1. Product Overview

Product Name: EX9018-M
Model: EX9018-M
Series: EX-9000 Series Analog Input Modules
Article Number: EX9018-M
Manufacturer: ICP DAS / EX Series Industrial Automation Modules

The EX9018-M is a high-precision, 8-channel, 16-bit analog input module designed for thermocouple and low-level voltage measurement applications. It communicates via the Modbus RTU protocol over an RS-485 interface, making it suitable for distributed data acquisition and industrial process control systems. The module supports multiple thermocouple types (J, K, T, E, R, S, B, N) and can also measure differential voltage and current signals. It is part of the EX-9000 modular I/O family, known for robust performance, galvanic isolation, and flexible configuration options.

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2. Key Features

- 8 Differential Analog Input Channels: Each channel supports differential measurement for improved noise immunity and accuracy.
- 16-bit Resolution: Provides high precision for temperature and voltage measurements.
- Thermocouple Compatibility: Supports standard thermocouple types J, K, T, E, R, S, B, and N.
- Multiple Input Ranges: Configurable for ±15mV, ±50mV, ±100mV, ±500mV, ±1V, ±2.5V, or ±20mA (with external 125Ω resistor).
- Sampling Rate: 10 samples per second (10 Hz) with a bandwidth of 15.7 Hz.
- High Accuracy: ±0.1% of full scale with low drift characteristics (zero drift 0.5 μV/°C, span drift 25 ppm/°C).
- Galvanic Isolation: Input and output circuits are isolated to prevent ground loops and enhance system reliability.
- RS-485 Communication: Two-wire interface supporting baud rates from 1200 to 115200 bps.
- Modbus RTU Protocol: Fully compatible with Modbus RTU for easy integration into SCADA, PLC, and DCS systems.
- Cold Junction Compensation (CJC): Built-in compensation for accurate thermocouple temperature readings.
- Open Circuit Detection: Detects thermocouple break conditions (available on BL and 19 variants).
- Wide Power Supply Range: Operates from +10V to +30V DC.
- Dual Watchdog System: Includes both module and host watchdogs for enhanced reliability.
- EEPROM Configuration Storage: Retains settings such as address, baud rate, and input type.
- INIT* Mode: Hardware switch for resetting or reconfiguring communication parameters.
- Compact and Rugged Design: Suitable for industrial environments with wide operating temperature range.

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3. Technical Specifications

| Parameter | Specification |
|----------------|-------------------|
| Interface | RS-485, 2-wire |
| Communication Protocol | Modbus RTU |
| Baud Rates | 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200 bps |
| Analog Input Type | Differential |
| Number of Channels | 8 |
| Resolution | 16 bits |
| Input Impedance | 20 MΩ |
| Input Voltage Ranges | ±15mV, ±50mV, ±100mV, ±500mV, ±1V, ±2.5V |
| Current Input Range | ±20mA (with external 125Ω resistor) |
| Thermocouple Types | J, K, T, E, R, S, B, N |
| Sampling Rate | 10 samples/sec |
| Bandwidth | 15.7 Hz |
| Accuracy | ±0.1% of full scale |
| Zero Drift | 0.5 μV/°C |
| Span Drift | 25 ppm/°C |
| CMR (50/60Hz) | 150 dB |
| NMR (50/60Hz) | 100 dB |
| Power Supply | +10V to +30V DC |
| Isolation | Galvanic isolation between input and communication circuits |
| Warm-up Time | 30 minutes recommended |
| Operating Temperature | -25°C to +75°C (typical for EX series) |
| Storage Temperature | -40°C to +85°C |
| Humidity | 10–90% RH, non-condensing |
| Mounting | DIN-rail or panel mount |
| Dimensions / Weight | Compact modular housing (typical EX-9000 form factor, approx. 72 x 118 x 35 mm, ~200 g) |

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4. Functionality

The EX9018-M functions as an analog input acquisition module for temperature and low-level signal measurement. Each of its eight differential channels can be configured for thermocouple or voltage input. The module measures the Seebeck voltage generated by thermocouples and applies cold junction compensation to calculate accurate temperature values.

For voltage or current measurement, the module converts analog signals into digital data using a 16-bit ADC. The data is transmitted via RS-485 using Modbus RTU protocol, allowing integration with PLCs, HMIs, SCADA systems, and other Modbus-compatible devices.

Use Cases and Applications:
- Industrial temperature monitoring and control
- Process automation and data acquisition
- Laboratory instrumentation
- Energy management systems
- Environmental monitoring
- OEM equipment requiring multi-channel thermocouple input

Compatibility:
- Works with Modbus RTU masters such as PLCs, SCADA software, and industrial PCs.
- Compatible with EX-9000 configuration utilities and ASCII command interface for setup.
- Supports integration with Modbus mapping for easy register-based data access.

