Mobile Automation designed, built and commissioned the control and data systems for a major appliance manufacturer's new MEPS (Minimum Energy Performance Standards) test laboratory — two environmental rooms where appliance energy performance is measured against the standard. A test laboratory is only as good as its numbers.
Holding the room conditions, and proving them
Each room measures its own conditions and shows what every reading is worth.
- Calibrated Vaisala transmitters read over Modbus by a Siemens controller, with RTD inputs for direct temperature measurement
- Dual-circuit relative humidity measurement commissioned and verified in both rooms
- Calibration coefficients applied in the PLC, with SCADA multiplexing between calibrated and uncalibrated readings
- Raw and corrected values shown side by side when a transmitter returns from calibration
- Dew point calculated from the same data, and humidity held by a steam humidifier under PID control
- Modbus client written by our engineers with its own state machine, so a transmitter that drops off is detected rather than reported as a last-known value
Safety proven room by room at commissioning
The safety system was function-tested rather than assumed.
- Gas detection supply moved onto the safety card so it drops with the rest of the safety system
- Every E-stop function-tested
- Laboratory lighting brought under safety control
Getting the data out
Room conditions are only useful next to the energy figures they produced.
- Power meter on the device under test integrated, so consumption is logged against the room conditions that produced it
- Circulation pump brought onto the network through its communications card for on/off control, remote setpoint and pressure feedback
- Customer's independent data logger integrated over Modbus, keeping their measurement chain separate from ours
- Single-login administrator interface with trend pages covering all of it
The results
- Two environmental rooms commissioned and holding conditions to the standard
- Communications recover from a dropout without an operator intervening
- Handed over with wire numbering, as-built drawings and a written commissioning report