Bimba Manufacturing Co. *

Switches

Bimba offers Hall Effect, Magnetic Reed, Magnetic Reed/Triac-type, and Low Profile (giant magnetoresistive - GMR) switches to meet a wide variety of customer needs. Bimba actuators and switches provide a reliable, cost-effective interface between the pneumatically-powered functions of applications and the electrical controls. They eliminate costly, time-consuming design and fabrication of independent electrical limit switch arrangements, and provide an aesthetically pleasing installation.

The switches perform the same function as conventional limit switches. They can be used as position indicators, cycle counters, or to confirm operation. They may also be used as safety devices by allowing for operation of secondary devices only when the actuator is properly positioned.

The Switch Application Selection Guide provides information on which type of switch is suitable for a particular applications.

All Bimba switches are designed to sense the magnet that is used in the MRS cylinder and in other Bimba actuators that are ordered with the -M option. All are normally open switches that close when sensing the magnet. Switch models differ by actuator product lines. Bimba also offers a variety of lead lengths and optional quick connect models. Refer to the Switch Application Selection Guide to determine which switch models are available for your actuator. Then check for information on those models for more information on options and specifications.

Benefits of the Magnetic Reed Switch

Compact
Lower cost
Easy to mount on a variety of Bimba actuators
Able to mount several switches on one actuator
LED available in many models for easy of positioning and troubleshooting
Many models:
- Low, medium and high current models, AC or DC, and triac-type switches for inductive kickback or inrush current.
- Track- and band-mounted models
- Choice of pigtail leads in 2 lengths or quick connect with two cable length options.

Benefits of the Hall Effect Switch

Compact
Solid state reliability — no moving parts means longer life, no contact bounce
Easy to mount on a variety of Bimba actuators
Able to mount several switches on one actuator
LED for ease of positioning and troubleshooting
Reverse polarity and overvoltage protection
Available with pigtail leads (in 2 lengths) or quick connect (with two cable length options)
Faster signal speeds

Benefits of the Low Profile Switch

Extremely small - the Bimba GMR Switches are the lowest profile switch currently available.
The Auto-Configure GMR Switch automatically determines whether the switch has been connected to a current sinking or sourcing load.
Solid state reliability - no moving parts means longer life, no contact bounce.
Fast response rate - 1 microsecond maximum.
Low, symmetrical hysteresis eases set-up and provides more accurate sensing.
Built-in fault protection including reverse polarity, overvoltage and transient protection.
LED verifies switching and eases set-up.
Several switches can be mounted on one actuator.
Pigtail leads in two lengths, with Quick Connect option for easy set-up.
For use with Bimba EF1, Twin Bore, and Original Line cylinders, and PneuMoment® actuators.

Switch Application Selection Guide
	Programmable Controllers	Relays	Solenoids	Indicator Lights		Motors	Time Counters
	Programmable Controllers	Relays	Solenoids	Bulbs	Solid State	Motors	Time Counters
Reed Switch	Yes	<5VA*	<5VA*	<5VA*	Yes	<5VA*	<5VA*
Triac Reed Switch**	No	Yes	Yes	Yes	No	Yes	Yes
Hall Effect Switch	Yes	<300mA	No	<300mA	Yes	No	<300mA
GMR Reed Switch	Yes	<5VA*	<5VA*	<5VA*	Yes	<5VA*	<5VA*
GMR Auto- configure Switch	Yes	Yes	No	No	Yes	No	Yes
GMR Source or Sink Output	Yes	<50mA	No	<50mA	Yes	No	<50mA

* Use resistor-capacitor protector **Minimum current = 100mA

Bimba Magnetic Reed Switch

This is a two-wire device with wires directly connected to a reed switch. Specifications are valid for purely resistive loads only. Choosing a switch is governed by Bimba's published load current derating curves. These are derived from the switch contact rating, expressed in wattage. Bimba offers magnetic reed switches that can handle the current requirements of a wide variety of applications. In addition, models are available for track- or band-mounting, and may include an LED indicator light to show when switching occurs.

A third wire is added for switches with LED indicator lights to power the LED.

