Description
Key Technical Parameters
| Parameter | Specification |
|---|---|
| Manufacturer | General Electric (GE) |
| Series | Mark V (Speedtronic) |
| Full Model | DS3800NGRA |
| Power Supply | +5V DC @ 3.2A, +15V DC @ 0.5A, -15V DC @ 0.3A (via backplane) |
| Temperature Inputs | 8 differential thermocouple channels (Type J/K/T, 12-bit ADC, ±2°C accuracy) |
| RTD Inputs | None |
| Fan Outputs | 8 mechanical relays, 5A continuous @ 115VAC or 30VDC (surge 10A for 100ms) |
| Tachometer Inputs | None |
| Communication | Mark V proprietary parallel backplane bus |
| Operating Temperature | 0°C to +60°C |
| Storage Temperature | -40°C to +85°C |
| LED Indicators | Power (green), Fan Run (8x amber), Over-Temp Alarm (red), Backplane Active (yellow) |
Advantages and Distinctive Features
-
5A Mechanical Relay Outputs: The DS3800NGRA delivers 5A continuous output capability (10A surge), making it suitable for driving 1/2 HP AC fans or multiple DC fans in parallel—a significant upgrade over 3A relay boards.
-
Full 8 Thermocouple Inputs: Comprehensive zone-by-zone temperature monitoring for large cabinets.
-
AC/DC Output Capability: Can switch both AC and DC fan loads, offering flexibility for mixed cabinet installations.
-
High Surge Current Handling: Mechanical relays handle 10A surges, suitable for fan motors with high startup currents.
-
Complete Galvanic Isolation: Relay outputs provide 2500V isolation between control logic and fan power circuits.
-
Simple, CPU-Dependent Operation: No onboard setpoint storage—keeps the board cost-effective and easy to troubleshoot.
Typical Application Fields
-
Turbine Cabinets with Large AC Fans: Where 5A relay capacity is required for 1/2 HP blowers or multiple fans per channel.
-
Climate-Controlled Indoor Installations: 0°C to +60°C range supports standard power plant environments.
-
High-Surge Fan Applications: Mechanical relays handle startup surges better than solid-state alternatives.
-
Budget-Conscious Relay-Based Applications: Cost-effective solution for higher-current fan control without tachometer feedback.
-
Retrofit from 3A Relay Boards: Upgrading to the DS3800NGRA for increased current capacity.
Comparison with Related Models
| Feature | DS3800NGRA | DS3800NGDC | DS3800NFEE | DS3800NFLA |
|---|---|---|---|---|
| Output Type | Mechanical relay | Mechanical relay | Mechanical relay | Mechanical relay |
| Output Current | 5A | 3A | 3A | 3A |
| Thermocouple Inputs | 8 channels | 8 channels | 8 channels | 8 channels |
| Tachometer Inputs | None | None | None | 2 channels |
| ADC Resolution | 12-bit (±2°C) | 12-bit (±2°C) | 12-bit (±2°C) | 12-bit (±2°C) |
| Onboard Logic | No | No | No | No |
| AC Fan Capability | Yes | Yes | Yes | Yes |
| Operating Temp | 0°C to +60°C | 0°C to +60°C | 0°C to +60°C | 0°C to +60°C |
| Fallback Mode | Full speed (100%) | Full speed (100%) | Full speed (100%) | Full speed (100%) |
| Cost (Used) | Medium | Low | Low | Medium |
Selection Recommendations
-
Choose the DS3800NGRA if:
-
Your fans require mechanical relay outputs with 5A continuous rating (e.g., 1/2 HP AC fans).
-
You do not require tachometer speed feedback.
-
Your cabinet requires 8 temperature sensors for comprehensive monitoring.
-
You have a climate-controlled environment (0°C to +60°C).
-
The Mark V CPU handles all control logic.
-
You need higher current capacity than 3A relay boards but do not need tachometer feedback.
-
-
Choose the DS3800NGDC or DS3800NFEE if: You need 3A relay outputs and do not require tachometer feedback.
-
Choose the DS3800NFLA if: You need relay outputs with tachometer feedback (3A only).
Critical Precautions
-
ESD Protection: The DS3800NGRA contains sensitive ADC components. Always wear a grounded ESD wrist strap.
-
Relay Contact Wear: Mechanical relays are rated for 100,000 operations at 5A. For frequent cycling applications, consider derating or using solid-state alternatives.
-
Inductive Load Derating: The 5A rating applies to resistive loads. For inductive fan motors, derate to 3.5A or use an external RC snubber across each relay output.
-
No Tachometer Inputs: The DS3800NGRA has no tachometer capability. Do not connect speed sensors.
-
No Hot-Swap: Always depower the Mark V rack before inserting or removing the DS3800NGRA.
-
Slot Assignment: Install in auxiliary I/O slots (typically slots 8–10). Do not install in CPU or analog input slots.
-
CPU Dependency: Since the DS3800NGRA has no onboard logic, the Mark V CPU must send fan ON/OFF commands. If backplane communication is lost, the board defaults to 100% fan speed (fallback mode). Address communication issues promptly.
-
Firmware Compatibility: The DS3800NGRA is compatible with all Mark V CPU firmware versions (v3.x and above). No specific CPU upgrade is needed.
A-B 802TA2P
A-B 1762-OW8
UDIAN AI-7021
Reviews
There are no reviews yet.