Catalogs > Safety Products Catalog > Power > Safety Isolation System
Safety Isolation System
| Introduction |  |
Specifications | |
Sequence of Operation | |
Communication | |
Product Selection | |
Introduction | |
| Optional Expansion Module | |
Remote Lockout Station | |
Verification Module | |
Multiplexer/Permissive Module | |
System Selection Process | |
When multiple energy sources must be controlled simultaneously or the system must be stopped at a pre-determined stopping point, the LOTO process becomes more complicated with multi-step procedures and locks. The Hydraulic/Pneumatic Multiplexer and the system Multiplexer/Permissive Module were developed to help provide simultaneous control of multiple hazards from a single lockout point.
Coordination between the process or drive system control and the LOTO process, is a concern. In a typical system, a signal from the LOTO device is sent to the control system. This provides indication that the device has been switched to the OFF position. This requires the person switching the device to ensure the process or machine has stopped. Ideally this would be coordinated so the power is not disconnected until the process or drive system is at an acceptable stopping point. The addition of the Permissive function to the System Multiplexer allows the control system to signal the ElectroGuard system when it is at the desired stopping point. This function would only allow the stopping function (i.e., the control system can not restore power). That function can only be accomplished via the RLSs attached to the System Multiplexer/Permissive Module.
The diagram below depicts a system with multiple motors or drives that require a synchronized lockout. This system also requires that the power to the drives must be maintained during certain phases of the process. The control system is interfaced with the ElectroGuard systems via the Permissive option in the System Multiplexer/Permissive Module. This allows the control system to delay disconnecting power until the drives are at an allowable point in the process.
Functional Description
The System Multiplexer Module allows a Remote Lockout Station (RLS) to control up to four ElectroGuard systems simultaneously. The System Multiplexer Module will accept up to six RLS inputs. If there is a need to control more than four ElectroGuard systems, the System Multiplexer Modules can be daisy-chained as shown in the drawing below. For applications where more than four RLSs are required, an expansion module may be used.
The System Multiplexer Module is also available with a Permissive option. The Permissive option allows the machine controlling the process or drive system to bring the machine or process to a pre-determined stopping point prior to removal of power by the ElectroGuard system. Once the ElectroGuard system isolates the energy, the machine control can not re-energize the ElectroGuard.
Sequence of Events for System Multiplexer Module:
| 1. | When a RLS is turned OFF, the outputs of the System Multiplexer Module are switched to the off or open state, see diagram below. |
| 2. | This signal is connected to the input of the ElectroGuard systems initiating the isolation process. |
| 3. | When all of the ElectroGuard systems are in the isolated state the System Multiplexer Module sends the Isolated signal to the RLS and the RLS System Isolated pilot light will be illuminated. |
Sequence of Events for System Multiplexer Module with Permissive Option:
| 1. | A PLC output is connected to the System Multiplexer/Permissive Module. This signal is used by the System Multiplexer/Permissive Module as a heart beat. This holds the output of the System Multiplexer/Permissive Module in the on or closed state, holding the ElectroGuard system in the on or non-isolated state. |
| 2. | When a RLS is turned OFF, a signal is transmitted to the control system via a PLC connection on the RLS auxiliary contacts, see diagram below. Note that the outputs of the System Multiplexer/Permissive Module remain in the on or closed state. |
| 3. | When the customer’s control system is at a predetermined stopping point, the control system, via the PLC output, is turned to an off state (no heart beat) and the outputs of the System Multiplexer/Permissive Module are then switched to the off or open state. |
| 4. | The system isolation function is then initiated on all of the ElectroGuard systems simultaneously. |
| 5. | When all of the ElectroGuard systems are in the isolated state, the System Multiplexer/Permissive Module sends the Isolated signal to the RLS and the RLS System Isolated pilot light on the RLS will be illuminated. The RLS now has control of the ElectroGuard and the energy can only be restored to the machine or process by switching all of the RLSs connected to the multiplexers to the on state. |
| NOTE: Modification to the logic in the customer’s control system is required if the Permissive option is used. See user manual for details. |
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| Multiple Energy Sources |
Bulletin 2030 Multiplexer/Permissive Module
| 2030-MLX | — | J | F | SYS | ||
| a | b | c |
| a | |
| Enclosure Type | |
| Code | Description |
| C | Type 4X watertight stainless steel |
| F | Type 4 watertight painted steel/IP65 |
| J | Type 12 dusttight/IP54 |
| N | Open |
| M | Open Type installed in ElectroGuard¬ |
¬ Can be installed in most 110…1200 A systems
| b | |
| Number of Systems to Control | |
| Code | Description |
| F | 4 systems |
| c | |
| System Type | |
| Code | Description |
| SYS | EG system |
| SYSP | EG system with permissive option |
| HPM | Hydraulic/pneumatic module |