DS200TCCBG1B | 8-Ch Thermocouple Board

Description

Product Introduction (Anti-Template)

The DS200TCCBG1B is the mid-tier thermocouple board that hits the sweet spot between cost and capability. It takes the solid thermocouple measurement of the ‘A’ revision and adds programmable digital filtering—the feature that makes turbine hall noise manageable—without the premium price of the ultra-precision ‘ANE’ version.

The ‘B’ revision brings three key improvements over the ‘A’: digital filtering (50Hz, 60Hz, 250Hz cutoff) that pushes common-mode rejection to 100dB, improved accuracy from 0.5°C to 0.4°C, and a slightly faster update rate (40ms vs. 50ms). Compared to the TCCBG1A, the ‘B’ is about 15-20% more expensive but gives you much better noise rejection for turbine applications where VFDs and large motors are everywhere. It’s the board you choose when you need good accuracy and good noise immunity but don’t need the absolute best accuracy of the ‘ANE’ or the extended temperature range of the ‘ALD’.

Key Technical Specifications

Compatible Replacement Models

Replacement options depend on your noise environment and accuracy requirements.

✅ Drop-in Replacement: The DS200TCCBG1A (no ‘B’) is a direct electrical drop-in—same pinout, same 8 channels, same ±100mV range. The differences: the ‘A’ has no digital filtering, ±0.5°C accuracy, and a slower update rate (50ms vs. 40ms). If your plant is electrically quiet and your accuracy requirements are modest, the ‘A’ is a cheaper option (typically 15-20% less). If you have VFDs or other noise sources, the ‘B’ is worth the premium.

✅ Drop-in Replacement: The DS200TCCBG1ALD (0.3°C accuracy, reinforced isolation) is also electrically identical—but much more expensive. Only if you need reinforced isolation and the best accuracy.

⚠️ Software Compatible: The DS200TCCAG1A (general-purpose analog) fits the rack but cannot handle thermocouple-level signals—you’d need external transmitters. Not recommended.

❌ Hardware Incompatible: Any discrete I/O board (TCCX series) uses different backplane pins and is not suitable for thermocouple inputs.

Frequently Asked Questions (FAQ)

What’s the difference between the TCCBG1B and the TCCBG1A?

The ‘B’ revision adds three improvements:

• Digital filtering: Programmable 50Hz, 60Hz, or 250Hz cutoff—reduces power-line noise and VFD harmonics. The ‘A’ version has no digital filtering.
• Better accuracy: ±0.4°C vs. ±0.5°C full scale, and improved temperature drift (15ppm/°C vs. 20ppm/°C).
• Faster update rate: 40ms vs. 50ms—faster response for temperature control loops.

The digital filtering is the key improvement—it makes the thermocouple board usable in real-world turbine environments where 60Hz noise is everywhere.

How does the digital filtering work on the ‘B’ revision?

The TCCBG1B uses a programmable digital filter that you configure in ToolboxST. The filter is a finite impulse response (FIR) filter with selectable cutoff frequencies: 50Hz, 60Hz, or 250Hz. The 50Hz and 60Hz settings are notch filters that remove power-line frequency noise and its harmonics. The 250Hz setting gives you a wider bandwidth (faster response) with less filtering. The filter adds a delay: about 5ms at 60Hz, 6ms at 50Hz, and 2ms at 250Hz. The delay is consistent and predictable—you can account for it in your control loops if needed.

Can I use this board with a Mark VIe controller?

No—the TCCBG1B uses the older Mark VI backplane pinout. Mark VIe uses a different assignment and typically uses the IS200TCCBG1B for thermocouple inputs. Use the Mark VIe-specific board for new installations.

How do I test this board before installation?

