Siemens 6AV6355-1AA47-7EQ2 OP 77A

SKU: 6AV6355-1AA47-7EQ2 Category: HMI & Display Brand: Siemens

Description
Additional information

The Siemens 6AV6355-1AA47-7EQ2 is an operator panel belonging to the SIMATIC HMI OP 77A series, designed for machine-level human-machine interface applications. It is a compact, key-operated panel that provides a straightforward interface for monitoring and controlling industrial processes. This unit is part of Siemens' SIMATIC HMI product line, which is widely deployed across automation environments requiring reliable operator interaction.

The OP 77A features a monochrome LCD display and a membrane keypad with function keys, system keys, and numeric entry capability, allowing operators to navigate screens and enter process values without a touchscreen. It supports MPI and PROFIBUS DP communication interfaces for direct integration with SIMATIC S7 PLCs, and can also communicate via PPI with S7-200 controllers. The panel operates on a 24 V DC supply and is designed for panel front mounting with an IP65 protection rating on the front face, making it suitable for use in environments where dust and water ingress are a concern.

The OP 77A is commonly used in manufacturing machinery, conveyor systems, packaging equipment, and process plants where a cost-effective, robust operator terminal is required. Its compatibility with the SIMATIC S7-200, S7-300, and S7-400 controller families makes it a versatile choice for both new installations and retrofit projects. The panel is particularly well suited to applications where a compact footprint and simple navigation are priorities over graphical richness.

Technical Specifications

Display Type	Monochrome LCD
Display Size	4 lines x 20 characters
Keypad Type	Membrane keypad with function keys and numeric keys
Input Voltage	24 V DC
Voltage Tolerance	19.2 V DC to 28.8 V DC
Power Consumption	Max. 4.5 W
Communication Interface	MPI, PROFIBUS DP, PPI
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 front mounting
Certifications	CE, UL, cULus

Common Error Codes and System Events

Event ID: 10000: Communication error between the OP 77A and the connected PLC. The panel cannot establish or maintain a connection to the controller.
Check MPI or PROFIBUS DP cable connections and termination resistors. Verify the PLC address settings match the configuration in WinCC flexible. Ensure the PLC is powered and in RUN mode.
Event ID: 10001: Connection to the PLC has been interrupted during operation.
Inspect the communication cable for damage or loose connectors. Check bus termination and cable shielding. Restart the panel and PLC if the connection is not restored automatically.
Event ID: 20000: Project download error. The project could not be transferred to the panel successfully.
Verify the transfer cable and PC interface settings. Ensure the panel is in transfer mode before initiating the download from WinCC flexible. Check available memory on the panel.
Event ID: 40000: System memory low. The panel is running low on available runtime memory.
Reduce the number of active alarms or logged data entries. Optimize the project to reduce memory usage and re-download the project to the panel.
Event ID: 50000: Configuration error detected. The loaded project contains settings incompatible with the panel hardware or firmware version.
Verify the project was compiled for the correct panel type and firmware version in WinCC flexible. Re-download a compatible project to the panel.
Event ID: 60000: Firmware update error. The firmware update process was interrupted or failed.
Retry the firmware update using the correct firmware package for the OP 77A. Ensure stable power supply during the update process and use the correct ProSave or WinCC flexible tool.

Frequently Asked Questions

Which PLCs are compatible with the OP 77A?

The OP 77A is compatible with SIMATIC S7-200 (via PPI), S7-300, and S7-400 (via MPI or PROFIBUS DP). It can also communicate with SIMATIC S5 controllers via suitable adapters.

What software is used to configure the OP 77A?

The OP 77A is configured using Siemens WinCC flexible software. Projects are created on a PC and downloaded to the panel via a PC/MPI adapter or PROFIBUS connection.

What is the supply voltage for the 6AV6355-1AA47-7EQ2?

The panel requires a 24 V DC supply with an allowable range of 19.2 V DC to 28.8 V DC.

Does the OP 77A support touchscreen operation?

No, the OP 77A uses a membrane keypad for operator input. It does not have a touchscreen; navigation is performed using function keys and system keys.

What is the front panel protection rating of the OP 77A?

The front face of the OP 77A carries an IP65 protection rating, making it resistant to dust ingress and low-pressure water jets when correctly installed in a panel cutout.

Troubleshooting

Display remains blank after power on

Check the 24 V DC supply voltage at the panel power connector. Verify the voltage is within the 19.2 V to 28.8 V range. Inspect the supply cable and connector for damage.

Restore the correct supply voltage. If the supply is confirmed correct and the display remains blank, the internal power supply or display backlight may have failed and the unit should be sent for repair or replacement.

Panel shows 'No connection to PLC' or communication error on startup

Verify the MPI or PROFIBUS DP address configured in the project matches the physical PLC address. Check the communication cable for continuity and correct pin assignment. Confirm bus termination resistors are correctly placed at both ends of the bus.

Correct any address mismatches in the WinCC flexible project and re-download. Replace damaged cables and ensure proper bus termination. If using PROFIBUS, verify the baud rate settings match across all devices on the bus.

Project download fails or transfer cannot be initiated

Confirm the panel is set to transfer mode before starting the download. Check the PC interface adapter (PC/MPI or USB/MPI) is correctly installed and the COM port or USB settings in WinCC flexible match the adapter configuration.

Place the panel in transfer mode via the start screen. Reinstall or reconfigure the PC adapter driver. Attempt the transfer again with the correct interface settings selected in WinCC flexible.

Function keys do not respond or produce incorrect actions

Check whether the correct project is loaded on the panel. Inspect the membrane keypad for physical damage or contamination beneath the keys. Verify the key assignments in the WinCC flexible project.

Re-download the correct project to the panel. If the keypad is physically damaged or keys are stuck due to contamination, the membrane keypad assembly should be replaced.

Panel restarts repeatedly or enters a boot loop

This may indicate a corrupted project file or a firmware issue. Check whether the panel completes the boot sequence before restarting. Attempt to enter transfer mode during startup to bypass the loaded project.

Re-download a valid project using WinCC flexible. If the issue persists, perform a firmware update using the correct firmware version for the OP 77A via ProSave. If hardware failure is suspected, the unit should be inspected for internal faults.

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