As primeiras visitas virtuais projetadas pelo projeto ERA Virtual utilizavam-se do plugin Flash Player para a sua execução, já que esta era a melhor maneira de visualizarmos as fotografias 360º naquele momento. Com o avanço da tecnologia, novas linguagens surgiram e possibilitaram a visualização destas fotografias em HTML5, tornando o plugin Flash Player obsoleto. O suporte dos navegadores a este plugin foi encerrado em janeiro de 2021, e portanto, muitas das visitas tornaram-se inacessíveis. Nestas instruções você irá aprender a utilizá-las, bastando para isso a instalação de uma versão antiga do Mozilla Firefox, e posteriormente o plugin Flash Player.
: Ensure no active safety or communication faults exist on the drive.
Alarm A7991 is not typically a catastrophic "fault" (F) that brings the system to an immediate, emergency stop, but rather an "alarm" (A) or warning. Specifically, .
The drive displays this status code under three primary conditions:
: Ensure you know the exact Siemens product or system that's displaying the fault code. This could be a PLC (Programmable Logic Controller), a CNC machine, a medical device, or any other Siemens equipment. siemens fault 0a7991 best
Which are you using (e.g., S7-1500, SINAMICS S120)?
The isn’t a "broken" fault, but rather a digital pause: it means Motor Data Identification is Active . Think of it as your drive asking for a quick introduction to the motor it's about to spin.
| Aspect | Detail | |--------|--------| | | 0A7991 | | Display text | "CU: Internal communication error" | | Main cause | EMI, firmware mismatch, CU overload | | Best first fix | Check grounding & shielding | | Best software fix | Increase p2040 or p2079 tolerance | | Criticality | High – drive stops immediately | | Typical affected series | SINAMICS G120, S120, G130, SIMOTION | : Ensure no active safety or communication faults
This one habit prevents 80% of 0A7991 occurrences.
If the PLC is not connected, set to 0, suggests Siemens troubleshooting guides. 3. Why Does 0A7991 Return After Power Off?
: Setting this to 1 (identification at standstill) or 2 (rotating measurement). The drive displays this status code under three
: If you are in the commissioning phase, give the drive a "Run" command. The drive will perform a motor identification (at a standstill or rotating, depending on settings), often making a whistling sound. Once finished, the alarm will automatically clear.
According to Siemens technical documentation , here are the most effective methods to clear this alarm:
