How Monitoring Can Boost E-Stop Reliability
A functioning Emergency Stop button on machinery is crucial for the protection of people and equipment in the workplace. It ensures that in an emergency situation, machinery can be quickly shut down to prevent injury or equipment damage.
There are numerous scenarios when employees may need to activate a machine’s E-Stop switch. This includes entanglement (e.g. where a person’s clothing or body parts are pulled into contact with a machine’s moving parts) or where a machine is malfunctioning or behaving abnormally.
Schneider Electric’s Harmony XB4 and XB5 ‘self-monitoring’ contact blocks help improve the reliability of E-Stops on machinery.
Here’s how.
What can go wrong with E-Stops?
E-Stops can become damaged, detached, broken or worn over time. It could spell disaster if an employee pushes the button in an emergency situation, and nothing happens!
Problems can also happen with a switch’s attached contact block – the device that controls the flow of electricity and ensures the switch does what it is designed to do.
When an E-Stop contact block is correctly installed, the ‘normally closed’ contacts are opened when the switch is pressed, in turn cutting off power to the machine.
However, a contact block might become detached due to stripped attachment screws, excessive vibration, not being reinstalled after maintenance, or for some other reason. When this happens, the attached E-Stop will fail to activate when pressed.
How Schneider’s Harmony Monitoring Contacts Work
The Harmony XB4/XB5 contact blocks essentially monitor the status of their own installation.
This means if the E-Stop is damaged or missing, or the contact block becomes separated from the switch, the circuit will open and force the machine or process to automatically shut down.
This in turn can help improve safety for employees by reducing the risk of machine entanglements. It also lowers the risk of damage to machinery, equipment and products, and alerts staff to E-Stop repair and maintenance issues.
Features and benefits of the XB4/XB5 contact blocks include:
- Slow-break contact operation.
- High resistance to vibration due to shake-proof terminal screws.
- NC positive opening contact blocks are compatible with safety applications.
- Easy to use in the same place as existing ZBE 102 NC contacts.
- Compatible with all Schneider XB4 and XB5 Emergency Stops (except specific reference ZB5AT8643M).
- Can be installed upfront or retrofitted.
- Potential cost savings due to reduced accidents and machinery damage, and more timely repairs and maintenance.
Contact blocks for a range of applications
The Harmony monitoring contact block suits a range of industrial situations involving the use of heavy machinery. This includes agriculture (e.g. for wool presses and dryers), plastics, food processing, mining, construction, government infrastructure, demolition and waste management.
Monitoring contacts also act as a valuable precaution in robot cells, and can be especially useful on the plant floor, where there is moving machinery nearby (such as forklifts) that could potentially bump into, dislodge or break an E-Stop button.
The Harmony monitoring E-Stop contact block can enhance the security of your machinery and the safety of your workplace. Order the XB4 or XB5 E-Stop models at Blackwoods online, or visit your local branch.
