BECKHOFF C9900-E789 Push-button extension for CP6xxx and CP7xxx Control Panels and Panel PCs

The BECKHOFF C9900-E789 is a push-button extension designed for integration below CP6942, CP7942 Control Panels and CP6242, CP6442, CP6542, and CP7242 Panel PCs featuring 15-inch displays without keyboards. It serves as a physical operator interface for machine tools, routing discrete actuation and state indication signals via USB and direct-wire terminal connections.

Technical Summary

This control panel extension provides a localized physical interface for machine control applications. It integrates discrete inputs and outputs through a dual-channel architecture: a USB interface handles serial data transmission for primary push-button state reporting and exclusive control of the indicator lights, while independent terminal rows allow parallel, hardwired connection for critical control loops. An integrated Gray code switch provides absolute position encoding over USB, and a front-accessible dual-port USB hub extends backplane connectivity for external peripherals.

Hardware Specifications

Engineering Notes

• Signal Logic: The 16 standard push-buttons feature split-circuit routing. The first normally-open (NO) contact maps to the internal USB controller for cyclic data exchange with the host PC. The second NO contact is mechanically isolated and routed directly to the terminal block for traditional 24 VDC I/O routing to a PLC backplane.
• Indicator Control: The integrated signal lamps within the 16 push-buttons do not possess local hardwired inputs. Their activation states are driven exclusively via downstream USB command strings from the host controller.
• Safety Circuits: The emergency stop switch bypasses the internal USB bus entirely. It must be integrated into the local safety relay or safety PLC circuit using the direct-wire terminals to meet machine safety standards.
• Gray Code Switch: The 23-position rotary switch utilizes gray code formatting to prevent ambiguous bit transitions during rotation, transmitting the absolute position data directly over the USB interface.

Field Guidelines

• EMC Separation & Shielding: To prevent signal corruption on the USB bus, route the internal USB uplink cable away from high-voltage AC motor leads and variable frequency drive (VFD) output cables. Ensure the control panel housing achieves low-impedance grounding to the machine chassis.
• Terminal Wiring: When wiring the secondary NO contacts to the terminal row, use fine-stranded copper conductors with insulated ferrules. Observe standard torque ratings on the screw terminals to prevent contact damage.
• Ingress Protection: The front-accessible 2-port USB A interface achieves its IP65 rating only when the protective screw cap is fully engaged and tightened against the gasket. Ensure the cap is secured whenever the front ports are not actively servicing external equipment.

The BECKHOFF C9900-E789 is a push-button extension designed for integration below CP6942, CP7942 Control Panels and CP6242, CP6442, CP6542, and CP7242 Panel PCs featuring 15-inch displays without keyboards. It serves as a physical operator interface for machine tools, routing discrete actuation and state indication signals via USB and direct-wire terminal connections.

Technical Summary

This control panel extension provides a localized physical interface for machine control applications. It integrates discrete inputs and outputs through a dual-channel architecture: a USB interface handles serial data transmission for primary push-button state reporting and exclusive control of the indicator lights, while independent terminal rows allow parallel, hardwired connection for critical control loops. An integrated Gray code switch provides absolute position encoding over USB, and a front-accessible dual-port USB hub extends backplane connectivity for external peripherals.

Hardware Specifications

Engineering Notes

• Signal Logic: The 16 standard push-buttons feature split-circuit routing. The first normally-open (NO) contact maps to the internal USB controller for cyclic data exchange with the host PC. The second NO contact is mechanically isolated and routed directly to the terminal block for traditional 24 VDC I/O routing to a PLC backplane.
• Indicator Control: The integrated signal lamps within the 16 push-buttons do not possess local hardwired inputs. Their activation states are driven exclusively via downstream USB command strings from the host controller.
• Safety Circuits: The emergency stop switch bypasses the internal USB bus entirely. It must be integrated into the local safety relay or safety PLC circuit using the direct-wire terminals to meet machine safety standards.
• Gray Code Switch: The 23-position rotary switch utilizes gray code formatting to prevent ambiguous bit transitions during rotation, transmitting the absolute position data directly over the USB interface.

Field Guidelines

• EMC Separation & Shielding: To prevent signal corruption on the USB bus, route the internal USB uplink cable away from high-voltage AC motor leads and variable frequency drive (VFD) output cables. Ensure the control panel housing achieves low-impedance grounding to the machine chassis.
• Terminal Wiring: When wiring the secondary NO contacts to the terminal row, use fine-stranded copper conductors with insulated ferrules. Observe standard torque ratings on the screw terminals to prevent contact damage.
• Ingress Protection: The front-accessible 2-port USB A interface achieves its IP65 rating only when the protective screw cap is fully engaged and tightened against the gasket. Ensure the cap is secured whenever the front ports are not actively servicing external equipment.

Suffix Breakdown

• CP6xxx / CP7xxx Compatibility: Form-factor and mounting brackets are mechanically optimized specifically for 15-inch display variants within these series that lack integrated physical keyboards.
• Service Phase: This unit is designated for maintenance, legacy system expansion, and direct field replacement within existing automation lines.