Implementing 3-Switch XOR Ladder Logic with Internal Bit
Implement a 3-SPST switch XOR light circuit in LogixPro or RSLogix 500 using an internal relay bit. Includes truth tables, boolean equations, and verified.
The BECKHOFF C9900-E778 is a push-button extension designed for CP6x32-00xx and CP7x32-00xx Control Panels and Panel PCs. It is installed on the right side of compatible operator-panel configurations.
The extension provides 18 Siemens Signum square push-button keys with integrated signal lamps. Each push-button measures 30 x 30 mm. Labels can be inserted into the push-button caps for individual machine-function identification.
Each push-button provides one normally-open contact transmitted through CP-Link or USB. A second normally-open contact is available for direct wiring through a terminal row. The integrated signal lamps are controlled through CP-Link or USB only.
The assembly also includes one directly wireable Siemens Signum emergency stop key. This combination supports operator commands, status indication, and directly wired control functions from the same panel-side extension.
Push-button extension for CP6x32-00xx and CP7x32-00xx devices
Right-side mounting arrangement
18 Siemens Signum square push-button keys
30 x 30 mm push-button format
Integrated signal lamp for each push-button
Individual labeling through replaceable push-button cap labels
One normally-open contact transmitted through CP-Link or USB
Second normally-open contact available through a terminal row
Signal lamp communication through CP-Link or USB
One directly wireable Siemens Signum emergency stop key
Machine operator stations using CP6xxx or CP7xxx panels
Physical machine command functions alongside panel operation
Local status indication through illuminated push-buttons
Operator interfaces requiring individually labeled control keys
Applications combining digital button transmission with direct-wired contacts
Machine control stations requiring an emergency stop device
| Parameter | Specification |
|---|---|
| Manufacturer | BECKHOFF |
| Part Number | C9900-E778 |
| Product Type | Push-button extension |
| Compatible Models | CP6x32-00xx and CP7x32-00xx |
| Installation Position | Right side |
| Product Status | Service phase |
| Parameter | Specification |
|---|---|
| Push-button Quantity | 18 |
| Push-button Type | Siemens Signum square |
| Push-button Size | 30 x 30 mm |
| Signal Lamps | Integrated |
| Labeling | Individual marking through push-button cap labels |
| Emergency Stop | 1 Siemens Signum emergency stop key |
| Emergency Stop Connection | Directly wireable |
| Parameter | Specification |
|---|---|
| Primary Push-button Contact | 1 normally-open contact per push-button |
| Primary Signal Transmission | CP-Link or USB |
| Secondary Push-button Contact | Second normally-open contact |
| Secondary Contact Connection | Direct wiring through terminal row |
| Signal Lamp Transmission | CP-Link or USB only |
| Interface | Function |
|---|---|
| CP-Link | Transmission of push-button states and signal lamp control |
| USB | Transmission of push-button states and signal lamp control |
| Terminal row | Direct wiring of the second normally-open contact for each push-button |
| Direct wiring | Emergency stop connection |
Confirm that the target panel is a CP6x32-00xx or CP7x32-00xx configuration.
Verify that the right-side mounting arrangement matches the required operator-station design.
Inspect the push-button extension, terminal row, and connection interfaces before installation.
Mount the extension according to the applicable Beckhoff panel installation documentation.
Connect CP-Link or USB according to the selected system architecture.
Wire secondary normally-open contacts where direct machine signals are required.
Integrate the emergency stop according to the approved machine safety circuit.
Apply clear labels to identify each machine-control function.
Test push-buttons, signal lamps, direct contacts, and emergency stop operation before commissioning.
Verify each push-button individually through the selected CP-Link or USB interface.
Where secondary normally-open contacts are used, test the directly wired circuits independently at the terminal row.
Check all signal lamps through the connected control system and confirm that each indication corresponds to the assigned machine function.
Validate the emergency stop circuit independently before releasing the machine for normal operation.
Confirm the complete part number C9900-E778 before replacing an existing push-button extension.
Verify compatibility with the exact CP6x32-00xx or CP7x32-00xx panel configuration before procurement.
Record existing push-button labels and wiring assignments before removing the installed extension. This helps preserve operator functions during replacement.
Because the product is in service phase, confirm current availability and replacement planning before scheduling maintenance.
