Mercoid Series 3100 Explosion-Proof Differential Pressure Transmitter

Chapter 1: Introduction

This manual provides information on installing, operating, and maintaining the Mercoid® Model 3100 Smart Pressure Transmitter. The document is organized into chapters covering handling, functions, installation, operation, and maintenance.

The Series 3100 is a microprocessor-based pressure transmitter featuring a capacitance sensor optimized for draft measurement. It offers explosion-proof design, high precision, reliability, and digital communication capabilities via HART® protocol. It requires a 250-550 Ohm resistance for HART® communication.

Chapter 2: Handling Cautions

This chapter outlines essential cautions for handling, storage, and installation. Key points include:

• Unpacking & Checks: Verify the transmitter nameplate matches the purchase order.
• Storage: Store in a dry, non-vibration, non-impact area with controlled temperature (approx. 77°F/25°C) and humidity (65% RH). Specific ambient temperature and humidity ratings are provided for different configurations.
• Installation Locations: Select sites with stable ambient temperatures, non-corrosive atmospheres, minimal shock/vibration, and easy maintenance access. Ensure the area classification does not exceed the explosion-proof rating.
• Pressure Connections: Exercise caution when connecting to pressurized systems. Never loosen or tighten fittings under pressure.
• Cable Conduit: Use waterproof sealant for cable conduit connections.
• Explosion-Proof Requirements: Adhere to specific installation requirements for hazardous locations and explosion-proof ratings (FM, ATEX certified).
• Testing: Insulation resistance and dielectric strength tests are typically performed at the factory but can be conducted if necessary, following specific voltage and procedure guidelines.

Chapter 3: Transmitter Functions

This chapter details the transmitter's functions, configuration, and safety messages.

• Safety Messages: Pay close attention to warnings regarding explosion hazards (e.g., do not open covers in explosive atmospheres) and electrical shock (qualified personnel only).
• Fail Mode Alarm: The transmitter performs self-diagnostics and drives the output outside normal values (low or high) upon detecting a failure, configurable via jumper settings.
• Security Settings: Includes a security jumper to protect configuration parameters and the option to physically remove magnetic buttons to prevent local zero/span adjustments.
• Configuration: Procedures are described for setting zero, span, zero trim, adjustments, units, range, dampening, and LCD display settings using the transmitter's buttons.
• Commissioning: The transmitter can be commissioned on a bench using a Hand-Held Terminal (HHT) or PC configurator before or after installation, requiring specific power supply and loop resistance.

Chapter 4: Installation

This chapter provides comprehensive installation guidelines.

• General Considerations: Mount the transmitter near the process to minimize piping, ensuring easy access for personnel and maintenance. Avoid excessive vibration.
• Electrical Considerations: The transmitter requires a 11.9-45 VDC power supply. HART® communication requires a 250-550 Ohm loop resistance.
• Wiring: Install signal cables away from electrical noise sources. Ensure all screwed connections are sealed. Use appropriate wiring materials rated for the environment. Grounding must comply with local electrical codes and explosion-proof requirements.
• Diagrams: Figures illustrate typical mounting, wiring configurations (general-use and explosion-proof), and terminal connections.
• Mechanical Considerations: Outlines dimensions and mounting options, including the use of an A-630 angle bracket for pipe mounting.
• Environmental Considerations: Details acceptable ambient temperature ranges (-20 to 60°C), protection against moisture and toxic materials, and installation within hazardous locations according to explosion-proof ratings.

Chapter 5: On-line Operation

This section covers the configuration and operation of the transmitter.

• Configuration: The transmitter can be configured online using an HHT or PC configurator, or offline. Configuration involves setting process variables, sensor range, output units (including a wide range of volumetric, mass, and pressure units), and 4-20mA output scaling.
• Detailed Setup: Includes setting the fail mode and dampening time to control response to process changes.
• Information Variables: Users can set 'Tag' and 'Message' for transmitter identification.
• Diagnostics & Service: A 'Loop Test' function is available to verify transmitter output, loop integrity, and connected devices.
• Calibration: Procedures for Sensor Trim (zero trim, full trim) and D/A Trim are detailed to optimize performance and correct minor offsets.

Chapter 6: Maintenance

This chapter addresses diagnostics and maintenance procedures.

• Safety Messages: Reinforces safety precautions for operation and maintenance.
• Hardware Diagnostics: A troubleshooting table is provided to help diagnose common issues such as communication failures, high/erratic/low output, and potential causes like loop wiring, power supply, or electronics module faults.
• Hardware Maintenance: The transmitter has minimal moving parts and requires little maintenance. If a failure occurs, it should be returned to Dwyer Instruments, Inc. for service. Test terminals are available for diagnostics.
• Housing: The transmitter features a dual-compartment housing for electronics and wiring terminals. Procedures for disassembling the housing and locating jumper switches are described.

Appendix I: 3100 Smart Pressure Transmitter - LCD Display Code

This appendix lists various LCD display codes and their corresponding descriptions, aiding in the interpretation of transmitter status and error messages.