Technical Specifications:

• Input Channels: 4 universal inputs (TC, RTD, mV, V, mA)
• Output Type: Relay output (1 SPDT contact)
• Communication: None (00 = no communication option)
• Power Supply: 100–240 V AC (50/60 Hz) or 24 V DC
• Control Output: 1 relay output (ON/OFF control)
• Accuracy: ±0.1% of reading + 1 digit (for DC input)
• Display: 5-digit, 7-segment red LED with 14 mm digit height
• Control Modes: ON/OFF control, PID control (automatic tuning available)
• Response Time: 200 ms (typ.)
• Operating Temperature: 0 to 55 °C (32 to 131 °F)
• Storage Temperature: -20 to 70 °C (-4 to 158 °F)
• Panel Cutout: 96 × 96 mm (1/4 DIN)
• Depth: 108 mm (4.25 in)
• Weight: Approximately 450 g (0.99 lb)

Functional Features:

• Heater Burnout Alarm (HBA): Detects open circuit in heating elements
• Loop Break Alarm (LBA): Detects sensor disconnection
• Remote Setpoint (RSP): Accepts external setpoint signal via analog input
• Manual Reset Function: Allows operator-initiated reset after alarm conditions
• Auto/Manual Switching: Seamless transfer between automatic and manual control
• Alarm Outputs: 2 alarm outputs (SP, LH, LL, DH, DL, deviation)
• Event Sequence Recording: Logs up to 1000 events with timestamps

Performance Parameters:

• Input Impedance (Voltage): 10 MΩ (minimum)
• Input Impedance (Current): 250 Ω (for 4–20 mA input)
• Relay Rating: 3 A at 250 V AC (resistive load), 30 V DC
• Insulation Resistance: 100 MΩ minimum at 500 V DC
• Dielectric Strength: 1500 V AC for 1 minute (input to output to power)
• IP Rating: IP65 (front panel), IP20 (rear)
• EMC Compliance: EN 61326-1, EN 61000-6-2, EN 61000-6-4

Structural Features:

• Compact 1/4 DIN (96 × 96 mm) front panel
• Snap-in mounting design for easy installation
• Screw terminal connections on rear panel
• Dual-row terminal block for input and output wiring
• Transparent front cover with LED display window

Working Principle:
The UT55A receives process signals from up to 4 universal inputs. The internal microprocessor compares the process variable (PV) against the setpoint (SP) using a PID algorithm. The deviation signal drives the relay output to energize or de-energize the controlled device. The HBA and LBA functions continuously monitor input circuit integrity.

Advantage Highlights:

• Universal Input Compatibility: Accepts thermocouple, RTD, millivolt, voltage, and current signals on any channel
• Auto-Tuning PID: Built-in self-tuning function eliminates manual PID parameter adjustment
• Heater Burnout Alarm: Unique HBA function prevents undetected heater failures
• High Accuracy: ±0.1% reading accuracy ensures tight process control
• Compact Design: 1/4 DIN size saves panel space compared to full DIN controllers

Applicable Industries:

• Chemical processing
• Food and beverage
• Pharmaceutical manufacturing
• Water and wastewater treatment
• HVAC systems
• Oil and gas
• Pulp and paper
• Power generation

Installation Requirements:

• Panel cutout: 92 × 92 mm minimum, 96 × 96 mm nominal
• Mounting depth clearance: 108 mm from front of panel
• Ambient temperature: 0 to 55 °C during operation
• Avoid direct sunlight exposure on front panel
• Ensure adequate ventilation behind the panel
• Use shielded cables for analog signal inputs

Usage Precautions:

• Do not exceed maximum input voltage/current ratings on any channel
• Verify input type configuration matches actual sensor type before energizing
• Ensure relay output load does not exceed 3 A at 250 V AC
• Perform periodic calibration to maintain ±0.1% accuracy specification
• Do not operate in environments with corrosive gases without additional enclosure protection