HAMEG
Instruments

Description of interface commands
Date: 15th September 2003 Valid for oscilloscopes: HM305-2, HM404, HM404-2, HM407, HM1004-2, HM1004-2A, HM1004-3, HM1505-2, HM1507, HM1507-2, HM1507-3, HM2005. RS-232 cable A 9 conductor serial interface cable (1:1 connection, i.e. without crossed pin connections ) will be required to connect the oscilloscope to an external instrument. Setting the baud rate The RS 232 interface must be initialized before use. This is effected by the first transmission of SPACE CR (20 hex., 0D hex.) after POWER UP (switching on). This will automatically set the baud rate. The following baud rates will be recognized: 110 150 300 600 1200 2400 Data transmission format: Baud Baud Baud Baud Baud Baud 4800 9600 19200 38400 56700 115200 Baud Baud Baud Baud (1.19 Baud (1.19 Baud (1.19

No parity, data length 8 bits, 2 stop bits, RTS/CTS handshake.

If the PC has a COM interface with FIFO buffer, then the maximum depth of the send buffer must be set to 8 bytes. The baud rate set will remain operative until POWER DOWN (switch off) or until the remote mode is disabled with the command ‘RM0’, or until the pushbutton LOCAL (AUTOSET button) is activated, assuming this is not inhibited (LK=0). Once the remote mode is disabled, the data transmission can be only restored by again sending SPACE CR. If the oscilloscope does not recognize SPACE CR as first characters, or if Low-level exists on the RTS line longer than for about 2 seconds, then the oscilloscope exits the remote mode and sets the TxD Low for about 0.3s and thus generates a frame error. The oscilloscope answers with a RETURNCODE (0 CR LF) if it has recognized SPACE CR and has set the baud rate. The scope sends ‘ESC RMLK=0’ (ESC=1B hex.) and exits the Remote state if the button LOCAL is activated in Remote-ON state. The time between the reception of the RETURNCODE Remote-OFF and Remote-ON must be at least tmin= 2*(1/Baudrate) + 60µs

Interface commands for HM305-2, HM404,