HMC Electronics MDL Series BK Precision DC Electronic Load System Module User Manual
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RS-232 Interface
Use a cable with two COM interfaces (DB9) to connect the electronic load and PC. It can be
activated by selecting <RS-232> in <Communication> of the System menu. NOTE: There are two
COM interfaces on the rear panel of the MDL001 mainframe: the left 9-pin COM interface is the
RS-232 communication interface and the right 9-pin COM serial port connection is not for use. All
SCPI commands are available through RS-232 programming. The EIA RS-232 standard defines the
interconnections between data terminal equipment (DTE) and data communications equipment
(DCE). The electronic load is designed to be a DTE and can be connected to another DTE such as a
PC COM port through a null modem cable.
NOTE : The RS-232 settings in your program must match the settings specified in the front
panel System menu. Press Shift + ⑦ on the front panel to enter the System menu if you
need to change the settings.
RS-232 Data Format
The RS-232 data is a 10-bit word with one start bit and one stop bit.
The number of start and stop bits are not programmable. However, the following parameters are
selectable in the System menu using the front panel Shift + ⑦ key.
Baud Rate
The System menu lets you select one of the following baud rates, which are stored in non-volatile
memory: 4800, 9600, 19200, 38400, 57600, or 115200.
Parity
None - eight data bits without parity
Even - seven data bits with even parity
Odd - seven data bits with odd parity
Parity=None
Start Bit
8 Data Bits
Stop Bit
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