Nessie Services was asked to develop a refrigeration control
with interlocks to a GEA dual screw compressor.
The glycol is controlled by temperature and pressure (PID loops).
Of course the HMI is operator friendly as usual
(handling possible without reading manual).
3 redundant pump sets for Cooling Tower,
primary and secondary Glycol (each 7.5KW)
with Schneider Softstarters and Siemens Sinamics VSD's (via Profibus).
An ammonia detector shuts down the plant in case of a leak and opens
an automatic roof top ventilator.
Nessie Services provided:
electrical drawings
control panel layout
PLC programming
HMI development and programming
functional description
commissioning
Components:
Siemens Simatic S7 315 with digital and analog IO's
Siemens HMI: MP277 10" Touch Panel