epicsdev_ps_caen_easydriver

EPICS PVAccess server for CAEN EASY-DRIVER power supplies.

Requires Python 3.11 or newer. The package includes epicsdev for the server and phoebusgen for generating the Phoebus operator interface.

This server implements remote control over TCP/IP using the EASY-DRIVER command set from:

• misc/programming_manual.pdf

and exposes the same operational PV names as in:

• misc/devEasyDriver.db

Implemented PVs

The server hosts these PVs (same names as the DB records):

• Version
• Enable
• Reset
• SlewControl
• Setpoint
• BulkVoltage
• RegulatorTemp
• ShuntTemp
• OutputVoltage
• SupplyOn
• GenericFault
• FETovertemp
• ShuntOvertemp
• DCunderV
• ExternalInterlock1
• CurrentRBV
• SlewControlRBV
• ControllerKp
• ControllerKi
• ControllerKd

Additional PVs are Model, Identification, CurrentLimit, Status, Connected, SlewRate, SlewRateRBV, host, port, and dateTime. Status is the eight-bit register from the manual: output enabled (bit 0), fault (1), DC undervoltage (2), MOSFET overtemperature (3), shunt overtemperature (4), and external interlock (5).

Command mapping summary

Runtime polling and status use:

• MST → status bits
• MRI → current readback
• MRV → output voltage
• MRP → bulk/DC-link voltage
• MRT → MOSFET temperature
• MRTS → shunt temperature

Startup reads MVER for model and firmware version, MRID for identification, and MRG for the current limit and stored PID gains.

Control operations use:

• MON / MOFF → enable/disable output
• MRESET → reset status/fault state
• MWI / MRM → setpoint write (immediate/ramped)
• MWG + MPUP → controller gains (Kp, Ki, Kd)
• MRG → read stored gain values
• MWSR / MRSR → write/read ramp slew rate (0-1000 A/s)

Startup only reads hardware configuration; it never enables the output or replays saved current setpoints. CurrentLimit comes from EEPROM cell 4; --range can reduce, but cannot increase, this limit. Setpoint records the last accepted server write, not a queried hardware setpoint. It initializes to zero and resets to zero after MON, as specified by the manual. SlewControl selects the server's MWI/MRM command policy, and its readback is local to the server. PID gain writes require the output to be off and write EEPROM before applying the settings with MPUP.

Commands and replies are CR-terminated. Failed puts return a PVAccess error; failed polling retains the last valid measurements and clears Connected. Broken connections are reopened on the next transaction, without replaying the failed command. Exiting the server closes TCP but does not turn off the supply.

Installation

From this project directory, install the server and OPI generator dependencies:

python -m pip install .

For development, use an editable installation instead:

python -m pip install -e .

Running

Example:

python -m epicsdev_ps_caen_easydriver --host 192.168.0.10 --port 10001

Useful options:

• positional device prefix base (default: caen_edrv)
• -i, --instance device instance (default: 0)
• --host EASY-DRIVER IP/host (default: 192.168.0.10)
• --port EASY-DRIVER TCP port (default: 10001)
• --timeout socket timeout in seconds (default: 2.0)
• --range restrict setpoint magnitude in A (default: hardware limit)

Use python -m epicsdev_ps_caen_easydriver --help for all server options.

The published PV prefix is:

• <device><instance>:

With defaults, PVs are published as:

• caen_edrv0:<PVName>

Phoebus OPI

Example operator interface: caen_edrv0.bob.

Generate the operator interface from this project directory:

python opi/generate_opi.py

The generator writes opi/caen_edrv0.bob with the default PV prefix pva://caen_edrv0:. Open the generated screen in Phoebus with PVAccess support enabled and the server running.

The screen includes server controls, device identification and connection status, output current and voltage meters, a current setpoint slider and entry, slew settings and readbacks, temperatures, stored PID gains, and the status register with individual status flags. Write 1 to Reset to reset the module status register. PID gain writes require the output to be off.

To use another server prefix and screen title:

python -m epicsdev_ps_caen_easydriver magnet -i 1 --host 192.168.0.10

In another terminal, from this project directory:

python opi/generate_opi.py --title "Magnet 1" pva://magnet1:

The prefix must include the trailing colon. The title and prefix options do not change the output filename: the generator still writes opi/caen_edrv0.bob, replacing any existing screen at that path.

Tests

Run from this project directory with its dependencies installed:

python -m unittest discover -s tests -v

The tests use simulated device replies and do not connect to a physical supply.