Digital guide
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MTL 8220-DI-IS
Product Name: PAC8000 16-Channel Intrinsically Safe Digital Input Module for Switches and NAMUR Proximity Detectors
Product Introduction: This module receives discrete contact or proximity states from hazardous-area switches and transmits filtered on/off status to the PAC8000 control system. It removes the need for separate zener or galvanic barriers in many IS installations.
Detailed content
Technical Specifications: 16 single-ended intrinsically safe digital inputs; sensor supply 7–9 V DC; on-state current greater than 2.1 mA; off-state current less than 1.2 mA; selectable input filter 50–512 ms depending on configuration; system current approximately 350 mA; open- and short-circuit field-wire fault detection; PAC8000 Railbus communication through Bus Interface Module or controller.
Functional Features: NAMUR proximity and dry-contact compatibility; line-fault detection for open and short conditions; configurable debounce or filtering; per-channel activation; high-density 16-point design; mechanical keying to prevent wrong module insertion.
Performance Parameters: NAMUR thresholds aligned with DIN 19234/EN 60947-5-6; short-circuit fault typically detected above approximately 90 kΩ depending on configuration; pulse counting capable on selected variants with maximum frequency and minimum pulse width defined by firmware; operating temperature -40 to +70 °C; IP20 module class with IS field terminals.
Material And Structure: Conformal-coated PCB; IS field terminal block; PAC8000 carrier or DIN-rail mount; galvanic isolation between field loop, Railbus and logic; blue IS connector identification where required by site standard.
Working Principle: The module supplies a limited IS voltage to the field switch or NAMUR sensor. Internal comparators evaluate current or resistance state, filtering classifies on/off, and the Railbus interface reports status, alarms and wiring-fault diagnostics to the controller.
Installation Requirements: Install in PAC8000 IS carrier with approved IS digital field terminal; use IS-rated cable for Zone 1/Division 1 loops; separate IS and non-IS wiring trays; verify mechanical keying; configure filter time to match switch bounce and proximity response.
Application Scenarios: Emergency-stop and safety pushbuttons in hazardous areas, NAMUR proximity position feedback, valve-limit switches, pump running status, tank-farm level switches and chemical-plant motor feedback.
Usage Precautions: Do not connect standard 24 V discrete devices to IS inputs without recalculating loop energy. Verify NAMUR versus dry-contact configuration before commissioning. Never share terminals between IS and non-IS circuits. Test open/short detection after installation using the configured threshold values.
