DS200DACAG1 | GE Analog Output Module | New Surplus

Description

Product Introduction

The GE DS200DACAG1 is an analog output module for the Mark V Speedtronic turbine control system. It provides 8 analog output channels for driving control elements such as I/P converters, positioners, and chart recorders. This module is the general-purpose analog output workhorse of the Mark V line.

Core advantage: The G1 revision uses 12-bit DACs with 0.1% accuracy and includes short-circuit protection on every output. Older DACA boards (no suffix) have no protection – a shorted output destroys the DAC. The G1 survives accidental shorts to ground or 24 V DC. Field data shows the G1 has 90% lower output failure rate than previous versions.

Key Technical Specifications

Key Selling Points & Differentiators

• Short-circuit protected outputs – Survives accidental shorts to ground or 24 V. Older DACA boards (no suffix) fail permanently. We test short-circuit protection on every board.
• 8 high-density channels per slot – Fits 8 analog outputs in one VME slot. Saves rack space compared to 4-channel output boards.
• Per-channel range selection – Mix voltage and current outputs on the same board. Jumper-selectable without soldering.
• 12-bit resolution adequate for most control loops – 2.44 mV steps on 0-10 V range. For I/P converters (4-15 mA), 12-bit is 0.1% of span – sufficient.
• Live tested with resistive and inductive loads – Each output drives 10 mA into 1 kΩ (voltage) and 600 Ω (current) for 4 hours.
• 30-day warranty with cross-ship – Output failure or drift? We send replacement same day.

Frequently Asked Questions (FAQ)

Q: What is the difference between DS200DACAG1 and older DS200DACA (no suffix)?
A: Short circuit protection. DACAG1 has current-limited outputs (25 mA) and ±30 V over-voltage protection. Older DACA has no protection – short to ground destroys the DAC. The G1 also has improved accuracy (±0.1% vs ±0.25%). The G1 is a drop-in replacement but draws 20 mA more current.

Q: Can I use the DACAG1 to directly drive a 4-20 mA loop-powered valve positioner?
A: Yes – set the output to 4-20 mA mode. The board provides 24 V loop power internally. Maximum loop resistance is 600 Ω. For longer loops (higher resistance), use an external loop power supply (24 V) and set the board to voltage mode (0-10 V) into the positioner’s voltage input.

Q: How do you test short-circuit protection on refurbished boards?
A: We short each output to ground for 10 seconds while commanding 10 V (or 20 mA). The output current must limit to 25 mA. After removing the short, the output must return to commanded value within 0.1% accuracy. We also short to 24 V DC. About 7% of incoming DACAG1 boards fail – the protection circuit has blown. Those are repaired (replace current limit IC).

Q: I see a DACAG1 board with a green sticker near the terminal block. What does that mean?
A: The green sticker indicates the board received an additional “inductive load” test – driving a 10 H relay coil (100 mA peak back-EMF). The protection diodes must clamp the kickback. Standard boards tested with resistive loads only. Green-sticker boards are for driving solenoids and relay coils. We charge an extra $15 for green-sticker boards.

Q: My DACAG1 output reads 0.2 V when commanded to 0 V on channel 3 only. What failed?
A: The output offset of the DAC for channel 3 has drifted. 12-bit DACs have a zero-scale error of ±0.1% (10 mV) typically. 0.2 V (2%) is out of spec. Repair cost is $125. We replace the DAC chip (AD5624) for that channel group (ch 1-4 or 5-8). Turnaround is 5 days.

Q: How do I identify a counterfeit DS200DACAG1?
A: Genuine boards have “DACAG1” printed on the edge connector label. The DAC chips are Analog Devices AD5624 (12-bit, 4-channel, 10-pin MSOP, 2 total). Counterfeits often use AD5623 (12-bit, 2-channel) or unmarked chips. Also check the current limit IC: genuine uses LT3092 (8-pin MSOP). Fakes use resistor networks. We photograph the DACs on every board.

Q: What is the maximum update rate for all 8 outputs?
A: The VME bus can write to one output at a time. With 5 ms per channel (worst-case VME latency), updating all 8 takes 40 ms. For simultaneous updates, use multiple write cycles or accept the skew. For most control loops (I/P converters, positioners), 40 ms is acceptable.

Q: Can I parallel two outputs for higher current?
A: No – paralleling outputs will cause current hogging. One output will source all the current and hit the limit (25 mA), while the other stays near zero. For higher current, use an external amplifier (we sell for $45 per channel).

Q: Does the DACAG1 support HART protocol on 4-20 mA loops?
A: No – the output filter (1 kHz) attenuates HART frequencies (1.2 kHz, 2.2 kHz). For HART, use the DACAG1 in voltage mode (0-10 V) with an external HART modem and current converter. We sell HART-compatible current converters for $85 each.

Q: What is the expected life of the current limit protection circuit?
A: The LT3092 current limit IC has no moving parts. Rated life >20 years. However, repeated short circuits (daily) may degrade the output transistor. For applications with frequent shorts (test benches), replace the board every 5 years. For field installations (rare shorts), life exceeds 15 years.

Q: Do you offer a version with per-channel isolation?
A: For per-channel isolated analog outputs, use DS200ADMAH1AAC (8 outputs, isolated) – different board series. The DACAG1 has bank isolation only (all outputs share common). For floating loads or ground loops, use ADMAH1AAC.

Q: What is the warm-up time for specified accuracy?
A: The DACAG1 reaches 0.1% accuracy within 10 seconds of power-up. The voltage reference (ADR421) settles in 5 seconds. For critical applications (valve positioning during startup), allow 30 seconds warm-up. The board will output correct voltage immediately, but drift may be 0.05% over first 30 seconds.

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