Magnetic Reed/Triac-type Switch

This is a two-wire device recommended for high current AC loads. The reed switch senses the magnet and triggers the solid state triac that performs the actual current switching. The switch can handle up to 25A one-cycle surge to accommodate inductive kickback (current surge when an electrical device such as a solenoid coil is turned off) and inrush (current surge when a device is first turned on). Its operation is unreliable below 100mA load current. Maximum current is subject to ambient temperature. Models are available for track or band mounting.

How it works:

Reed switches contain hermetically-sealed reeds, or contacts. When the magnet on the piston moves close to the switch, the reeds become magnetized and the normally open contacts will close or pull in. The resulting signal can be used to signal or control operations in the system. When the magnet moves away from the piston, the contacts will open or drop out.

There are six distinct models of the MRS switch. Standard reed switches are two wire models and triac-type switches are three wire models. Contact ratings range from 3 watts to 10 watts maximum except for the MRS-1.5 models which range up to 1.5 amps maximum current.
MRS Switch Specifications and Options

Bimba Hall Effect Switch

This is a three-wire, solid state device recommended for low current DC loads such as interfacing with a programmable controller. It provides compact, reliable sensing for virtually infinite life. An LED indicator light illuminates when switching occurs. Models are available in current sinking (NPN) and current sourcing (PNP) models. Either can be used for loads such as counters and solid state relays. Selection of sinking or sourcing models depends on the requirements of the programmable controller.

How it works:

In operation, a constant current is passed through the Hall sensor. When the magnet is not directly below the sensor, the current (flow of electrons) is evenly distributed across the chip. With an equal number of electrons at the chip edges, no potential difference exists at the output. (V=0) When the magnet is directly below the sensor, the electron flow is distributed by the magnetic field to one side of the chip causing an imbalance in the electron concentration at the edges. This creates a potential difference, the Hall voltage, at the output. (V=V_HALL) This Hall voltage is detected and amplified to control a switching output transistor.

There are two distinct models of the Hall Effect switch. Both are three wire models. Input voltage is 5 to 30 VDC. The sinking model (HSK) has a 0.4 Volt drop maximum when energized. The sourcing model (HSC) has a 1.5 Volt drop maximum when energized. Both have a maximum 300 mA output current.
Hall Switch Specifications and Options

Bimba Low Profile Switch

Bimba's new low profile switches offer the latest giant magnetoresistive technology, and offers more features and functionality in the smallest package of any actuator position sensing switch. The switch fits in a track located on the cylinder's body and leaves it flush with the cylinder body. It has fast response, symmetrical hysteresis, and infinite life.

Bimba offers 4 different low profile switches:
Magnetic Reed Switch
GMR Auto-configure
GMR Source (PNP) output
GMR Sink (NPN) output.

How it works:

The Bimba GMR Switch is based on giant magnetoresistive (GMR) technology, which was first developed in 1988. It includes 4 GMR resistors (2 active, 2 shielded), each of which has many thin layers of magnetoresistive material. In each layer, the electrons are oriented opposite the adjacent layer, providing a great deal of resistance to electrical flow. The presence of a magnetic field overcomes the magnetic coupling between the adjacent layers, causing parallel alignment of magnetic moments between layers, and resistance drops significantly. By connecting the 4 resistors in a classic Wheatstone bridge configuration, the voltage across a single resistor is doubled, providing a linear output. This voltage is then amplified, and sent to a comparator that switches the sensor output when it detects that a minimum magnetic field strength is present. High voltage transistors provide TTL-compatible output rated at 25 milliamps. The switch includes reverse polarity, overvoltage and transient protection.

There are four distinct models of the Low Profile switch. The MR (magnetic reed) model is a two wire model and the others are three wire models. Input voltage is 5 to 24 VDC for the MS models and 3 to 120 VAC or 3 to 24 VDC for the MR model. The sinking models (MS or MSK) has a 0.4 Volt drop maximum when energized. The sourcing model (MS or MSC) has a 1.5 Volt drop maximum when energized.
Low Profile Switch Specifications and Options

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