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Returns & Warranty

The BECKHOFF C9900-E778 is a push-button extension designed for CP6x32-00xx and CP7x32-00xx Control Panels and Panel PCs. It is installed on the right side of compatible operator-panel configurations.
The extension provides 18 Siemens Signum square push-button keys with integrated signal lamps. Each push-button measures 30 x 30 mm. Labels can be inserted into the push-button caps for individual machine-function identification.
Each push-button provides one normally-open contact transmitted through CP-Link or USB. A second normally-open contact is available for direct wiring through a terminal row. The integrated signal lamps are controlled through CP-Link or USB only.
The assembly also includes one directly wireable Siemens Signum emergency stop key. This combination supports operator commands, status indication, and directly wired control functions from the same panel-side extension.
Push-button extension for CP6x32-00xx and CP7x32-00xx devices
Right-side mounting arrangement
18 Siemens Signum square push-button keys
30 x 30 mm push-button format
Integrated signal lamp for each push-button
Individual labeling through replaceable push-button cap labels
One normally-open contact transmitted through CP-Link or USB
Second normally-open contact available through a terminal row
Signal lamp communication through CP-Link or USB
One directly wireable Siemens Signum emergency stop key
Machine operator stations using CP6xxx or CP7xxx panels
Physical machine command functions alongside panel operation
Local status indication through illuminated push-buttons
Operator interfaces requiring individually labeled control keys
Applications combining digital button transmission with direct-wired contacts
Machine control stations requiring an emergency stop device
| Parameter | Specification |
|---|---|
| Manufacturer | BECKHOFF |
| Part Number | C9900-E778 |
| Product Type | Push-button extension |
| Compatible Models | CP6x32-00xx and CP7x32-00xx |
| Installation Position | Right side |
| Product Status | Service phase |
| Parameter | Specification |
|---|---|
| Push-button Quantity | 18 |
| Push-button Type | Siemens Signum square |
| Push-button Size | 30 x 30 mm |
| Signal Lamps | Integrated |
| Labeling | Individual marking through push-button cap labels |
| Emergency Stop | 1 Siemens Signum emergency stop key |
| Emergency Stop Connection | Directly wireable |
| Parameter | Specification |
|---|---|
| Primary Push-button Contact | 1 normally-open contact per push-button |
| Primary Signal Transmission | CP-Link or USB |
| Secondary Push-button Contact | Second normally-open contact |
| Secondary Contact Connection | Direct wiring through terminal row |
| Signal Lamp Transmission | CP-Link or USB only |
| Interface | Function |
|---|---|
| CP-Link | Transmission of push-button states and signal lamp control |
| USB | Transmission of push-button states and signal lamp control |
| Terminal row | Direct wiring of the second normally-open contact for each push-button |
| Direct wiring | Emergency stop connection |
Confirm that the target panel is a CP6x32-00xx or CP7x32-00xx configuration.
Verify that the right-side mounting arrangement matches the required operator-station design.
Inspect the push-button extension, terminal row, and connection interfaces before installation.
Mount the extension according to the applicable Beckhoff panel installation documentation.
Connect CP-Link or USB according to the selected system architecture.
Wire secondary normally-open contacts where direct machine signals are required.
Integrate the emergency stop according to the approved machine safety circuit.
Apply clear labels to identify each machine-control function.
Test push-buttons, signal lamps, direct contacts, and emergency stop operation before commissioning.
Verify each push-button individually through the selected CP-Link or USB interface.
Where secondary normally-open contacts are used, test the directly wired circuits independently at the terminal row.
Check all signal lamps through the connected control system and confirm that each indication corresponds to the assigned machine function.
Validate the emergency stop circuit independently before releasing the machine for normal operation.
Confirm the complete part number C9900-E778 before replacing an existing push-button extension.
Verify compatibility with the exact CP6x32-00xx or CP7x32-00xx panel configuration before procurement.
Record existing push-button labels and wiring assignments before removing the installed extension. This helps preserve operator functions during replacement.
Because the product is in service phase, confirm current availability and replacement planning before scheduling maintenance.
Global Express Shipping
Returns & Warranty
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For full eligibility, restocking fees, and international return details, please view our official Refund & Return Policy .
| Color pattern |
Greyish White
|
| Country of origin |
Germany
|