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5. Components & Accessories

Included Items:
- EX9018-M module
- User manual and configuration guide
- Software utility for configuration (EX-9000 Utility)

Optional Accessories:
- External 125Ω precision resistor (0.1%) for current measurement
- RS-485 communication cable
- DIN-rail mounting kit
- Power supply (10–30V DC regulated)
- Thermocouple sensors (J, K, T, E, R, S, B, N types)

Connectors:
- Screw terminal blocks for analog input channels
- RS-485 communication terminals (D+, D−)
- Power input terminals (+Vs, GND)
- INIT* switch or pin for configuration reset

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6. Installation & Setup

Requirements:
- DC power supply (10–30V DC)
- RS-485 network connection
- Modbus RTU master device or configuration PC

Mounting Options:
- DIN-rail mounting (standard)
- Panel mounting (optional)

Configuration Steps:
1. Power Connection: Connect +Vs and GND to a regulated 10–30V DC source.
2. Communication Wiring: Connect RS-485 D+ and D− lines to the network bus.
3. INIT* Mode: Use the rear INIT* switch or connect INIT* pin to GND to enter configuration mode.
4. Address and Baud Rate Setup: Default address = 01, baud rate = 9600 bps. Adjust via ASCII commands or EX-9000 utility.
5. Protocol Selection: Default protocol is Modbus RTU. Can be switched to ASCII mode if required.
6. Filter Configuration: Default 60Hz rejection filter (can be changed to 50Hz).
7. Calibration: Zero and span calibration available for voltage/current ranges.
8. Verification: Use Modbus registers or ASCII commands to verify input readings.

Default Settings (EX9018-M):
- Protocol: Modbus RTU
- Module Address: 01
- Baud Rate: 9600 bps
- Filter: 60Hz rejection
- Checksum: Disabled

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7. Performance & Capabilities

- Measurement Speed: 10 samples per second across all channels.
- Resolution: 16-bit ADC ensures fine granularity and low noise.
- Accuracy: ±0.1% of full scale, suitable for precision temperature control.
- Noise Rejection: 150 dB CMR and 100 dB NMR at 50/60 Hz minimize interference.
- Temperature Stability: Low drift ensures consistent readings over wide temperature ranges.
- Cold Junction Compensation: Provides accurate thermocouple readings without external reference junctions.
- Dual Watchdog System:
- Module Watchdog: Hardware circuit ensures continuous operation under noise or fault conditions.
- Host Watchdog: Software timer monitors communication; if timeout occurs, outputs revert to safe state.
- Reliability: EEPROM stores configuration data; module resumes operation with last known settings after power cycle.
- Limitations:
- No individual channel configuration (available only on EX9019 variants).
- Break-line detection not supported on base EX9018-M (available on BL models).
- Warm-up period of 30 minutes recommended for optimal accuracy.

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8. Standards & Compliance

- Communication Standard: RS-485, Modbus RTU protocol compliant.
- Electrical Isolation: Galvanic isolation between input and communication circuits.
- EMC Compliance: Designed for industrial electromagnetic compatibility (EN 61000-6-2 / EN 61000-6-4 typical).
- Safety: Low-voltage DC operation (10–30V).
- Industry Standards:
- Modbus RTU (EIA/TIA-485 standard)
- Thermocouple measurement per IEC 584-1/ANSI MC96.1
- Quality Assurance: Manufactured under ISO 9001 quality management system.

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9. Additional Information

Warranty:
Typically covered by a 2-year limited manufacturer warranty against defects in materials and workmanship.

Technical Support:
- Configuration and troubleshooting assistance via manufacturer’s support portal.
- Firmware updates and utilities available from ICP DAS / EX Series website.
- Modbus register maps and command sets provided for integration.

Maintenance:
- Periodic calibration recommended for high-accuracy applications.
- Keep terminals clean and ensure proper grounding to avoid noise interference.
- Verify thermocouple connections and replace damaged sensors as needed.

Firmware & Updates:
- Firmware version readable via command `$AAF` (e.g., returns version M6.92).
- Module name and address configurable via ASCII or Modbus commands.
- Supports firmware-level Modbus mapping for analog inputs, cold junction temperature, and configuration registers.

Modbus Register Mapping (EX9018-M):
- Analog Input Values: 30001–30008 (input registers)
- Cold Junction Temperature: 30129
- Input Type Codes: 30201–30208
- Channel Enable: 30221
- Data Format: 30269 (0 = engineering units, 1 = 2’s complement)
- Channel Offset Values: 30291–30298

Engineering Data Conversion Examples:
- Type K thermocouple: -270°C to +1372°C → Modbus data / 10 = °C
- ±2.5V range: Modbus data / 10000 = V
- ±20mA range: Modbus data / 1000 = mA

Operational Notes:
- Warm-up for 30 minutes before measurement for best accuracy.
- Use shielded cables for thermocouple and analog inputs to minimize noise.
- Ensure proper RS-485 termination and biasing for stable communication.
- Avoid calibrating unless fully understood; incorrect calibration may affect accuracy.

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Summary

The EX9018-M is a versatile, high-precision analog input module optimized for thermocouple and low-level voltage measurement in industrial automation systems. With 8 differential inputs, 16-bit resolution, and Modbus RTU communication, it provides reliable and accurate data acquisition for temperature and process monitoring. Its robust design, galvanic isolation, and dual watchdog system ensure dependable operation in harsh environments. The module’s flexible configuration, wide input range, and compatibility with standard Modbus systems make it an ideal choice for engineers and integrators seeking a compact, high-performance temperature measurement solution.