Matching Signal and Power Connectors to Robotic and Other High-Density Industrial Applications

Smart factories are becoming increasingly automated through decentralized intelligence and control, utilizing modular robotic machine concepts. This physical distribution of control functions necessitates connectivity via wires and cables that ensure reliable and secure connectors matched with the environmental demands of the modern factory. Such connectors must have low resistance, adequate contact surface area to handle their rated currents, and strong locking mechanisms to resist vibration and shock. Additionally, they must be easy to assemble and modify, enabling rapid updates and changes.

This article provides a brief overview of the connectivity demands of industrial robots and factory automation. It then introduces a series of connectors from TE Connectivity AMP and shows how their features can be applied to support the power, signal, reliability, and safety needs of these applications.

What is a smart factory?

A smart factory is an integrated facility that uses digitally interconnected machines, robots, and local sensors for control, real-time data collection, analysis, and decision-making (Figure 1). Such factories are becoming increasingly decentralized and modular, allowing them to be easily reconfigured to meet changing production needs. The modular organization favors local control and smaller machines to enhance production flexibility.

Figure 1: The smart factory employs networked machines, robots, and interconnected sensors to ensure efficient operation. (Image source: TE Connectivity AMP)

These facilities use modular workstations equipped with independent or collaborative robots (cobots). Mobile robots, such as automated guided vehicles (AGVs) or autonomous mobile robots (AMRs), move products between workstations. AMRs and AGVs have the advantage over stationary robots in that they are highly mobile and can rotate and translate between and among workstations. With AGVs, AMRs, and cobots working together, a production line can have different tasks taking place within separate cells. Robots can pivot between workstations or be reassigned as needed, thereby improving overall efficiency. These workstations are frequently located in harsh environments, so designers must factor in that robots and other automated machines may be exposed to high temperatures, humidity, dust, corrosive chemicals, and shock and vibration.

Sensors monitor all operations. Depending on the design, the sensors may be wired or wireless. Wireless sensors are commonly connected via the Industrial Internet of Things (IIoT). Mobile robots are also monitored and controlled using the IIoT.

As is typical of electronic systems, the industry trend is toward smaller robots, machines, sensors, and controllers. The small size and light weight translate into lower power requirements and more available floor space for increased production. They also translate to smaller printed circuit boards (pc boards), which require components with high volumetric efficiency.

Flexible and reliable power and signal connectors

Connectors, whether wire-to-wire, wire-to-board, or wire-to-panel, must reliably carry power and control signals. Smaller connectors result in closer spacing and a finer conductor pitch.

Modular design, by definition, is flexible; therefore, the connector solutions must be as adaptable as the automated system. Consistent with the need for flexibility, connectors must be designed to ensure secure and convenient locking that prevents both mis-mating during assembly and accidental unplugging resulting from shock and vibration.

TE Connectivity AMP’s Dynamic series connectors are designed to meet the needs of industrial signal and power circuits that require high density. The connectors meet these requirements through several connector series, which handle currents ranging from 2.6 to 100 amperes (A) and voltages from 125 to 1000 volts. Depending on the current and voltage ratings, these connectors offer high-density interconnections with conductor pitches from 1.8 to 24.5 millimeters (mm).

The most compact Dynamic connectors are the Mini series. Intended for wire-to-board applications, this series has a contact pitch of 1.8 mm and is available with pin counts of 12, 16, and 20 positions. Accepting wire sizes of 22 to 26 AWG, they are rated to handle 250 volts AC (VAC) at 3 A.

An example is the 1-2834461-2 (Figure 2, top), a 12-contact receptacle housing with the contacts arranged in a double row with a row-to-row spacing of 2.75 mm. The connector measures 19.3 mm in length, 15.7 mm in width, and 8.35 mm in height.

