User manual

5 To Trigger the Oscilloscope RIGOL
DS2000A User’s Guide
5-33
RS232 Trigger
Trigger according to the start frame, error frame, check error or data. Below is the
explanatory figure of RS232 protocol.
Trigger Type:
Press Type to select “RS232”. At this point, the trigger setting information as shown
in the figure below is displayed at the upper right corner of the screen.
Source Selection:
Press Source to select CH1 or CH2 as the Trigger Source. The current trigger
source is displayed at the upper right corner of the screen.
Polarity
Press Polarity to select the polarity of date transmission. It can be set to “Normal”
or “Invert” and the default is normal.
Trigger Condition:
Press When to select the desired trigger condition.
 Start: trigger on the start frame position.
 Error: trigger when error frame is detected. After this trigger condition is
selected:
--press Stop Bit to select “1 bit” or “2 bit”;
--press Even-OddCheck to select “None”, “Odd Checkout” or “Even Checkout”.
The oscilloscope will determine error frame according to the preset parameters.
 Check Error: trigger when check error is detected. When this trigger condition is
selected, press Even-OddCheck to select “Odd Checkout” or “Even Checkout”.
The oscilloscope will determine check error according to the preset parameters.
 Data: trigger on the last bit of the preset data bits and even-odd check bits.
When this trigger condition is selected:
--press Data Bits to select “5 bit”, “6 bit”, “7 bit” or “8 bit”;