# 5.4.1.2. USB Latency Timer 延遲定時器設置

在 Linux（ubuntu）環境中，USB latency time 延遲時間預設為 16ms。按照以下步驟將 DYNAMIXEL 智能馬達和通過 USB 連接的 PC 之間的通信延遲時間，設置為最低值（1ms）。

打開 terminal 終端窗口並運行 roscore。

```
$ roscore
```

在運行 roscore 的情況下，打開一個新的終端窗口並輸入以下指令來設置 usb 延遲時間。

```
$ rosrun open_manipulator_controller create_udev_rules
```

{% hint style="info" %}
TIP：此輸入指令將 USB 延遲計時器設置為 1 ms。如果要查看該設置，請在終端中執行以下指令。 

cat /sys/bus/usb-serial/devices/ttyUSB0/latency\_timer
{% endhint %}


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