Figure 2: Shown are the elements of a 12-pin Dynamic Mini cable-to-board receptacle (top) and header (bottom). (Image source: TE Connectivity AMP)

The receptacle housing is populated with TE Connectivity AMP 2834464-5 receptacle contacts. These are tin-plated copper alloy crimped wire terminals that accept 26 AWG wires. They are rated to handle 3 A at a working voltage of 250 V_AC or 125 V_DC. Each contact uses a locking lance to anchor itself in the housing. Additionally, the housing features a flush-mounted secondary lock to provide an extra layer of security for the contact terminal's locking mechanism.

The receptacle mates with the 1-2834465-2, a 12-pin surface mount header (Figure 2, bottom). The header has a length of 19.3 mm, a width of 12.3 mm, and a height of only 8.7 mm. The header includes square cross-section tin-plated contact pins that are fully shrouded.

The connector pair is keyed to prevent incorrect insertion and features a locking latch that provides audible and tactile feedback when the receptacle and header are fully engaged. The latch is sunken below the top of the connector to prevent accidental unlatching. Side pegs provide mechanical support for the header.

The smaller size and higher reliability of the Mini series connectors meet the requirements of not only the industrial environment, but also other applications such as robotics and automotive, which require higher vibration resistance.

Connectors for higher current

The connector size increases to accommodate the need to handle higher currents. The Dynamic D1000 Slim connectors (Figure 3) fill the niche for the next higher current range. For example, the 1-2366600-4 is a two-row, four-position plug housing with a contact pitch of 2.7 mm and a row-to-row spacing of 2 mm. This plug housing mates with the 1-2366515-4 receptacle housing for a wire-to-wire inline connection. Like the Mini series connectors, the D1000 includes a latch that has both audible and tactile feedback to ensure positive engagement. Both receptacle and tab crimp contacts are available, handling wire sizes from 22 to 30 AWG. The D1000 connector is rated for a maximum current of 8.3 A, depending on the selected wire gauge.

Figure 3: Shown is the assembly of a four-position D1000 Slim wire-to-wire connector. (Image source: TE Connectivity AMP)

The housings are available with either horizontal or vertical keying to ensure proper mating. The mated connector set measures 21.5 mm in length, 7.2 mm in width, and 8.9 mm in height. The housings are clearly labelled with both the row identification and key type to minimize configuration and wiring errors (Figure 4).

Figure 4: Shown are the row identification and key orientation markings used for D1000 Slim housings. (Image source: TE Connectivity AMP)

Field installation

The Dynamic series includes a broad range of connector types, in addition to crimp contact versions. Cage or spring clamp connectors, such as the D-2970 series (Figure 5), are also available. The spring clamp connectors, unlike crimp contact connectors, are easy to install or modify on-site. Wires, with end insulation removed, are inserted into the connector body wire entry port, where a spring-loaded clamp engages the wire and locks it in place. A release button allows the inserted wire to be removed. No tools are required to wire or de-wire the connector.

Figure 5: The wire-to-board D-2970 series connectors can be wired without tools by simply inserting a stripped wire into the wire entry port. (Image source: TE Connectivity AMP)

Examples of the D-2970 series include the 2336491-4, a four-contact, single-row header that mates with the 2336488-4 four-position receptacle connector for wire-to-pc board assembly. The connector pair features a 5 mm contact pitch and accommodates wires ranging from 14 to 24 AWG, capable of handling a maximum of 14 A based on the selected wire gauge. They are rated for voltages as high as 300 V.

The header measures 22 mm in width, 34 mm in depth, and 18.7 mm in height, while the receptacle measures 24.9 mm in width, 14.8 mm in depth, and 9.8 mm in height.

Conclusion

Industrial power and signal connectors for robotics and factory automation must be carefully selected to ensure reliability, safety, flexibility, and signal integrity. TE Connectivity AMP Dynamic series connectors enable designers to choose from a broad range of pin configurations, emphasizing features such as high density, keyed housing, clear markings, locking capability, shock and vibration resistance, and compact size.