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TMC series: FAQ and Troubleshooting guide

This document provides answers to frequently asked questions and troubleshooting guidance for Dracal TMC (thermocouple reader) products, including the TMC100 and TMC200 series. The FAQ section covers general product information, while the troubleshooting section offers step-by-step diagnostic procedures for resolving common issues.

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Frequently Asked Questions

Troubleshooting

Frequently Asked Questions

What are the main differences between the various TMC models?

The TMC100 series offers USB thermocouple adapters with good resolution (0.0625 °C) and average sampling rate (3 samples per second).The TMC200 series includes USB adapters for thermocouples offering excellent resolution (0.00005 °C) and a higher sampling rate (5 samples per second). In addition, the TMC200 returns meaningful error codes such as “Sensor out of Range” or “Probe Disconnected,” for example. Finally, an adjustment is made at 0 °C during production to compensate for zero error and improve accuracy.

Can the probes be submerged in water?

Bare wire thermocouple probes cannot be immersed in water, but those with FEP insulation can. As for the TMC adapter itself, it must be kept dry!

Why did you choose to offer only one thermocouple probe type?

There is a wide range of thermocouple probes suitable for every conceivable application scenario. Although we do not distribute temperature probes, we still want to offer the possibility of obtaining a complete solution on our platform. That is why we have selected one bare wire probe of each type that can meet the needs of the majority of our users, and have designed a version with FEP insulation for users who use them in “potentially conductive” environments.

Can I use any probe of my choice with your adapters?

Of course! These are universal adapters. Just make sure you choose the adapter that is the same type as your thermocouple (e.g., J, K, N, E, T, etc.).

Can a thermocouple probe be used at temperatures beyond the announced operating temperature range of the TMC housing (0°C to 50°C)?

To measure temperature, only the probe should be placed in an environment with a temperature above 50°C. In addition, the accuracy specified for adapters is optimal when they are at 25°C.

How do I connect my thermocouple probe to the adapter?

A two-pin connector is included with the adapter. Simply open it and plug in the wires from your thermocouple. Then insert the connector into the USB adapter, and you’re done! It is also difficult to remove the connector from the adapter, making the construction very sturdy.

Can I have a STEP/CAD file of the purchased TMC for its dimensions?

Yes, that is possible. They are available on the product page, in the “Technical Specifications” section. Please also note that all case dimensions are listed in the product datasheet.

What calibration is performed on the instruments during production?

TMC100: Temperature conversion principles for thermocouples are applied as is. No additional compensation is performed. Accuracy remains compliant with thermocouple standards.

TMC200: Same as TMC100, with the addition of calibration at 0°C to compensate for zero error and improve accuracy.

Is the individual calibration of the measuring instruments done at the Dracal factory?

At the Dracal production facility, a pass/fail test is performed during the manufacturing of the measuring instrument. In addition, the component manufacturer performs individual calibration at its facility before shipping the components to us. These calibrations are not ISO 17025 certified, but if your industry does not require this standard, you can confidently use Dracal USB adapters as soon as you receive them. If you would like to obtain an ISO 17025 certificate for your device, you can purchase one in addition to your product on the ordering page.

Is an external probe necessary for calibrating the adapter?

No, it is not necessary to have a probe to calibrate the adapter. Without a probe, the laboratory will use an instrument that simulates the presence of a theoretical thermocouple probe.

However, in most cases, our customers choose to send the complete system, i.e., the thermocouple thermometer with the probe they intend to use, as it is the probe that contributes most to the uncertainty. Calibrating them together ensures that the combined performance meets the requirements.

Troubleshooting

Temperature readings show incorrect polarity (negative when should be positive)

This indicates a wiring issue, commonly occurring when customers wire their own thermocouple sensors. 

Solution: Verify your connections match the product’s connection diagram in the technical datasheet

Intermittent or sporadic incorrect readings

This typically results from temporary connection issues or environmental factors.

The good news is that you probably don’t have a problem with the sensor. All you need to do is improve your installation!  Indeed, most intermittent reading problems are resolved through improved connections or environmental modifications.

But of course, we can help you solve the problem. However, to save some time helping us identify the root cause, we ask our users to perform the following checks and share with us the results with their support request.

Cable Examination

  • Inspect the entire thermocouple sensor cable for damage, kinks, or excessive bending
  • Check for mechanical stress or movement during operation
  • Note if the cable passes near moving parts or high-temperature areas

Installation Environment

  • Is the setup subject to vibration (machinery, HVAC, building movement)?
  • Are there temperature fluctuations where connections are made?
  • Is there moisture or high humidity around connections?

Electrical Interference Check

  • Are motors, welders, or other electrical equipment operating nearby?
  • Do invalid readings correlate with specific equipment turning on/off?

Noise Suppression

  • Try connecting to a USB hub with external power (computer USB power can be unstable)
  • For users who have wired their thermocouples to the connector themselves: Check all wire connections and ensure screw terminals are tight
  • Look for corrosion, discoloration, or loose wires

Isolation Test

  • Connect a different thermocouple sensor to see if the problem persists
  • Try your current sensor with a different reader (if available)

Connection Stability Test

  • Monitor temperature readings while gently wiggling wires at connection points
  • Note if this triggers invalid readings

Pattern Analysis

  • Does the issue occur at specific times?
  • Is there correlation with environmental conditions or nearby equipment?

When contacting support, please provide:

  • Results from the above tests
  • System installation duration
  • Recent changes to installation or nearby equipment
  • Photos of your connection setup (if possible)

DracalView doesn’t recognize my product

This typically occurs with VCP products (product codes starting with “VCP-“) that are in VCP mode, since DracalView for Windows only communicates via USB protocol.

Solution: Switch to USB mode

Option 1 (Recommended)

  1. Download DracalView version 3.4.2 or later
  2. Use the ProtocolSwitcher tool located in C:Program FilesDracal to switch to USB mode with one click

Option 2 (Alternative method)

  1. Download and configure PuTTY following our step-by-step procedure
  2.  Enter the command PROTOCOL USB in the terminal like shown in this example
    • Note: You won’t see characters as you type – this is normal behavior

Your question or issue is not covered here?

For additional support, please do not hesitate contact our technical team. We typically answer in less than 1 business day.

Our job is to simplify your job.

 

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