Technical Analysis and Application Guidelines for Siemens TP 170A, TP 170B, and OP 170B Operation Panels
In industrial automation systems, human-machine interface (HMI) is a key component for implementing equipment monitoring, parameter setting, and process intervention. The TP 170A, TP 170B touch screens, and OP 170B operation panels under the Siemens SIMATIC HMI series are classic products for mid to low end applications. With their reliable performance, flexible configuration, and strong environmental adaptability, they are widely used in industries such as mechanical manufacturing, packaging, automotive, and chemical. This article is based on the official equipment manual, systematically analyzing the technical architecture, functional configuration, installation, debugging, and maintenance points of these three devices, providing comprehensive application references for engineering and technical personnel.
Product Overview and Positioning
TP 170A, TP 170B, and OP 170B belong to the "Low end Units" in the SIMATIC HMI series, all using Microsoft Windows CE operating system, which combines cost-effectiveness and functional practicality. Among them, TP 170A is an economical entry-level product that supports all SIMATIC S7 series PLCs; On this basis, TP 170B and OP 170B have enhanced functions such as graphic display, message processing, and recipe management to meet more complex process monitoring requirements.
These three devices all have an IP65 front panel protection level and are designed without a hard drive or fan, making them suitable for direct installation in cabinets or workstations in harsh industrial environments such as dust and oil pollution. Its communication interface supports MPI, PROFIBUS-DP, and various third-party PLC protocols, making it easy to integrate into existing automation networks.
Hardware structure and core functions
1. Display and operation unit
TP 170A/TP 170B: Equipped with a 5.7-inch STN LCD screen, with a resolution of 320 × 240, supporting 4-level blue tone or 16 color display. The operation mode is a resistive touch screen that supports finger or stylus input.
OP 170B: Also a 5.7-inch screen, but equipped with an integrated film keyboard, including 35 system keys (including 3 with LED indicator lights) and 24 configurable function keys (including 18 with LEDs), suitable for scenarios with frequent data input and function calls.
2. Processor and Storage
The device is equipped with a 32-bit RISC processor and runs Windows CE system. The TP 170A has a configured memory of 320 KB, while the TP 170B and OP 170B have 768 KB. They support storage expansion through CompactFlash (CF) cards for recipe data, project backup, and more.
3. Communication interface
IF1A: RS232 serial port, used to connect programming units (PU/PC) or partial PLCs.
IF1B: Supports RS422/RS485 (electrical isolation) and can be configured as MPI or PROFIBUS-DP interface through dip switch.
IF2 (TP/OP 170B only): RS232 serial port, commonly used for connecting printers or configuring computers.
The power interface is a 2-pin terminal that supports 24 VDC safe extra low voltage (SELV) and has reverse polarity protection.
4. Summary of core functions
Screen objects: support text, graphics, input/output fields, buttons, status buttons, bar charts, trend views, message displays, recipe views, etc.
Message system: supports event messages, alarm messages (to be confirmed), and HMI system messages. TP/OP 170B also supports message buffering, printing, and archiving.
Recipe Management (TP/OP 170B only): It can create, edit, and store recipe data records, support transfer from/to PLC, and can be imported and exported through CSV files.
Multi language support: Up to 5 languages can be loaded, allowing for online switching of screen text, messages, and other content.
Password protection: Supports multi-level (0-9) password permission management to ensure operational security.
Configuration and Project Download
The device is configured through ProTool CS (including ProTool/Pro CS, ProTool/Lite). The configuration steps are as follows:
Project creation: Use ProTool CS to design graphics, define variables, and configure communication connections on the configured computer.
Communication settings: Connect HMI and PC through serial port or MPI/PROFIBUS interface. Select "Transfer" mode in the HMI startup menu and enable the corresponding channel and "Remote Control" option in "Transfer Settings" for automatic download.
Download project: Select "Download" in ProTool CS and transfer the compiled project file (. fwd) and running system to HMI. If you want to keep the source file for future modifications, you can check the "Upload" option and store the project in compressed format (. pdz) on the CF card of the HMI.
Testing and debugging: HMI can test the screen logic in offline mode and communicate with PLC in online mode. ProTool CS has a built-in simulator that can verify projects without hardware connection.

Installation and Wiring Guide
1. Mechanical installation
Installation hole size: TP 170A/TP 170B is 198 × 142 mm (tolerance -0/+4 mm), OP 170B is 229 × 241 mm.
The thickness of the panel shall not exceed 6 mm (not exceeding 3 mm when using a protective cover).
Secure the sealing strip tightly against the panel from the back using the accompanying snap on screws, achieving IP65 protection.
2. Electrical installation
Power supply: 24 VDC (range 18-30 V), connected through 2-pin terminals, recommended to use 2.5 mm ² wire.
Grounding: Connect the cabinet to the ground through the grounding screw on the equipment, and it is recommended to use copper wire with a diameter of ≥ 2.5 mm ².
Communication line: Shielded cables must be used to avoid parallel laying with power lines. Attention should be paid to equipotential connection in PROFIBUS networks, and it is recommended to use 16 mm ² equipotential wires.
Printer connection (TP/OP 170B only): Connect a serial printer through the IF2 interface, and match the baud rate (9600-57600) and data format (8N1) in the printer settings.
Key points of operation and maintenance
1. Daily operations
Touch screen operation: Lightly touch the screen elements (buttons, input fields, etc.) to avoid using sharp objects. TP 170B supports the "direct key" function and can quickly respond to key operations through PROFIBUS.
Keyboard operation (OP 170B): Function keys can be defined as global or screen specific functions. Combination keys (such as Shift+cursor) are used for navigation and editing.
Message confirmation: Alarm messages need to be confirmed through the ACK key or screen button to prevent the accumulation of unresolved faults.
2. System settings
Screen calibration (TP series): recalibrate touch points in the Control Panel or through the "Touch Calibration" function to avoid operational deviations caused by installation angles.
Language switching: Call the "Language" function through the configured function keys to switch the operating interface language in real time.
Time synchronization: HMI and PLC clock synchronization can be achieved through PLC jobs (Job 14/15) or area pointers.
3. Data backup and recovery
Using ProSave tool: can backup/restore the entire Flash image, recipe, password list, etc., supporting serial port or MPI transmission.
Using CF card: Select "Backup/Restore" in the Control Panel to save the system image to the CF card for quick recovery or device replacement.
4. Cleaning and maintenance
When cleaning the screen, please turn off the power and use a soft damp cloth dipped in a small amount of cleaning agent to wipe. Do not spray liquid directly.
The TP series can be equipped with protective film or cover to enhance its resistance to scratches and chemical corrosion.
The OP 170B keyboard label can be customized for printing and replacement, and the template file is located in the Utility folder of the ProTool CS installation disk.
Fault diagnosis and system updates
The device may trigger HMI system messages during operation, indicating issues such as communication interruption, incorrect tag address, and insufficient storage space. Appendix C of the manual provides common message codes and handling suggestions, such as:
Message 140001: Interrupted connection with PLC, check cables, PLC power supply, and communication parameters.
Message 230000: Input value exceeds range, confirm variable upper and lower limit settings.
Message 190000: Tag update exception, check PLC address matches data type.
If the download fails due to an incompatible operating system version, the PTUpdate tool needs to be used to rewrite the operating system image (. img file) through the serial port. This process will clear all data in the device and requires backup in advance.
