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OMRON Releases Machine Safeguarding Units

June 6, 2008

Standstill and Low-speed Monitoring Units Ensure Safety while Improving Productivity

KYOTO, Japan - OMRON Corporation (TOKYO: 6645, ADR: OMRNY) has announced the release of new products, the G9SX-SM standstill monitoring unit and G9SX-LM low-speed monitoring unit, to markets.

The G9SX-SM and G9SX-LM encourage operator safety by monitoring the speed of a machine's rotating parts to determine when it is safe for operators to enter protected areas.

The basic principle for operator safety is the physical separation of operators and machines. This is typically achieved by installing safety features such as a protective fence around hazard sources. However, even when a hazard stops operating in this type of system, the operator cannot immediately enter the area inside the fence, making it difficult to perform maintenance and other irregular operations. These drawbacks have caused problems in operator productivity.

The G9SX-SM and G9SX-LM directly determine the operating condition of a machine by monitoring the speed of rotating parts. The G9SX-SM monitors the back electromotive force (BEMF) of a machine's motor to judge whether the machine has stopped operating, and the G9SX-LM uses a proximity sensor to monitor standstill and speed conditions. The units are effective in the following situations.

G9SX-SM Standstill Monitoring Unit

Conventionally, in order to load or unload a workpiece in a machine with long inertia operation, the time required for the operation to stop is predicted, and an off-delay timer is set to unlock the Guard Lock Safety Door Switch after the operation has stopped. However, because the time until the machine stops operating is subject to change with various operating conditions, this system results in extra wait time.

The G9SX-SM monitors the motor's movement by its back electromotive force (BEMF), and outputs a signal to unlock the Guard Lock Safety Door Switch as soon as it determines that the motor has stopped moving. This allows the operator to smoothly load or unload a workpiece while being assured of safety and maintaining productivity.

G9SX-LM Low-speed Monitoring Unit

Operators sometimes have to work in the vicinity of a hazard during irregular operations, such as maintenance and adjustments, and it is necessary to operate the machine for work efficiency. Until now, this has been a problem on many production lines because no clear solution has existed for ensuring both safety and productivity.

The G9SX-LM combines with OMRON's E2E proximity sensors to directly sense the operation of a hazard and monitor its speed of rotation. The G9SX-LM is also equipped with an input terminal for an enabling grip switch, and can monitor whether the switch is being pressed. It allows the machine to operate with the door of the protective fence open only when the rotational speed of the hazard source is below a pre-set threshold and the operator is pressing the enabling grip switch. In this way, the G9SX-LM is able to ensure both safety and productivity during irregular operations.

Main Features

1. Standstill monitored by the motor's BEMF signal

There is no need to install a sensor to monitor operation because the voltage between motor phases is directly input into the G9SX-SM.

2. Standard configuration eliminates need for user settings

With standard configuration, there is no need to set the threshold for monitoring the rotation standstill, so operation can start immediately by connecting the G9SX-SM to the machine. If settings are required to match the characteristics of the machine, user configuration makes it possible to manually adjust the threshold.

3. Detailed LED indications

The G9SX-SM also includes the LED indications that are a feature of the entire G9SX series, to simplify fault diagnosis.

4. Compliant with safety standards

The G9SX-SM has obtained certification for Safety Category 4 (EN954-1)and SIL3 (IEC/EN62061). This high level of safety allows use with a wide variety of machines.

1. Direct rotational speed monitoring with proximity sensors

The G9SX-LM uses proximity sensors to directly monitor the rotational speed of a hazard source. It monitors whether the hazard source is rotating at a speed that is below the threshold that was set for the machine.

2. Enabling switch input for maintenance work

The machine can be operated for maintenance only if the hazard source is rotating at a speed that is below the set threshold and the operator is pressing the enabling grip switch.

3. Normal operating mode and maintenance mode

The operator chooses the mode with a selector switch. Normal operating mode turns on the standstill monitoring function, and maintenance mode turns on the low-speed monitoring function.

4. Compliant with safety standards

The G9SX-LM has obtained certification for Safety Category 3 (EN954-1)and SIL3 (IEC/EN62061). This high level of safety allows use with a wide variety of machines.


OMRON Takeo Co., Ltd.

Main Specifications

Safety inputs None
Safety standstill detection outputs 3
Auxiliary outputs 2
Dimensions (mm) 100 x 35 x 115 (HxWxD)
Safety inputs 1 series (2-channel input)
Enabling inputs 1 series (2-channel input)
Safety instantaneous outputs 2
Safety low-speed/standstill monitoring outputs 2
Auxiliary outputs 4
Low-speed threshold 2 to 10 Hz
Dimensions (mm) 100 x 45 x 115 (HxWxD)

Sales Target

3,000 units in the first year


Headquartered in Kyoto, Japan, OMRON Corporation is a global leader in the field of automation. Established in 1933 and headed by President & CEO Hisao Sakuta, OMRON has over 35,000 employees in 38 countries working to provide products and services to customers in a variety of fields, including industrial automation, electronic components, social systems (ticket gate machines, ticket vending machines and traffic control) and healthcare. For more information, visit OMRON's website at www.omron.comicon_07.


Product Inquiries
Hideo Tashiro (
OMRON IA Safety Devices Division
Tel.: +81-75-344-7093

Media Inquiries
Osamu Harasawa (
OMRON IA Strategy Planning Division
Tel.: +81-3-3779-9434