Today, I will present an example of interference from a variable frequency drive (VFD) on a PLC’s analog signal and a solution using a signal isolation module to overcome such interference. 1. Example 1: Description of the Phenomenon In a Siemens PLC, an AO point outputs a 4-20mA current control signal to a Siemens VFD, … Read more
1. CPU Abnormality When a CPU abnormality alarm occurs, check all devices connected to the internal bus of the CPU unit. The specific method is to replace the potentially faulty units one by one to identify the faulty unit and take appropriate action. 2. Memory Abnormality When a memory abnormality alarm occurs, if it is … Read more
Signal Isolation Once we have resolved the design and control issues of the switch structure, the next question is to determine the isolation strategy. Each interface in the power gating area needs to be managed. We need to ensure that turning off the power in this area does not cause short-circuit currents at the inputs … Read more
In low power designs with multiple power domains, there are many interactive signals between different power domains. If one power domain is powered off, the signals output from that power domain to another power domain that is still powered on need to be isolated. The reason is that the signals from the powered-off power domain … Read more
Today, I will present an example of interference from a variable frequency drive (VFD) on a PLC’s analog signal and a solution using a signal isolation module to overcome such interference. 1. Example 1: Phenomenon Description In a Siemens PLC, the AO point outputs a 4-20mA current control signal to a Siemens VFD, but it … Read more
In the field environment of Profibus, we use a variety of systems, and the devices we face interference from are diverse, so the sources of interference are also varied. Many failures caused by interference are more difficult to troubleshoot than other faults. Before troubleshooting interference failures, we need to understand the types of interference. In … Read more
In the field environment of Profibus, the systems we use are diverse, and the devices we are interfered with are varied, so the sources of interference are also peculiar. Many failures caused by interference are more difficult to troubleshoot than other failures. Before eliminating interference faults, we need to understand the types of interference. To … Read more