SWITCHMAX® connectivity continues to evolve to cover a wide variety of interfaces, options, and applications. With design roots in the molding industry, mold sensor connectivity is still an excellent example of SWITCHMAX® success – connecting multiple sensors to a single input – multiple core position sensors to the single set and single pull input on an injection molding machine. Not surprisingly, the need to integrate multiple sensors only becomes more common as the ever-increasing automation demands intersect with IO limited designs and legacy systems.
Can we plug in a “gizmo” that easily lets us put on more sensors and interface easily with the limited machine control?
YES! The “gizmo” is SWITCHMAX®…
While not often considered, integration with a simple control system interface requires combining many position switch and sensor “on” signals into a single input signal. The need for simple signal integration is everywhere. Fundamentally, the machine “needs to know” when all the appropriate indications are “made” for the next step in the process. The control’s single input is the place where that will be “made known” to the machine.
Integrating different sensors and switches
While the terms are often used interchangeably, switch often refers to devices with mechanical actions and sensor to devices that use “electronics only”. Many mechanical switches look mechanical, while a few have the shape of a solid-state device. Regardless of outward appearances, mechanical switches and proximity sensors, employ differing technologies not easily linked together.
Proximity sensors require power and individual connections to inputs on the PLC. Each sensor has an individually supplied voltage (+ and -) and a separate signal path to the control. The PLC/control software programming integrates senor signals for proper machine indication, offering smaller sizes at a relatively low cost.
Mechanical sensors (switches) pass signals through a two-wire contact and do not require power to operate. Limited to signals only, switches easily combine in series to pass a signal to the control. Mechanical switches are often large, relatively more expensive, and commonly added to products for ease of wiring.
SWITCHMAX® integrates both proximity and mechanical sensors into a common system, providing the necessary single channel outputs, allowing more freedom to select products with sensors, and supporting upgrades to input-limited and legacy systems.
Adding Light indication and modular simplicity
For any system, this goal is often defeated in swappable subsystem arrangements where sensor quantities vary. Routing sensor inputs independently to the machine would require specific programming for each subsystem. In injection molding for example, molds are the subsystem. Each mold has differing quantities and styles of sensors.
As the Injection Molding Machine (IMM) limits the input to the control to one signal, mechanical switch sensors are easy to connect in series, and proximity sensors have complex power needs and connectivity, the use of mechanical switches for injection molds is popular. However, while series connections allow for simple wiring and connection to single input controllers, they do not show individual switch positions or track continuity. Also, many new products operate exclusively with proximity sensors, making the addition of mechanical switches costly. In all cases, troubleshooting out of position components or sensor/switch failures is extremely difficult for larger systems, even for those familiar with the wiring scheme. Troubleshooting for those unfamiliar with the wiring plan, may be overwhelming.
To control this randomness, some standardization on specific components such as sensors and machine interface plugs is helpful. However, standard components are often combined with connections using custom layouts, complex documentation, unique drawings, unexpected wire colors, and undocumented multiple point methods such as terminal blocks or wire nuts. When these wiring networks, often described as spaghetti networks, stop working, they continue to be the source of daily intractable problems that erode productivity and profitability.
SWITCHMAX® Connectivity is the Ideal Solution:
The ideal solution would be an off the shelf system providing replaceable “plug and play” components, light indications for all sensors/switches, which also covers all possible situations, integrates easily with standard sensor technology already in use, and is simple for users to implement, troubleshoot, and repair quickly with minimal effort. SWITCHMAX® connectivity is the ideal solution.
Multiple Sensor Inputs – Combines single “on” sensors or “two position” sensors to single inputs. Applications may have single position output sensors (on/off) or may have multiple output switches (forward/back). Specific yet common cables are used to integrate a variety of sensors together, so that regardless of which cable you need, the cable is selectable from common stocks, plug and play ready, and easily swapped out.
Multiple Sensor Styles – Combines Plunger and Rocker (SPDT) style and Solid-state (PNP) sensors.
Plunger, Rocker, and other Dry Contact/Relay Switches (Form C SPDT) can be combined with 3 wire DC proximity Sensors (PNP) to allow for connecting sensors and switches from a variety of manufactures. Some applications require legacy and alternative control inputs, including AC power and zero voltage DC (sinking) inputs. SWITCHMAX® can accommodate those needs with standardized adapters.
Redundant Sensor Inclusion.
Backup sensors for reading specific equipment position, such as direct core measurement on injection molds, is easily integrated with other sensors. Many backup systems are single indication and need to combine with two-position indication main indicators. Common cables and modular connectors provide this function.
Sensor Connectors – Field Wireable Connectors
Many sensors in common usage have terminal connections or bare wires. Field wireable Connector (FWC) plug ends and short wired plug dongles are available to add standard plugs to sensors for easy linking to other SWITCHMAX® components. Converting hand-wired equipment to standard connectors provides easy replacement when parts are damaged. It eliminates the need to understand schematics, as the new equipment matches the old and the wireable plugs are easily replaced.
Multiple Input Controller Adaptability
Relay Sensor Adapters (SM-RSA) and Relay Power Adapters (SM-RPA) provide interfaces that ensure easy connectivity between the sensors and downstream control inputs. Relay Sensor Adapters can be placed on sensor side installations to bring together complex hubs of different sensor/switch groups and connect them to sourcing or sinking single input controls. Relay Power Adapters are machine side solutions, often providing an independent power supply and neutral wire where none is available or converting the machine to a more desirable electric configuration.
Junction Box/Hub with LED lights
Multiple sensor locations route to a SWITCHMAX® integration hub (Junction Box), which can be located for maximum visibility and ease of access. LED light indication of sensor status is clearly visible and lights are connected in series to aid in troubleshooting position sensing issues or unexpected readings. If a sensor/switch is out of position, the signal will not continue onward to the next sensor, allowing personnel to easily see the out of position location and check the machinery and switch for positioning or electrical issues.