Testing the ‘B’ revision requires checking the digital filtering functionality:

1. Visual inspection: Check for burnt or discolored components. Look for cracked solder joints on the backplane connector. The ‘B’ has an additional IC (the filter chip) compared to the ‘A’.
2. Power-up test: Install the board in a test rack and apply 24 VDC. The board’s status LED (green) should illuminate within 2 seconds.
3. Firmware check: Read the firmware version via ToolboxST—should be 3.0 or later.
4. CJC test: With no thermocouple connected, read the CJC temperature for each channel. It should match ambient within ±0.15°C.
5. Input test – accuracy: Apply a precision 10.00mV DC (equivalent to about 250°C on Type K) to channel 1. The read value should match the expected temperature ±0.4°C. Repeat for channels 1-8.
6. Filter test: Inject a 60Hz AC signal (1mV amplitude) on top of a 5mV DC signal into channel 1. Enable the 60Hz digital filter. The read value should show the DC component with the noise reduced to less than 0.05mV (1% of the input signal). Disable the filter and verify the noise is visible.
7. Isolation test: Measure the resistance between an input terminal and the board’s ground—should be >10MΩ.

What’s the most common failure on the ‘B’ revision?

Two issues specific to the filtered board:

1. Digital filter chip failure. The ‘B’ revision uses a programmable filter chip (FPGA or DSP). If this chip fails, the filtering stops working, and all channels show higher noise (about 10-20 counts of noise on the raw ADC values). The symptom is fluctuating readings on all channels even with steady inputs.
2. CJC sensor drift. The CJC sensors (±0.15°C accuracy) can drift over time, causing a consistent offset on all channels. The symptom: all channels read 1-2°C high or low. The fix: recalibrate or replace the termination board.

If I’m using this board in a SIL-rated safety application, what’s the recommended maintenance interval?

For SIL-2 and SIL-3 applications (IEC 61508), we recommend:

• Visual inspection: Every 6 months
• CJC test: Every 6 months (verify CJC sensors read ambient correctly)
• Input accuracy check: Every 12 months (0.4°C spec)
• Filter test: Every 12 months (inject noise and verify the filter is working)
• Full calibration: Every 5 years

What’s the lead time for a replacement TCCBG1B?

These boards are moderately available:

• New surplus: 2-4 weeks. The ‘B’ version is the most common mid-tier thermocouple board.
• Refurbished: 1-2 weeks. Ensure the refurbisher tests the digital filter—most shops only test accuracy and skip the filter functionality.
• Used/as-is: Available but moderate risk. The filter chip is a wear item—used boards may have degraded filtering.

Is there a direct Mark VIe equivalent?

Yes—the IS200TCCBG1B (Mark VIe version). The backplane pinout is different, and the Mark VIe board may have different filtering options. If you’re migrating to Mark VIe, plan to replace all thermocouple boards as part of the rack conversion.

Which termination board should I use with the TCCBG1B?

The TCCBG1B is designed to interface with the DS200TBCBG1A (or DS200TBCBG1AAA) thermocouple termination board. The termination board provides the CJC sensors and the terminal connections. The ‘A’ termination board with per-channel CJC sensors is recommended for best accuracy. The base model DS200TBCBG1 (single CJC sensor) will work but you’ll lose the per-channel CJC accuracy.

What’s the update rate for this board?

The TCCBG1B samples all 8 channels simultaneously at 40ms intervals—25Hz update rate, faster than the ‘A’ version’s 50ms. The digital filter adds a delay (2-6ms depending on the setting), but the underlying sampling rate remains 40ms. The 40ms update rate is sufficient for most turbine temperature monitoring and control applications.

What’s the maximum cable length for thermocouples on this board?

Same as the TCCBG1A: 300 feet (100 meters). The ‘B’ revision’s better filtering allows longer cable runs in noisy environments, but the practical limit is still the resistance of the thermocouple wire. For critical temperature measurements, keep cable runs as short as possible and use shielded thermocouple cable.

Can I use this board with 125V DC?

No—the TCCBG1B is designed for 24 or 48 VDC only.

What’s the correct thermocouple wire type for this board?

The TCCBG1B supports J, K, T, E, N, R, S, and B thermocouples. The most common in turbine applications are Type K (exhaust temperature) and Type J (bearing temperature). The thermocouple type is configured in software (ToolboxST) per channel. The board performs linearization based on the selected type. For the best accuracy, use premium-grade (special limits of error) thermocouple wire. The board’s 0.4°C accuracy is wasted on standard-grade wire with ±1.1°C tolerance.

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