ES237 Datasheet, PDF (27/37 Pages) Cyrustek corporation – 6000 Counts DMM

ES237
6000 Counts DMM
4. Serial Data Output
The RS232 function will be activated if press down the REL key and last for 2 seconds, RS232
symbol will be shown on the LCD display. The serial data sent to SDO pin periodically at every A/D
conversion cycle by 15 times per second. The data format complies with 8Bits transmission code with
a baud rate of 9600. The host can use RS232 interface to read the data. A single data packet includes a
start bit (always 0), 8 data bits with no parity check bit, and a stop bit (always 1). The high and low
voltage levels correspond to DGND and V- respectively. SDO remains at 1 (high) when it is inactive.
Hence the start bit (0) could be used as the triggering signal to begin the reading process. The
following figure shows the data format of a single packet.
Single packet
0V
0 1 ^{D7 D6 D5 D4 D3 D2 D1 D0}
-3V
MSB
LSB
One data block consists of 17 packets. The following figure shows the format of a data block. The
Header and Device code leads the whole packets. The range packet indicates the decimal point
position on LCD panel of meter. Main_Digit1-3 consists of the readings on the LCD panel. The
function packet indicates the measurement mode of the meter. Status1-4, Unit and Bargraph give the
other status of the meter. CR and LF are delimiters used to separate the blocks.
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2015/12/15