High Precision Temperature Sensors
- Steve Gibson
- Bradford Holden (Unlicensed)
Table of Contents:
Introduction
Three Lakeshore controllers are used for high precision temperature telemetry within KPF.
Relevant Devices
Description | Qty | Source | Part Number |
|---|---|---|---|
Green Lakeshore | 1 | Lakeshore | 224-12 |
Red Lakeshore | 1 | Lakeshore | 224-12 |
Spectrometer Lakeshore | 1 | Lakeshore | 224-12 |
RTD Sensors | 36 | Honeywell | Honeywell PN: HRTS-5760-B-U-1-12 |
NOTE: we have three identical devices. The same KTL dispatcher is used for all three, however each device has a its own configuration file as described within the “Dispatcher Configuration File” section below.
Relevant Functional Block Diagram
The three Lakeshores will be set up the same, with sensors placed within (or around) the vacuum chamber. The temperature sensor cable details differ depending on where the sensors are placed, see “Installation Details and Sensor Locations” table below for more details.
Installation Details and Sensor Locations
Description | File | Notes | |
|---|---|---|---|
| 1 | Installation details and sensor locations | ||
| 2 | Interconnection Diagram |  |
|
| 3 | Sensor cable harness fabrication details |  |
|
| 4 | Cable details between Lakeshores and vacuum chamber | ||
Relevant Datasheets & Manuals
Description | File | Source | |
|---|---|---|---|
| 1 | Device Manual |  | |
| 2 | Rack Mounting Instructions |  | |
| 3 | RTD Sensor Datasheet |  Covers many sensors, the part number of the sensor KPF uses is: HRTS-5760-B-U-1-12. | DigiKey download. |
Dispatcher Configuration File
Each Lakeshore has a unique name, noted as $(NAME). Currently the names are green and red but that can easily change. That name is used to denote details about the connections.
Each sensor has a unique name, noted as $(sensor). That name is set by the configuration file. The keyword for the sensor is set by the sensor name. The units, data type, and display format are also all defined in the configuration file.
Note, beyond the blocks device and dispatcher each sensor needs its own block. That block named by the sensor name, so, A, B, C1, etc.
Configuration | Value | Explanation |
|---|---|---|
address | 192.168.23.181 | IP address of the Lakeshore |
port | 7777 | port for connecting to the Lakeshore |
poll_time | 5 | Time in seconds between queries |
model | MODEL224 | Model number for the device, must in the return string when the model is queried |
name | green | Prefix of name, corresponds to which Lakeshore (could be removed) |
dispnum | 2 | Dispatcher number. |
name | sensor | Name of the sensor, must be in a block labeled by the internal sensor name (e.g., A, B, C2, etc.) |
type | double | The data type of the value |
format | %.3f | The ASCII format used for showing the data via KTL. The full data as returned by the device will be stored in the binary format. |
unit | deg C | The units of the temperature. The options that actually make sense are deg C and deg K. There is no enforcement of that here but this only impacts the displayed values, it does not change the query made to the device (which can be K or C.) |