Conrad DIGI 35 CPU

Conrad DIGI 35 CPU

Status	in progress
Channels	1
Voltage/current (CH1)	0-35V / 0-2.55A
Connectivity	RS232
Features	settable values, interval and timed power-off functionality

The Conrad DIGI 35 CPU is a one-channel digitally-controlled laboratory power supply with RS-232 connectivity. It came onto the market in 1992.

Hardware

ICs

• Motorola 68HC05C4 (CPU)
• DAC-0802L (2x)
• LM-336 Voltage Reference
• TODO

RS-232 Interface

The RS-232 interface is equipped with a DB-9 socket in DTE configuration. It only receives data, but does not send any and uses no handshake lines.

Communication parameters 8n1, 9600 (power-on default), 4800, 2400 and 300 baud are supported.

To convert it to a more common DCE configuration, unplug and open the device and solder the RxD line from pin 2 of the DB-9 socket to pin 3.

Photos

• TODO

Protocol

ASCII based.

Vxxx <CR>	Set voltage to xx.x V or set special function.
Cxxx <CR>	Set current to x.xx A.
L <CR>	Lock keyboard.
E <CR>	Enable keyboard.
U <CR>	Increase voltage by 100 mV
U <CR>	Decrease voltage by 100 mV

Special functions:

5xx	Set interval 01-99 seconds. The output is switched on and off in the interval. Use with care because of wear of relay! Set to 00 to disable.
6xx	Set countdown to 01-99 hours. After countdown has expired, the output is disabled. Set to 00 to disable.
7xx	Set countdown 01-99 minutes. Can be combined with 6xx. Set to 00 to disable.
800	Set baud rate to 300.
801	Set baud rate to 2400.
802	Set baud rate to 4800.
803	Set baud rate to 9600.
900	Set current mode to overcurrent protection (reaching current limit disables output).
901	Set current mode to constant current (default).
902	Lock keyboard (unlock via RS-232).

Resources

• Manual (German): http://www2.produktinfo.conrad.com/datenblaetter/500000-524999/512982-an-02-de-Programmierbares_Netzteil_DIGI_35_CPU.pdf