DS3800XTIA | 8-Channel Pulse Accumulator Board

Description

Product Introduction

The DS3800XTIA is the high-speed counter board in GE’s Mark VIe line—the one that does more than just measure frequency. The “TI” designation indicates a Timer/Counter board, and the “A” suffix is the enhanced revision with a faster 100 kHz count rate and 32-bit accumulators. Unlike the frequency boards (XTFP/XTFS/XTFT) which measure frequency and period, the XTIA is designed for totalization—counting pulses over a user-defined gate time, accumulating them in 32-bit registers, and reporting the total count to the controller.

You’ll find this board in applications where totalized counts matter more than instantaneous frequency: flow totalization (pulses per gallon, accumulated over a shift or batch), position feedback (encoder counts for valve stroke), or event counting (number of starts, trips, or cycles). The 100 kHz count rate handles high-speed encoders and pulse generators, while the 32-bit accumulators can totalize for hours without overflow. The board also includes programmable gate times (from 1ms to 10 seconds) so you can balance resolution against update rate. Typical users are plant engineers doing flow totalization, valve position monitoring, or predictive maintenance based on cycle counting.

Key Technical Specifications

Compatible Replacement Models

Frequently Asked Questions (FAQ)

Q: Can I hot-swap this board?

No. The Mark VIe backplane does not support live insertion. Power down the entire I/O pack before removal. The counter registers can corrupt if you hot-plug.

Q: How is the XTIA different from the XTFP/XTFS/XTFT?

The frequency boards (XTFP/XTFS/XTFT) are optimized for measuring frequency (Hz) and period (µs) with fixed gate times. The XTIA is optimized for totalization—counting pulses over a user-programmable gate time and storing the accumulated value in a 32-bit register.

In practice:

• Frequency board: Measures “what is the frequency right now?” and updates every 100ms.
• Counter board: Measures “how many pulses have I counted in the last 10 seconds?” and reports the total count.

The XTIA can also measure frequency (by dividing the count by the gate time), but its strength is totalization.

Q: What’s a “gate time” and why does it matter?

The gate time is the period over which the board counts pulses. For example:

• Gate time = 1 second: The board counts pulses for 1 second, then reports the total count. The frequency is Count / 1 second.
• Gate time = 100 ms: The board counts for 100ms, reports the count, and resets. Faster updates, but lower resolution at low frequencies.

You can set the gate time per channel from 1ms to 10 seconds. Longer gate times give you higher resolution at low frequencies. Shorter gate times give you faster updates for control applications.

Q: How do you test this board before shipping?

We run a 7-step test with a precision pulse generator up to 100 kHz:

• Visual inspection: Check for cracked connectors, burnt traces, swollen capacitors.
• ESD check: Insulation resistance between channels and chassis ground >10MΩ.
• Power-up: Apply +5V DC, measure current draw (1.5A ±10%).
• Communication handshake: Simulate backplane connection, verify board ID.
• Counter accuracy test: Inject 1 million pulses at 100 kHz (10 seconds). Verify the board counts exactly 1,000,000 ±0.01%.
• Gate time accuracy test: Set gate time to 1 second, inject 10 kHz, verify count is 10,000 ±0.01%.
• 24-hour soak: Run at 50°C ambient with all channels counting at 10 kHz. Log counter values every hour—failure threshold is >0.01% deviation.

We reject about 3% of these boards—the counter logic is solid, but we occasionally see gate time drift.

Q: What’s the most common failure on this board?

Three things:

• Gate time drift: The internal timer that controls the gate time can drift with temperature. We recalibrate during refurbishment.
• Optocoupler burnout: The input optocouplers can fail if subjected to over-voltage. We replace them on about 10% of refurbished units.
• Counter register corruption: If power is interrupted during a count cycle, the register can freeze. We test by power-cycling during active counting.

Q: What’s the maximum count I can accumulate?

32 bits = 4,294,967,295 counts. At 100 kHz, that’s:

• 42,949.67 seconds = 11.93 hours of counting before overflow.

For most applications, you’ll reset the counter before it overflows. If you need longer totalization, you can use software rollover handling.

Q: Can I use this board for position feedback?

Yes. The XTIA counts encoder pulses to measure valve position, actuator stroke, or conveyor position. The 100 kHz count rate handles most incremental encoders (typically 50 kHz or less). The 32-bit accumulator lets you track position over a wide range.

Q: What’s the difference between the XTIA and the XTI?

The XTI has 16-bit counters (65,535 max count). At 100 kHz, that’s 0.655 seconds before overflow—not very useful. The XTIA has 32-bit counters (4.29 billion counts), making it suitable for real-world totalization.

Q: Are there counterfeit versions of this board?

Yes. Look for:

• Counter IC: Genuine boards use a high-speed 32-bit counter IC (typically a Texas Instruments or Xilinx part). Counterfeits use generic 16-bit counters and fake the 32-bit resolution.
• Optocouplers: Genuine high-speed optocouplers. Counterfeits use slower optocouplers that miss high-frequency pulses.
• Label: Genuine—matte finish, greenish barcode. Fakes—glossy.

We trace stock to decommissioned assets. If buying elsewhere, demand photos of the component side and serial sticker.

Q: What’s your warranty?

1-year against functional defects. For counter boards, we guarantee the counter accuracy for the warranty period—if it drifts out of spec, we’ll recalibrate or replace it.

Q: What’s the lead time?

We typically carry 2-4 units. Orders before 2 PM EST ship within 1-2 business days after testing. The 24-hour soak is mandatory—we won’t skip it. Expedited shipping available with waiver. For totalization applications, we recommend waiting for the full test cycle—the gate time timer only shows drift after hours of operation.

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