Troubleshooting Encoder Totem Pole Output Issues with PLC

When dealing with encoders and programmable logic controllers (PLCs), it's not uncommon to encounter issues with reading the pulse output from the encoder. In this article, we'll explore some common causes of these problems and provide potential solutions.

One possible reason for the issue is that the encoder may not have a common signal with the PLC input. This can cause the PLC to read the input as a floating signal, leading to incorrect readings. To resolve this, ensure that the encoder's common signal is connected to the same terminal as the PLC input.

Another potential cause of the problem is that the PLC may not be able to retain its settings or values when it's turned on and off. This can result in the pulse reading being lost. To overcome this issue, check the PLC program to ensure that it's configured correctly for retaining settings.

When setting up the encoder with the PLC, it's essential to configure the input connections properly. In some cases, connecting the potential (24VDC) to the PLC input common may not be necessary. However, if the PLC i/p phase A & B gives 0V potential to the PLC input terminals, the encoder storage bits will still show the pulse reading.

To set the count starting from 0 to 1000, you can configure the PLC program accordingly. This may involve using a specific instruction or function block in your PLC programming software. For example, you can use the 'PRV' instruction to set the count.

In some cases, the issue may occur due to incorrect input settings. Try adjusting the input setting from 'Pulse+Direction' to 'Circular Count 1000' and see if that resolves the problem.

Finally, ensure that your PLC is configured correctly for high-speed counter mode. In this case, you can set the high-speed counter to 0 and the maximum count to 1000.

In summary, troubleshooting encoder totum pole output issues with a PLC requires attention to detail and careful configuration of the input connections and PLC program. By following these tips, you should be able to resolve common problems and achieve accurate pulse readings from your encoder.

Encoder totem pole output