
Power-On Procedure
- Verify that all connections are secure and that the modules are properly seated in their slots.
- Switch on the power supply and check for proper LED indications on the chassis and modules.
- Monitor the system for any abnormal behavior, such as unexpected LED patterns or module failures.
If any issues are detected during the power-on process, the power should be turned off immediately, and the connections should be checked for errors or damage.
Environmental Specifications
The 1756-A17 chassis is designed to operate in a range of environmental conditions. The following environmental specifications are provided for both Series B and Series C variants of the chassis.
| Attribute | Series B (1756-A17) | Series C (1756-A17K) |
|---|---|---|
| Operating temperature (IEC 60068-2-1, Test Ad, Operating Cold) | 0…60 °C (32…140 °F) | -25…+60 °C (-13…+140 °F) |
| Operating temperature (IEC 60068-2-2, Test Bd, Operating Dry Heat) | 0…60 °C (32…140 °F) | -25…+60 °C (-13…+140 °F) |
| Operating temperature (IEC 60068-2-14, Test Nb, Operating Thermal Shock) | 0…60 °C (32…140 °F) | -25…+60 °C (-13…+140 °F) |
| Surrounding air max temperature | 60 °C (140 °F) | 60 °C (140 °F) |
| Nonoperating temperature (IEC 60068-2-1, Test Ab, Unpackaged Nonoperating Cold) | -40…+85 °C (-40…+185 °F) | -40…+85 °C (-40…+185 °F) |
| Nonoperating temperature (IEC 60068-2-2, Test Bb, Unpackaged Nonoperating Dry Heat) | -40…+85 °C (-40…+185 °F) | -40…+85 °C (-40…+185 °F) |
| Nonoperating temperature (IEC 60068-2-14, Test Na, Unpackaged Nonoperating Thermal Shock) | -40…+85 °C (-40…+185 °F) | -40…+85 °C (-40…+185 °F) |
| Relative humidity (IEC 60068-2-30, Test Db, Unpackaged Damp Heat) | 5…95% noncondensing | 5…95% noncondensing |
| Conformal coating | No | Yes |
| Vibration (IEC 60068-2-6, Test Fc, Operating) | 2 g @ 10…500 Hz | 2 g @ 10…500 Hz |
| Shock, operating (IEC 60068-2-27, Test Ea, Unpackaged Shock) | 30 g | 30 g |
| Shock, nonoperating (IEC 60068-2-27, Test Ea, Unpackaged Shock) | 50 g | 30 g |
| Emissions | IEC 61000-6-4 | IEC 61000-6-4 |
| ESD immunity (IEC 61000-4-2) | 6 kV contact discharges, 8 kV air discharges | 6 kV contact discharges, 8 kV air discharges |
These environmental specifications indicate that the 1756-A17 chassis is suitable for use in a wide range of industrial environments. The Series C variant offers enhanced protection against environmental factors, including conformal coating for increased durability in humid or corrosive conditions.
ControlLogix Chassis Accessories
To ensure proper operation and maintain system integrity, several accessories are available for use with the 1756-A17 chassis. These accessories include slot filler modules and other mounting components that help to secure and organize the control system.
Slot Filler Modules
Slot filler modules are used to fill empty slots in the chassis and to prevent dust and debris from entering the system. The following slot filler modules are available for use with the 1756-A17 chassis:
| Catalog Number | Description |
|---|---|
| 1756-N2 | Slot filler module for empty slots in standard ControlLogix chassis |
| 1756-N2XT | Slot filler module for empty slots in ControlLogix-XT and ControlLogix-ZXT chassis |
These modules help to maintain the structural integrity of the chassis and reduce the risk of short circuits or electrical interference.
Redundant Power Supply Configuration
For critical applications, the 1756-A17 chassis can be configured with a redundant power supply setup. This configuration provides backup power in the event of a power failure, ensuring that the control system remains operational.
When using a redundant power supply configuration, it is important to follow the manufacturer's guidelines for cable routing and mounting clearance. The 1756-CPR2 cable must be routed with a minimum clearance of 12.7 cm (5.0 in.) on the left side of the chassis to accommodate the cable's bend radius. Additionally, the power supplies must be mounted with sufficient clearance to allow for the cable to be connected without causing stress or damage.
Conclusion
The Allen Bradley 1756-A17 ControlLogix chassis is a 17-slot control system that is designed for use in industrial automation environments. It offers a range of technical specifications that support high-speed communication and power distribution to a wide array of modules. The chassis must be installed in a properly sized cabinet and mounted horizontally to ensure proper operation.
When installing the 1756-A17 chassis, it is important to follow the manufacturer's guidelines for mounting, module installation, and power-on procedures. The chassis is available in different series, each with its own environmental and insulation ratings. Accessories such as slot filler modules and redundant power supplies can be used to enhance the performance and reliability of the system.
By following the installation instructions and specifications provided by the manufacturer, users can ensure that the 1756-A17 chassis is properly configured and operating at peak efficiency.