Programming with Design Pad G4
- Gary Cane
Fairmount Automation's controller products are programmed with a graphical programming software package called Design Pad G4. All "programming" is done graphically---by "drawing" connections between functional operator blocks (see Figure 2.1 for a sample "program").
Design Pad G4 supports over 150 operators, including
•Controllers (e.g., PID controller, lead-lag controller)
•Data Conversion (e.g., binary to decimal)
•Data Logging (e.g., strip-chart recorder, snap-shot recorder)
•Diagnostic (e.g., breakpoint, module position)
•Signal Generators (e.g., ramp profile, pulse-width modulation)
•Logic (e.g., NAND gate, XOR gate, RS flip flop)
•Math (e.g., addition, multiplication, exponential, trigonometric sine)
•Signal Comparators (e.g., high/low alarm, equality, less or equal)
•Signal Conditioning (e.g., characterizer, rate limiter, track & hold)
•Signal Switching (e.g., A/B Switch, demultiplexer, min/max selector)
•Signal Reference (e.g., variable, constant)
•Sub-Schemas (e.g., custom function-block, state diagram)
•Hardware I/O resources (e.g., analog input, relay output)
•Hardware U/I resources (e.g., numeric display, pushbutton)
•Hardware Timing Resources (e.g., alarm clock, calendar, stop watch, timer)
•Hardware Built-in Test (e.g., self-diagnostic, module hardware info)
•Networking Operators (e.g., Modbus register coil, LonTalk network variable)
A detailed description of all the operators available in Design Pad G4 is provided in the companion instruction bulletin." Design Pad G4 Operator Reference", publication PDG-TR-2011/13.
The collection of operators and their associated interconnections is called a control schema. The schema diagram represents the actual program that will be executed on the target controller hardware. The specific controller configuration identifying the available hardware elements is defined in a separate document called the hardware interface file. The sections that follow describe how to create a hardware configuration and associated control schema(s), as well as how to download the control algorithms into the actual controller hardware.
