Masterofplc.com | Automation Excellence Gateway

So how to set up the power-off data retention function for S7-1200? S7-1200 module (Photo: siemens.com/global) During operation, an unexpected power outage may occur, and the equipment operators hope that certain key data can be preserved in such cases to ensure the normal operation of subsequent production. The S7-1200 series PLC features a retained storage area that can be used to set power-off retained data. In this article, we will discuss how to set up the power-off data retention function for S7-1200. First, let's understand the composition of the internal storage area of the S7-1200 series PLC: The internal storage area of the S7-1200 includes the Load Memory, Work Memory, and Retain Memory. Load Memory: This is a non-volatile storage area, similar to a computer's hard disk. The Load Memory is used to store user project files (user programs, data, and configurations). When no memory card is inserted, users use STEP 7 software to download projects directly...

Beckhoff TwinCAT basic tutorial: How to read and write CSV files with TwinCAT

This program is only a slight modification of the official sample program. In the original official sample, multiple modes of reading and writing are demonstrated (CSV files can be considered to be used when more data is required than TXT files, such as recording a small database collection). However, the writing is quite confusing, and there is even no HMI interface. Readers need to learn how to quickly find the input and output in the program, such as TextModeWrite (writing CSV files in text mode). At least they need to locate the variables of the triggered BOOL variable, the file address and folder to be written, and the data to be written (where the data to be written is an array of string type, separated by commas). You can directly open the official program and run it. You can also directly set and reset bWrite in the variable table at the top to test the program's operation. However, it is not conducive to analysis. After two months, you may forget how to make this thing run...

Pilz Safety Relays ｜How to Use Pilz Safety Relays (Includes Wiring Diagram)

How to Use Pilz Safety Relays?(Includes Wiring Diagram) A robust control system must first and foremost be a secure system—capable of ensuring the safety of individuals and equipment in the event of system failures or emergency shutdowns. When it comes to safety automation systems, the mention of Germany's Pilz company is inevitable. Pilz has been deeply rooted in the field of safety automation for decades, offering a range of safety products, including safety PLCs, safety switches, and safety relays. Notably, Pilz pioneered the development of the first safety relay (PNOZ) for emergency stops, gaining widespread recognition worldwide. Since then, PNOZ has become synonymous with safety relays. Today, Pilz offers a variety of PNOZ safety relay series, such as PNOZsigma, PNOZ X, PNOZcompact, PNOZelog, each with different models. In this article, we will take PNOZ X3 as an example to discuss the usage of safety relays for emergency stop buttons. The appearance of PNOZ X3 is depicted i...

Siemens module passivation and reintegration

What is the passivation and reintegration of a Siemens fault-tolerant module? In fault-tolerant systems, alarms for "passivation" of the fault-tolerant module may sometimes occur. So, what exactly is passivation? Why does passivation occur in fault-tolerant modules? After passivation occurs, how can it be reintegrated to eliminate passivation? Today, in this article, we will delve into this topic. Passivation refers to the phenomenon where, under certain conditions, a fault-tolerant module replaces normal input/output values with fault-safe values, typically 0. Passivation serves as a safety measure, and it occurs under specific circumstances. First, let's introduce several boolean variables related to passivation in the background data block (Instance DB) of the fault-tolerant module: PASS_ON: The enable bit for passivation, defaulting to 0, indicating that passivation is not enabled. The fault-tolerant program can read and write to it; to activate passivation, set PA...