Siemens 6AV6355-1AA47-7DM1 OP 77A

SKU: 6AV6355-1AA47-7DM1 Category: HMI & Display Brand: Siemens

Description
Additional information

The Siemens 6AV6355-1AA47-7DM1 is an operator panel belonging to the SIMATIC HMI OP 77A series, manufactured by Siemens. It is a compact, key-operated panel designed for machine-level human-machine interface applications, providing operators with a straightforward means of monitoring and controlling automation processes. This unit is part of the SIMATIC HMI Basic Panels generation, intended for use with Siemens SIMATIC S7 PLCs and compatible controllers.

The OP 77A features a monochrome LCD display with a resolution of 160 x 80 pixels, offering clear text and simple graphic visualization. It supports MPI and PROFIBUS DP communication interfaces, enabling direct integration into Siemens automation networks. The panel is configured using WinCC flexible software and provides function keys for operator input, with LED indicators for status feedback. The unit operates on a 24 V DC supply and is rated to IP65 on the front face, making it suitable for panel-mount installations in industrial enclosures.

The OP 77A is commonly deployed in manufacturing, process automation, and machine tool environments where a cost-effective, robust operator interface is required. It is well suited for applications such as conveyor systems, packaging machinery, and general-purpose machine control where simple text-based status display and operator input are sufficient. Its compact form factor and compatibility with the SIMATIC ecosystem make it a practical choice for retrofitting or extending existing Siemens-based control systems.

Technical Specifications

Display Type	Monochrome LCD
Display Resolution	160 x 80 pixels
Input Voltage	24 V DC
Communication Interface	MPI, PROFIBUS DP
IP Rating (Front)	IP65
IP Rating (Rear)	IP20
Operating Temperature	0 °C to +50 °C
Storage Temperature	-20 °C to +60 °C
Relative Humidity	10% to 90% (non-condensing)
Mounting	Panel mount
Configuration Software	WinCC flexible
Certifications	CE, UL
Series	SIMATIC HMI OP 77A

Common Error Codes & System Events

Event ID: 10000: Connection to PLC lost or communication timeout on MPI/PROFIBUS interface.
Check MPI/PROFIBUS cable connections and termination resistors. Verify PLC is powered and in RUN mode. Check configured station address matches the PLC.
Event ID: 10001: No connection to configured PLC at startup.
Verify communication parameters (baud rate, station address) in WinCC flexible project. Ensure the PLC is online and the network is properly terminated.
Event ID: 20000: Project download failed or project data corrupted.
Re-download the WinCC flexible project to the panel. Check USB or serial transfer cable and retry. If persistent, perform a factory reset and re-download.
Event ID: 40000: Internal device error or hardware fault detected.
Cycle power to the panel. If the fault persists, note the full event ID and contact Siemens technical support or arrange for unit repair.
Event ID: 50000: Configured tag or variable not found in PLC data block.
Verify that the PLC program contains the data blocks and tags referenced in the HMI project. Re-download the HMI project after correcting tag addresses.
Event ID: 70000: Illegal parameter value written to a tag.
Check the configured limit values for the affected tag in WinCC flexible. Ensure operator input is within the defined range and data type is correct.

Frequently Asked Questions

What communication interfaces does the OP 77A support?

The OP 77A supports MPI and PROFIBUS DP interfaces, allowing direct connection to Siemens SIMATIC S7-200, S7-300, and S7-400 PLCs.

What software is used to configure the 6AV6355-1AA47-7DM1?

The panel is configured using Siemens WinCC flexible software. The project is then transferred to the panel via a serial or USB-to-serial connection.

What is the supply voltage for this operator panel?

The OP 77A operates on a 24 V DC supply voltage, typically sourced from a standard industrial power supply unit.

What is the front panel protection rating?

The front face of the OP 77A is rated to IP65, providing protection against dust ingress and low-pressure water jets, making it suitable for panel-mount use in industrial environments.

Can this panel be used as a replacement for older Siemens OP panels?

The OP 77A is designed as a successor to earlier SIMATIC OP panels such as the OP7 and OP17, and can often serve as a drop-in replacement with appropriate project migration in WinCC flexible.

Troubleshooting

Display remains blank after power is applied

Measure the 24 V DC supply voltage at the panel's power connector. Check that polarity is correct and voltage is within the specified range.

Correct any wiring errors or supply voltage issues. If the supply is confirmed good and the display remains blank, the internal power supply or display backlight may have failed and the unit should be sent for repair.

Panel displays 'No connection to PLC' or communication error at startup

Check the MPI or PROFIBUS DP cable for continuity and correct termination at both ends of the network. Verify the station address configured in the HMI project matches the PLC address.

Replace or reseat the communication cable. Correct the station address and baud rate settings in the WinCC flexible project and re-download. Ensure bus termination resistors are enabled only at the two physical ends of the network.

Function keys do not respond to operator input

Test each function key individually in the panel's built-in test mode if available. Inspect the keypad membrane for physical damage or contamination.

Clean the keypad area. If keys remain unresponsive, the keypad membrane or internal PCB may be faulty and the unit should be inspected and repaired by a qualified technician.

Project download fails or transfer is interrupted

Check the serial or USB-to-serial transfer cable and the COM port settings on the engineering PC. Ensure WinCC flexible is set to the correct transfer mode and baud rate.

Replace the transfer cable if faulty. Set the panel to transfer mode manually via the panel's start center menu. Retry the download. If the issue persists, perform a factory reset on the panel before re-downloading.

Panel reboots repeatedly or enters a boot loop

Check the 24 V DC supply for voltage drops or ripple under load. Inspect the panel for signs of overheating or environmental contamination.

Stabilize the power supply and ensure adequate current capacity. Allow the panel to cool if overheating is suspected. If the boot loop continues with a stable supply, the internal firmware or flash memory may be corrupted and the unit requires professional repair.

Condition	Repair, Used, Refurbished, New in box (sealed)