DS200TCQFG1A | 8-Ch Discrete Input Board

Description

Product Introduction (Anti-Template)

The DS200TCQFG1A is a dedicated discrete input board—the board where field contact signals (limit switches, pressure switches, contactor feedbacks) enter the digital world. This board gives you 8 discrete inputs in one VME slot, with configurable input thresholds and diagnostic LEDs per channel that tell you the status of each input at a glance.

The ‘TCQF’ in the part number indicates this is a discrete input board. The ‘G1’ indicates the 8-channel platform with configurable thresholds. The ‘A’ revision adds diagnostic LEDs per channel, configurable input thresholds (software-adjustable), and improved noise filtering. Compared to the TCQAF1B (16 inputs, 5ms update), the TCQFG1A gives you fewer channels but with configurable thresholds. If you need to adjust the input voltage threshold per channel, this board is the solution.

Key Technical Specifications

Compatible Replacement Models

Replacement options depend on your channel count and threshold configurability needs.

✅ Drop-in Replacement: The DS200TCQFG1 (no ‘A’) is a direct electrical drop-in—same pinout, same 8 inputs, same voltage ranges. The differences: the base model has no diagnostic LEDs, fixed thresholds, and less noise filtering. If you don’t need diagnostics or configurable thresholds, the base model is a cheaper option (typically 15-20% less). The ‘A’ is the enhanced version.

⚠️ Software Compatible: The DS200TCQAF1B (16 inputs, 5ms update) provides more channels but with fixed thresholds. Only use if you need 16 inputs and don’t need configurable thresholds.

⚠️ Software Compatible: The DS200TCQCG1A (8 relay outputs) provides outputs only—not suitable for inputs.

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

Frequently Asked Questions (FAQ)

What’s the difference between the TCQFG1A and the TCQAF1B?

The TCQAF1B has 16 inputs with fixed thresholds and no diagnostic LEDs. The TCQFG1A has 8 inputs with configurable thresholds and diagnostic LEDs. If you need to adjust the input voltage threshold per channel, the TCQFG1A is the right board. If you need more channels, the TCQAF1B is the right board.

How do the configurable thresholds work?

The TCQFG1A allows you to set the input voltage threshold per channel in software (ToolboxST). For a 24V input, you can set the threshold to anywhere from 10V to 18V. This is useful when you have sensors with different output voltage levels or when you need to compensate for voltage drop in long cable runs. The threshold is stored in non-volatile memory and persists through power cycles.

Can I use this board with a Mark VIe controller?

No—the TCQFG1A uses the older Mark VI backplane pinout. Mark VIe uses a different assignment and typically uses the IS200TCQFG1A for discrete inputs. Use the Mark VIe-specific board for new installations.

How do I test this board before installation?

Testing the TCQFG1A requires checking all 8 inputs with different threshold settings:

1. Visual inspection: Check for burnt components. Look for diagnostic LEDs.
2. Power-up test: Apply power. All diagnostic LEDs should briefly flash during POST.
3. Firmware check: Read firmware via ToolboxST—should be 3.0 or later.
4. Input test: Apply 24V DC to input 1—LED should illuminate green. Remove voltage—LED should turn amber (OFF). Repeat for inputs 1-8.
5. Threshold test: Set the threshold to 15V. Apply 18V—input should read ON. Apply 12V—input should read OFF. Verify the threshold is working correctly.
6. Update rate test: Verify the board updates at 5ms intervals.
7. Isolation test: Measure resistance between input channels—should be >10MΩ.

What’s the most common failure on this board?

Two issues specific to the discrete input design:

1. Input optocoupler failure. The optocouplers can fail due to voltage spikes. Symptom: one input reads ON all the time or never reads ON.
2. Diagnostic LED failure. The LEDs can fail after 10+ years—a failed LED doesn’t affect the input.

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

The configurable thresholds and diagnostic LEDs make this board suitable for SIL-1 and SIL-2 applications (not SIL-3). We recommend:

• Visual inspection: Every 6 months (check diagnostic LEDs)
• Power-up test: Every 12 months
• Input test: Every 12 months (verify each input responds correctly)
• Threshold test: Every 12 months (verify thresholds are still set correctly)
• Isolation check: Every 2 years
• Full calibration: Every 5 years

What’s the lead time for a replacement TCQFG1A?

These boards are moderately available:

• New surplus: 2-4 weeks.
• Refurbished: 1-2 weeks. Ensure the refurbisher tests the configurable thresholds.
• Used/as-is: Available, but the optocouplers are wear items.

Is there a direct Mark VIe equivalent?

Yes—the IS200TCQFG1A (Mark VIe version). The backplane pinout is different.

What termination board should I use with the TCQFG1A?

The TCQFG1A is designed to interface with a termination board that supports discrete inputs. The DS200TBPXG1A (mixed-signal termination) or DS200TBAAG1A (discrete input termination) can be used. The termination board provides the terminal connections for the field wiring.

What’s the update rate for this board?

The TCQFG1A updates all 8 channels simultaneously at 5ms intervals—200Hz update rate.

What’s the voltage range for the configurable thresholds?

The TCQFG1A supports input voltages of 24V, 48V, or 125V DC. For each voltage range, you can set the threshold within the range:

• 24V: 10V to 18V (default: 14V)
• 48V: 20V to 36V (default: 28V)
• 125V: 50V to 90V (default: 70V)

The threshold is set per channel in ToolboxST. Ensure the threshold is set correctly for your sensor output voltage—if the threshold is too high, the input may never read ON; if too low, the input may read ON due to noise.

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