RE: How to add KeySight Laser interferometer to EPICS

[Freddie Akeroyd - STFC UKRI via Tech-talk <tech-talk at aps.anl.gov>]

Hi,

 

If you want to serve the values as PVs then some options are:

 

• Use  the python ctypes module https://docs.python.org/3/library/ctypes.html to call the DLL function, then use pyepics to push these values into PVs on a separate EPICS  softioc process. Gets a bit more messy if you want to do read/write via the IOC, but is a good proof of principle
• Create a python PV server using pcaspy (to serve pvs via channel access) or p4p (serve pvs via PVaccess) and then have this access the DLL via ctypes

 

Non python solutions would be to either create EPICS aSub records to read/write values and build these into an IOC,  or create an EPICS asyn driver to do similar – both of these approaches would require some knowledge of the native system shared library load and call mechanism

 

Regards,

 

Freddie

 

From: Tech-talk <tech-talk-bounces at aps.anl.gov> On Behalf Of l123173 via Tech-talk
Sent: 24 March 2025 09:06
To: tech-talk <tech-talk at aps.anl.gov>
Subject: How to add KeySight Laser interferometer to EPICS

 

Hi all,

       I have a Laser interferometer of KeySight 5519A/B，which data was collected through E1735A.

       I met two question when i try to put E1735A in EPICS.

       1) E1735A only has dll, the dll run in windows. 

            I don't know how to add the dll in epics and i have both win epics and linux epics.

       2) The dll has some function, which we have to use.  

           The function return the point of values buffer and the number of values.  The number of values was changed according the interval time. The function could send 255 values most each time. And we must invoke it frequently.

           So i think it is not possibile to transfer these values to pv using pyepics.

 

        Does anyone know how to solve it. Any suggesion was appreciate.

 

Regards,
Liang

 

The function:

int E1735A_ReadAllSamples(TLaserSample* pBuf, int BufSize)

typedef struct {

             double LaserPos;  //sample value

             __int64 TimeStamp;  // time stamp

             int LaserTriggerl;    //trigger

             int LaserError;       //error code

} TLaserSample