DS200TCTSG1 | GE Mark VI Input Board

Description

Product Introduction (Anti-Template)

The DS200TCTSG1 is a high-density thermocouple input board with a shared CJC design—the board that converts thermocouple signals (J, K, T, E, N) into temperature values for turbine monitoring. This board gives you 16 thermocouple inputs in one VME slot, with a single shared cold junction compensation sensor and 14-bit resolution.

The ‘TCTS’ in the part number indicates this is a thermocouple input board with shared CJC. The base model has 16 inputs, a single shared CJC sensor, 14-bit resolution, ±0.7°C accuracy, and a 20ms update rate. The board is designed for applications where you need many thermocouple inputs in a single slot and where the shared CJC limitation is acceptable—like monitoring multiple bearing temperatures or process temperatures on a large turbine skid.

Key Technical Specifications

Compatible Replacement Models

Replacement options depend on your CJC requirements and accuracy needs.

✅ Drop-in Replacement: The DS200TCTSG1A (if available) would be the ‘A’ revision. As of this writing, the base model is the only version. Always verify the specific suffix before ordering.

⚠️ Software Compatible: The DS200TCTEG1A (16 inputs, per-channel CJC, 16-bit, ±0.4°C accuracy) provides better accuracy and per-channel CJC. Only use if you need better accuracy.

⚠️ Software Compatible: The DS200TCCBG2A (16 inputs, shared CJC, 14-bit, ±0.7°C accuracy) provides similar features with shared CJC. Only use if you need 16 channels.

❌ Hardware Incompatible: Any general-purpose analog input board (TCCAG1 series) uses different backplane pins and is not suitable for thermocouple signals.

Frequently Asked Questions (FAQ)

What’s the difference between shared CJC and per-channel CJC?

Shared CJC (TCTSG1) uses a single CJC sensor for all 16 thermocouple inputs. This assumes the termination board is isothermal (same temperature across all terminals). Per-channel CJC (TCTEG1A) uses individual CJC sensors per channel, eliminating the error from temperature gradients across the termination board. Shared CJC is cheaper but less accurate—if there’s a temperature gradient, the error can be 1-2°C.

Why doesn’t this board support R, S, or B thermocouples?

The TCTSG1 uses a 14-bit ADC that doesn’t have the dynamic range to accurately measure R, S, and B thermocouples (used for high-temperature measurements above 1000°C). The board is designed for general-purpose temperature monitoring (J, K, T, E, N), not for high-temperature exhaust measurements.

Can I use this board with a Mark VIe controller?

No—the TCTSG1 uses the older Mark VI backplane pinout. Mark VIe uses a different assignment and typically uses the IS200TCTSG1 for thermocouple inputs. Use the Mark VIe-specific board for new installations.

How do I test this board before installation?

Testing the TCTSG1 requires checking all 16 channels:

1. Visual inspection: Check for burnt components.
2. Power-up test: Apply power. The board’s status LED (green) should illuminate within 2 seconds.
3. Firmware check: Read firmware via ToolboxST—should be 2.0 or later.
4. CJC test: With no thermocouple connected, read the CJC temperature—should match ambient within ±1°C.
5. Input test: Apply 10.00mV to input 1—read 250°C ± 0.7°C. Repeat for inputs 1-16.
6. Isolation test: Measure resistance between input channels—should be >10MΩ.

What’s the most common failure on this board?

Two issues specific to the thermocouple input design:

1. CJC sensor drift. The single shared CJC sensor can drift over time—symptom: a consistent offset on all channels.
2. Input amplifier failure. The high-impedance input amplifiers can fail due to ESD or overvoltage.

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

The shared CJC design makes this board suitable for SIL-1 applications (not SIL-2 or SIL-3). We recommend:

• Visual inspection: Every 6 months
• Power-up test: Every 12 months
• CJC test: Every 12 months
• Input accuracy check: Every 12 months (0.7°C spec)
• Isolation check: Every 2 years
• Full calibration: Every 5 years

What’s the lead time for a replacement TCTSG1?

These boards are moderately available:

• New surplus: 2-4 weeks.
• Refurbished: 1-2 weeks. Ensure the refurbisher tests all 16 channels.
• Used/as-is: Available, but the CJC sensor is a wear item.

Is there a direct Mark VIe equivalent?

Yes—the IS200TCTSG1 (Mark VIe version). The backplane pinout is different.

What termination board should I use with the TCTSG1?

The TCTSG1 is designed to interface with the DS200TBCSG1 (thermocouple termination board with shared CJC). The termination board provides the CJC sensor and the terminal connections. The TCTSG1 is the active board that reads the signals.

What’s the update rate for this board?

The TCTSG1 samples all 16 channels simultaneously at 20ms intervals—50Hz update rate.

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

GE recommends a maximum of 250 feet (75 meters) for thermocouple cable runs. The limiting factor is the resistance of the thermocouple wire and the input impedance of the board (>5MΩ). For critical temperature measurements, keep cable runs as short as possible. The shared CJC design assumes the termination board is isothermal—keep the termination board away from heat sources.

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