TTL, voltage, one-wire test rig

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Discussion Overview

The discussion revolves around the creation of a test rig for environmental sensors connected to a data logger, focusing on evaluating outputs from various sensor types (serial TTL, analog voltage, 1-wire) and ensuring proper signal transmission. The scope includes technical challenges, design considerations, and user-friendliness for non-expert users.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant suggests using a DSO203 Pocket-Sized Oscilloscope for testing, but expresses concern about its usability for non-experts.
  • Another participant proposes using a microcontroller (uC) for communication testing, asking about available development boards and the specifics of the communication paths.
  • There is uncertainty about the functionality of the GPIO pins and their configuration, with one participant noting they were wired by an electrician without their input.
  • A suggestion is made to consider the CY8CKIT-050 development kit for implementing GPIO testing, although the original poster lacks experience with embedded systems.
  • One participant questions the purpose of the test kit, suggesting it should be user-friendly for field engineers and capable of providing pass/fail indications for sensors.
  • Another participant emphasizes the importance of understanding signal characteristics and communication protocols, noting that improper cable termination can lead to communication issues.
  • The original poster expresses frustration about the lack of resolution and clarity in the discussion, questioning whether they should seek help elsewhere.

Areas of Agreement / Disagreement

Participants express differing views on the best approach to creating the test rig, with no consensus on the most effective tools or methods. There is also disagreement on the usability of certain devices for non-expert users.

Contextual Notes

Participants highlight limitations in the original poster's knowledge of microcontrollers, communication protocols, and signal characteristics, which may affect the design and functionality of the test rig.

Who May Find This Useful

Undergraduate engineering students, hobbyists working with environmental sensors, and professionals involved in QA/QC testing of electronic devices may find this discussion relevant.

  • #31
adamaero said:
All I can find on the Q4 datalogger are instruction manuals, not datasheets.
Does it specify SPI datarates anywhere? Sorry if you already posted it and I missed it.
 
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  • #32
berkeman said:
Does it specify SPI datarates anywhere? Sorry if you already posted it and I missed it.
"6 GPIO pins and also contains a High Speed UART, SPI bus and I2C Bus"

"Includes 2X High Speed 3.3V (5V Tolerant) TTL Serial Ports, 1X High Speed SPI Interface, 1X I2C Interface with onboard pullups, 8X GPIO Pins"

I can ask the company for a numerical value.
  1. Is "high speed" is a specific value?
  2. Also, why SPI? Is this one SPI? Why isn't it UART?
  • GPIO5/UART2_RX/SPI_IN
 
  • #33
Yeah, asking the manufacturer might be a good idea, and also ask if there are any back-termination resistors included on their high-speed communication lines.
 
  • #34
Designing from the top, down;
After building a data logger you can plug in your 'test unit' to monitor functionality and QC.
In the field you can connect your 'test unit' to diagnose faults that may be present.

You will need to tap into each data logger's circuits in a number of places to check operation. That must be done without disturbing the unit under test. You could insert an extra plug&socket tap as a wedge between existing mated connectors. That would not be convenient with screw terminals.

The alternative would be to provide a standard external field test connector that gives access to the majority of internal connections on all the data loggers built. Your test unit can then evolve as further tests are developed during the manufacturing and testing phases.
 
  • #35
Baluncore said:
Designing from the top, down;
After building a data logger you can plug in your 'test unit' to monitor functionality and QC.
...
Yes, that's the easy part.

berkeman said:
... communication lines.
It's only a few feet. The site is remote, but powered by solar panels. Transmission line effects are negligible.
 

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