Medium Precision Temperature Sensors
- Steve Gibson
- Bradford Holden (Unlicensed)
Table of Contents:
Introduction
A device that allows a large number of temperature sensors to be daisy-chained along a main branch cable. We are using these sensors throughout the system for temperature measurements that do not require the precision/accuracy/expense of a Lakeshore controller.
Relevant Devices
Description | Qty | Source | Part Number | Link |
|---|---|---|---|---|
Sensor Controller | 1 | iButtonLink | LinkHub-E 32K | |
Power Supplies | 1 |
| HubPwr5-NA | |
Splitters | TBC (Likely a couple dozen of them) | iButtonLink | T-Box - 1-Wire Splitter | (however likely any generic RJ-45 splitter would work) |
Sensors | TBC (Likely a couple dozen of them) | Maxim Integrated | DALLAS 18B20 1441C4 +800AB (label on devices used on ICON) | https://www.maximintegrated.com/en/products/sensors/DS18B20.html |
Relevant Functional Block Diagram
The sensors are connected onto short sections of ethernet cable with RJ-45 connectors. The sensors are daisy-chained together using regular ethernet cables and 1-wire RJ-45 splitters.
Connection scheme shown below to show the concept. This pattern is replicated for as many sensors as needed, with sections of regular ethernet cable used as needed to bridge sensor locations.
Note that while the cables are described here as ‘ethernet’, the communication protocol for these sensors is different than that used for computer networks.
Cable Details
Cable | Qty | Details | Notes |
|---|---|---|---|
Ethernet (Computer) | 1 | Cat6 Copper Ethernet Cable M-M, 6 feet long | Entirely within Cal Rack. |
Ethernet (Sensors) | TBC | Cat6 Copper Ethernet Cable M-M, lengths as needed to span distances between sensors. |
|
Sensor Cable | TBC | Custom cable: short length of ethernet cable with sensor on one end and RJ-45 connector on the other. |
|
Photos of Devices
Sensor Name Look-up Tables
Thermal Sensor Locations (Spectrometer and Hallway) contains the list of sensor locations.
Relevant Datasheets & Manuals
Description | File | Source | |
|---|---|---|---|
| 1 | LinkHubE User Guide |  | https://www.mfe24.com/download/LinkHub-E_Users_Guide.pdf
|
| 2 | LINK Family Manual |  | https://cdn.shopify.com/s/files/1/0164/3524/files/The_LINK_Family_Manual_1.7.pdf?7145028656254187831 |
| 3 | Command Reference
|  |
|
| 4 | Sensor Datasheet Sensor was originally developed by Dallas Semiconductor but they are now owned by Maxim Integrated |  |
Installation Instructions
Description | File
|
|---|---|
Instructions on how to change the device’s IP address over Telnet |  |
Software Details
Note that we have separate cables, however the software interface does not differentiate by cable when it combines sensor IDs into a list.