WISH: IOC & OPI for Lakeshore 370 AC Resistance Bridge

[kjwoodsISIS]

As a WISH scientist I want to be able to control a Lakeshore 370 resistance bridge, so that I can measure and control the temperature in my experiments.

Acceptance Criteria

1. Using the IBEX client, I can control a Lakeshore 370 resistance bridge
2. Using genie_python, I can control a Lakeshore 370 resistance bridge

Notes

1. Check the WISH Instrument wiki.
2. The manufacturer's web-site describes the Lakeshore 370.
   • Note: the 370 model is now discontinued. The model 372 is its replacement.
3. A copy of the Lakeshore 370 manual is located here: \isis\shares\ISIS_Experiment_Controls\Manuals\Lakeshore__temperature_controller\Model 370.
4. There appears to be no existing Lakeshore 370 VI. Aim to provide similar functionality to existing Lakeshore IOCs/OPIs (see models 336, 340, 350 and 372).
5. There is an EPICS support module for the Lakeshore 370 device at EPICS Hardware Support.

[rerpha]

The wish VI appears to just log the resistance readings in a graph and show it in a readout box, and doesn't have any buttons. The command is the same for the 372 and 370 to do this so I suspect we can use our existing IOC for the 372 to interact with the 370. This ticket may just involve writing an OPI with the graph in.

The VI in labview modules/drivers also reads temperature, by using another VI to calculate it. We should implement this too and make it accessible as a PV.

[rerpha]

Email sent off today to scientists about usage.

[rerpha]

Ok, to confirm, on the 370 you can't just query the temperature by the looks of things, and the VI looks to do some magic to try and figure out what the temperature is from a given resistance. Here is the logic from the VI for calculating the temperature (y) with a given resistance (x):

float64 x1=x;
float64 x2=pow(x,2);
float64 x3=pow(x,3);
float64 x4=pow(x,4);
float64 x5=pow(x,5);
float64 x6=pow(x,6);
float64 x7=pow(x,7);
float64 x8=pow(x,8);

if (x >=1714 && x <= 2879)
{
        y=pow(10,(3283.88403001697 -  (11.164472250607*x1)  +(0.0165752666789975*x2)  -(1.40217255584636E-5*x3)  +(7.38921578250645E-9*x4) -2.48353721963498E-12*x5 + 5.19853402239675E-16*x6       -6.19579952030566E-20*x7 + 3.21912105889538E-24*x8 ));
}
else if (x > 2879 && x < 5887)
{
        y =pow(10,(-51.2018527792493+(0.10378459136332*x1)-(8.77905249447912E-5*x2)+(4.11090721880872E-8*x3)  -(1.17560376482219E-11*x4) +2.1092217056924E-15*x5 - 2.32346922941378E-19*x6      + 1.43916082497626E-23*x7 - 3.84294467425185E-28*x8));
}
else if (x >=5887 && x < 9210)
{
        y=pow(10,(208.130424294871 -  (0.212941317821971*x1)  +(9.32348582202883E-5*x2)  -(2.26700585766409E-8*x3)  +(3.30055787266927E-12*x4) -2.87612888293853E-16*x5 + 1.38892545664678E-20*x6       -2.86826761510268E-25*x7 ));
}
else
y=0;

converted to C:

#include <math.h>

float get_temperature(float x)
{
    float x1=x;
    float x2=pow(x,2);
    float x3=pow(x,3);
    float x4=pow(x,4);
    float x5=pow(x,5);
    float x6=pow(x,6);
    float x7=pow(x,7);
    float x8=pow(x,8);
    float y = 0.0;
    if (x >=1714 && x <= 2879)
    {
        y=pow(10,(3283.88403001697 -  (11.164472250607*x1)  +(0.0165752666789975*x2)  -(1.40217255584636E-5*x3)  +(7.38921578250645E-9*x4) -2.48353721963498E-12*x5 + 5.19853402239675E-16*x6       -6.19579952030566E-20*x7 + 3.21912105889538E-24*x8 ));
    }
    else if (x > 2879 && x < 5887)
    {
        y =pow(10,(-51.2018527792493+(0.10378459136332*x1)-(8.77905249447912E-5*x2)+(4.11090721880872E-8*x3)  -(1.17560376482219E-11*x4) +2.1092217056924E-15*x5 - 2.32346922941378E-19*x6      + 1.43916082497626E-23*x7 - 3.84294467425185E-28*x8));
    }
    else if (x >=5887 && x < 9210)
    {
        y=pow(10,(208.130424294871 -  (0.212941317821971*x1)  +(9.32348582202883E-5*x2)  -(2.26700585766409E-8*x3)  +(3.30055787266927E-12*x4) -2.87612888293853E-16*x5 + 1.38892545664678E-20*x6       -2.86826761510268E-25*x7 ));
    }
    else{
        y=0;
    }
return y;
}

I will probs use an asub record to do this

[rerpha]

hmm, they may not even use the temperature aspect of it. I am going to fire an email off to find out, as it looks like we can actually use our 372 ioc albeit with a slightly reduced db file for things that aren't supported.

email sent off but no response as of 24/08/21

[rerpha]

from the 372 manual:

The Model 372 is designed for trouble-free integration with existing equipment and software that has been built around the previous generation Model 370.

• Emulation mode on the Model 372 is designed to imitate all important communication functions of the Model 370. In most cases, programming that was previously written for the Model 370 can be used to interact with the Model 372.
• A convenient heater connector adapter (117-071) can also be purchased that replicates the BNC heater connections that were available on the Model 370, allowing connection swapping between the Model 372 and Model 370 without the need to rewire experiment cabling.