PLC/HMI Programming for Cascade Chamber

Technical Work Specification & Scope of Work Project Title: Automation, PLC Logic Programming, and HMI Screen Development for -70°C Cascade Cooling Environmental Test Chamber 1. System Overview & Hardware Architecture The supplier/programmer is required to develop, test, and commission the complete automation logic and HMI interface for a specialized -70°C multi-stage cascade refrigeration environmental test chamber. PLC Hardware: Delta DVP-16SS2 main CPU, DVP08SN (SN08) digital output expansion module, DVP04AD-S analog input module, and DVP04PT-S RTD temperature input module. HMI Hardware: Flexem 7000 Series HMI (FE7000 / FE7300) communicating via RS-485 Modbus RTU (COM1 port, 9600 baud, 7 data bits, Even parity, 1 stop bit). 2. Scope of PLC Programming (WPLSoft) Analog Data Acquisition: Configure FROM/TO instructions to read PT100 Class A temperature sensors (Chamber live temperature D100, specimen safety temperature D102, and refrigeration coil temperature D104) along with analog pressure transmitters and humidity sensors (D110 to D115). Compressor Cascade Sequencing & Interlocks: Implement master safety interlocks (M0 derived from emergency stops, door switches X2, and water/airflow flow switches X3). Program a 2-minute equalization timer (T0) and strict sequence interlocks ensuring the Higher Side compressor starts first, followed by the Lower Side compressor based on discharge/suction pressure feedback and safety trips (M101, M103). Control multiple solenoid bypass valves (Y13 to Y17) and the main liquid line solenoid valve (Y20). PID Heating & PWM Control: Implement standard PID instruction loop using chamber temperature (D100), target setpoint (D20), and tuning registers (D200–D203), coupled with GPWM output instruction to drive the booster solid-state relay heater (Y7). 3. Scope of HMI Programming (Flexem FStudio) Dashboard & Navigation: Design an intuitive multi-screen HMI application including a Home Dashboard, P&ID Refrigeration Circuit screen, Timer/Parameter Settings page, and Alarm/Trend screen. Tag Mapping & Controls: Configure numeric displays for live temperatures and pressure transmitters (D100–D115), numeric entry fields for temperature setpoint (D20) and equalization time delay (D220), maintained bit switches for system start/stop (M10), and multi-state indicator lamps for compressors (Y3, Y4), blowers (Y6), and solenoid valves. 4. Deliverables & Acceptance Criteria Fully compiled and error-free WPLSoft ladder logic file (.wpl / .gxw). Compiled Flexem FStudio project file (.fpg) ready for USB/Ethernet download. On-site or remote communication verification between Delta DVP-16SS2 PLC and Flexem HMI.