HITACHI AGM Series Modules: AGM-OD 33016138-3 Analog Output Module —

Technical Dossier

Product Details And Specifications

HITACHI AGM Series: Comprehensive Module Range and Technical Overview

The HITACHI AGM Series represents a core component family within Hitachi's HIZAC EH-series distributed control and programmable logic controller architecture. Deployed extensively across global heavy industry — including petrochemical complexes, nuclear power auxiliary systems, steel rolling mills, and offshore refinery platforms — the AGM series provides the analog signal conditioning backbone for process-critical control loops. Its modular backplane architecture allows integration into both standalone PLC racks and multi-drop DCS configurations, making it one of the most widely installed Hitachi I/O families in Asia-Pacific and Middle Eastern industrial facilities built between the 1990s and 2010s.

The Evolution of AGM Series Architecture

The AGM series was introduced as part of Hitachi's second-generation HIZAC EH modular control platform, succeeding the earlier H-series fixed I/O controllers. Early AGM modules operated on a parallel backplane bus with 5V TTL logic levels and required dedicated rack power supplies rated at 5VDC/3A. Mid-generation revisions introduced optically isolated analog front-ends, improving common-mode rejection ratios (CMRR) to >80dB and enabling direct connection to 4–20mA transmitter loops without external signal conditioners.

Later AGM variants incorporated surface-mount component technology, reducing board-level failure rates and extending MTBF ratings. Compatibility across AGM generations is constrained by backplane connector pinout revisions — AGM modules with suffix -3 and -4 are generally cross-compatible within EH-150 and EH-300 rack families, while earlier suffix -1 and -2 variants require verification against rack revision documentation. As of 2020, Hitachi has formally discontinued new production of the AGM series, transitioning customers toward the EH-RIO remote I/O platform and the newer H-8000 series DCS. This places the entire AGM catalog in end-of-life (EOL) status, making third-party spare parts sourcing the primary maintenance pathway for installed base operators.

AGM Series Full Catalog & Functionalities (SKU List)

Analog Output Modules

• AGM-OD 33016138-3: 4-channel 4–20mA analog output, 12-bit resolution, EH-150/300 rack compatible
• AGM-OD 33016138-4: 4-channel analog output, revised isolation, drop-in replacement for -3 suffix
• AGM-OD 33016140-1: 8-channel 4–20mA analog output module, high-density rack format
• AGM-OD 33016140-2: 8-channel analog output, extended temperature range (-10°C to +60°C)

Analog Input Modules

• AGM-ID 33016130-3: 4-channel 4–20mA analog input, 12-bit ADC, optically isolated
• AGM-ID 33016130-4: 4-channel analog input, revised front-end filter, compatible with thermocouple adapters
• AGM-ID 33016132-1: 8-channel analog input, multiplexed ADC architecture, EH-300 rack
• AGM-ID 33016132-2: 8-channel analog input, enhanced EMI shielding variant
• AGM-ID 33016134-1: 4-channel high-speed analog input, 14-bit resolution, for fast-loop PID

Digital Input Modules

• AGM-DI 33016100-3: 16-point 24VDC digital input, sink type, standard rack mount
• AGM-DI 33016100-4: 16-point 24VDC digital input, source type, revised optical isolation
• AGM-DI 33016102-1: 32-point 24VDC digital input, high-density, EH-300 only

Digital Output Modules

• AGM-DO 33016110-3: 16-point 24VDC transistor output, 0.5A per point, sink type
• AGM-DO 33016110-4: 16-point 24VDC transistor output, source type, revised driver IC
• AGM-DO 33016112-1: 32-point 24VDC transistor output, high-density format

Communication & CPU Modules

• AGM-CPU 33016200-2: Central processing unit for EH-150 rack, 256KB program memory
• AGM-NET 33016210-1: H-Link network adapter, peer-to-peer rack communication
• AGM-PSU 33016300-1: 24VDC rack power supply module, 5A rated output

Sourcing Hard-to-Find & Obsolete AGM Series Parts

With Hitachi's formal EOL declaration on the AGM series, OEM new-stock availability has ceased through standard distribution channels. DriveKNMS maintains a dedicated inventory of tested AGM series modules sourced from decommissioned plant equipment, controlled factory overstock, and verified secondary market channels. All units are cataloged by part number suffix to ensure rack-revision compatibility before dispatch.

For operators running extended plant lifecycles — common in nuclear auxiliary systems and continuous-process chemical facilities where control system replacement projects span 5–15 years — DriveKNMS provides lifecycle extension support including: board-level component repair for common failure modes (DAC chip degradation, optocoupler aging, electrolytic capacitor replacement), functional equivalency assessment for cross-series substitution, and documented test reports for each refurbished unit.

Procurement teams managing AGM spare parts budgets are advised to consolidate multi-year requirements into single purchase orders where possible, as secondary market availability for specific suffix variants (particularly -3 and -4 suffixes) is declining year-on-year.

Quality Control for the AGM Series Range

AGM series modules present specific test challenges due to their parallel backplane bus architecture and mixed analog/digital signal paths on a single PCB. DriveKNMS applies the following test protocol to all AGM units prior to shipment:

• Backplane Interface Verification: Each module is seated in a reference EH-150 or EH-300 rack and subjected to full bus communication handshake testing using a Hitachi EH-CPU reference controller.
• Analog Channel Calibration: All analog output channels are verified against a calibrated 4–20mA loop tester. Output linearity is confirmed across 0%, 25%, 50%, 75%, and 100% of span. Deviation tolerance: ±0.1% of full scale.
• Isolation Resistance Test: Channel-to-channel and channel-to-backplane isolation is measured at 500VDC. Minimum acceptable: 10MΩ.
• Thermal Soak: Units are operated at 50°C ambient for 2 hours to screen for latent component failures.
• Visual & Component Inspection: PCB is inspected under 10× magnification for corrosion, cold solder joints, and capacitor bulge.

Test records are retained for 3 years and available upon request for quality-audited procurement processes.