MercuryiTC

Wiki > The Backend System > Specific Device IOC > Temperature Controllers > Mercury iTC

The Mercury iTC is a configurable temperature controller from oxford instruments ( Manual ).

It contains various slots into each slot a variety of devices can be placed. For the purposes of this document the motherboard is treated as a slot too, it contains a temperature sensor and a heater.

Types of daughter boards are:

• temperature sensor
• Heater
• Auxiliary board (general purpose and stepper motors)
• Pressure sensor
• Cryogen
• GPIB board (communications)

In the future, we may want to develop a full epics IOC for it and there is a possible Diamond IPC driver at http://controls.diamond.ac.uk/downloads/support/OxInstCryojet/ currently there is an LvDCOM driver.

Communications

The device should be talked to via serial at a baud rate of 57600. This is variable on the front panel, but only while the device is in local mode.

The screens look like:

Driver

Currently, the driver only measures and sets the following:

• Temperature
• He Level
• Pressure

There is a section on each below as well as how to se the communication settins.

Communication Settings

The driver is an lvdcom driver and so to change the com port you must configure the labview code. To do this open the setup vi which is in C:\LabVIEW Modules\Drivers\Oxford Instruments\Mercury\Mercury - System Functions.llb and is called Mercury - System Functions.llb. Run this dialogue and edit the settings for the correct Mercury. To apply these settings you will need to restart the mercury vi.

Temperature

Setup

To activate a card you must set the related IOC macro. The macro sets the final part of the front panel name. The front panels are called Temperature: Mercury - Front Panel <I> - Temp <N>.vi where is the Mercury index (also the IOC index) and is the card index 1 for the first temperatue card, 2 for the second etc. The following macros set the for the possible IOC slot:

Macro	Usual Value	IOC Name
MERCURY_01__VI_TEMP_1	1	%MYPVPREFIX%MERCURY_01:1
MERCURY_01__VI_TEMP_2	2	%MYPVPREFIX%MERCURY_01:2
MERCURY_01__VI_TEMP_3	3	%MYPVPREFIX%MERCURY_01:3
MERCURY_01__VI_TEMP_4		%MYPVPREFIX%MERCURY_01:4
MERCURY_02__VI_TEMP_1		%MYPVPREFIX%MERCURY_01:LEVEL:1
etc

Important PVs

• TEMP Current temperature
• TEMP:SP Setpoint for temperature controller
• TEMP:SP:RV Read back of the set temperature point
• NAME Name associated with the card

He Level

The helium level can be monitored by setting the macro VI_LEVEL_N to point at the correct vi in a similar fashion to the temperature.

Pressure

A pressure card can be monitored by setting the macro VI_PRESSURE_N to point at the correct vi in a similar fashion to the temperature.

Example

In this example the front panel on the Mercury look:

NB The device should be in remote mode this is indicated by the i (bottom left) having an orange background. This mercury has 3 temperature sensors, Sample_Rod, VTI_DB6 and PT2_DB7, the VTI has a heater attached to the second temperature. This means it needs:

• VI_TEMP_1 set to 1,
• VI_TEMP_2 set to 2,
• VI_TEMP_3 set to 3,

The temperature controls are on the 1st and 2nd temperature and so on the first and second tab on the mercury device screen. NB the device screen also needs these macros set.

This also has a pressure gauge which we currently can't read remotely.

For info here is a detailed temp loop:

OPI

The OPI has macros that relate to the macros set at the IOC level.

Troubleshooting

Mercury doesn't communicate

1. One issue we have seen is that when the Mercury is transferred between instruments, or during some initial configuration, a user will change values like the Baud rate. It's good practice to check the devices settings (baud rate etc) and the one on the set-up dialog for the Mercury VI to ensure parity between them.
2. Ensure that it is set to remote mode. On the front panel the i, bottom left, should have an orange background.

Pressure card won't read heater voltage correctly

This may be accompanied by an error in the ioc log:

2019/12/15 16:18:04.417 TE:NDW1799:MERCURY_01:PRESSURE:2:HEATER:VOLT devAsynFloat64 process read error lvDCOMDriver:readFloat64: status=0, function=13, name=HEATER:VOLT, value=0.000000, error=LabVIEW : parameter %p not found in the VI's connector pane. : IDispat

If this is the case, you need to get the latest version of Mercury - Pressure.vi from sourcesafe. Older versions had two parameters with the same name, which LvDCOM could not cope with correctly.