Tenma 72-2540 low voltage power supply remote control

Lab setup during Covid-19 teleworking (TL;DR)

The power supply powers the whole caribou setup. It is connected to PCLCD51 where it can be accessed through /dev/ttyACM0. Two shell scripts can be found in caribou home directory (/home/caribou/): pwrSupplyOn.sh and pwrSupplyOff.sh.

pwrSupplyOn.sh first switches the supply output off, then sets it to 12 V, 1.5 A and enables OCP (Over Current Protection). As a last step it switches the output on. You can use this script to power-on or power-cycle the board.

pwrSupplyOff.sh switches the supply output off. Use it to power the setup off.

Both scripts call python scripts located in /home/caribou/tenma-serial/.

General description

The device can be controlled over a serial interface. One can connect either over an RS-232C or USB port. The USB port has a built-in USB-to-serial converter, that presents itself as an ACM device on the USB side. So it typycally maps to /dev/ttyACM0 on a linux machine. You can talk to it using any serial terminal software or also by redirecting the keyboard input to the corresponding device (e.g. /dev/ttyACM0). The serial port settings and list of commands is further down on this page.

The other way is to use scripts that translate a bit more user friendly interface to the serial commands. For example: https://github.com/kxtells/tenma-serial

Serial port settings

• Baud rate: 9600
• Parity bit: None
• Data bit: 8
• Stop bit: 1
• Data flow control: None

Serial port command format

• COMMAND<X>:<NR2>
• COMMAND<X>?
• COMMAND<Boolean>
• COMMAND<NR1>

• <X> Output channel (always 1 in case of a single channel supply 72-2540)
• <NR1> Digits with an implied decimal point assumed at the right of the least-significant digit. Example: 273 (Integer number)
• <NR2> Digits with an explicit decimal point. Examples: .273, 0.273
• <Boolean>: Boolean value 1 or 0.

List of serial port commands

ISET<X>:<NR2>

• Description: Sets the output current
• Response time: 50ms
• Example: ISET1:2.225 sets the CH1 output current to 2.225A

ISET<X>?

• Description: Returns the output current setting
• Example: ISET1? returns the CH1 output current setting.

VSET<X>:<NR2>

• Description: Sets the output voltage.
• Example: VSET1:20.50 sets the CH1 voltage to 20.50V.

VSET<X>?

• Description: Returns the output voltage setting.
• Example: VSET1? returns the CH1 voltage setting.

IOUT<X>?

• Description: Returns the actual output current.
• Example: IOUT1? returns the CH1 output current.

VOUT<X>?

• Description: Returns the actual output voltage.
• Example: VOUT1? returns the CH1 output voltage.

BEEP<Boolean>

• Description: Turns on or off the beep.
• <Boolean>: 0=OFF, 1=ON.
• Example: BEEP1 turns on the beep.

OUT<Boolean>

• Description: Turns on or off the output.
• <Boolean>: 0=OFF, 1=ON.
• Example: OUT1 turns on the output.

STATUS?

• Description: Returns the POWER SUPPLY status.
• Contents 8 bits in the following format:
  • bit 0: CH1 mode: 0=CC, 1=CV
  • bit 1: N/A
  • bit 2: N/A
  • bit 3: N/A
  • bit 4: Beep: 0=Off, 1=On
  • bit 5: Lock: 0=Lock, 1=Unlock
  • bit 6: Output: 0=Off, 1=On
  • bit 7: N/A

*IDN?

• Description: Returns the device identification.
• Example: *IDN? returns manufacturer, model name, serial number: TENMA 72-2540 SN:xxxxxxxx Vx.xx

RCL<NR1>

• Description: Recalls a panel setting.
• <NR1>: Memory number 1 to 5.
• Example: RCL1 recalls the panel setting stored in memory number 1.

SAV<NR1>

• Description: Stores the panel setting.
• <NR1>: Memory number 1 to 5.
• Example: SAV1 stores the panel setting in memory number 1.

OCP<Boolean>

• Description: Over current protection.
• <Boolean>: 0=OFF, 1=ON.
• Example: OCP1 turns on the OCP

OVP<Boolean>

• Description: Over voltage protection.
• <Boolean>: 0=OFF, 1=ON.
• Example: OVP1 turns on the OVP