I've heard of process controllers-- such as this one (that is available with one of the control outputs as a 4-20ma analog)--
http://www.automationdirect.com/adc/Shopping/Catalog/Process_Controls/Temperature_-z-_Process_Controllers/1-z-16_DIN_Size_(SL4848_-z-_PM_-z-_TC_-z-_PC_Series)/SL4848-CR
being used to drive a variable speed motor control such as the Nimbus. I understand the aspects relating to how a 4-20ma signal is ued to vary the output of the speed control-- but what I have not yet been able to find (despite reading the manual at
http://www.automationdirect.com/static/manuals/solocontrolm/solocontrolm.pdf )
is how you set the control to have upper and lower temperature 'bounds' for the 4-20ma variable speed. Can anyone please give me or point me towards a tutorial (need not be for this specific process controller, which I am just using as an example) to help me get a better understanding of putting that function to use? My current possible application is to vary a pump speed for boiler return protection when the boiler is faced with the tremendous thermal mass of water storage that has begun at low (55 F) temperature.
Thanks
http://www.automationdirect.com/adc/Shopping/Catalog/Process_Controls/Temperature_-z-_Process_Controllers/1-z-16_DIN_Size_(SL4848_-z-_PM_-z-_TC_-z-_PC_Series)/SL4848-CR
being used to drive a variable speed motor control such as the Nimbus. I understand the aspects relating to how a 4-20ma signal is ued to vary the output of the speed control-- but what I have not yet been able to find (despite reading the manual at
http://www.automationdirect.com/static/manuals/solocontrolm/solocontrolm.pdf )
is how you set the control to have upper and lower temperature 'bounds' for the 4-20ma variable speed. Can anyone please give me or point me towards a tutorial (need not be for this specific process controller, which I am just using as an example) to help me get a better understanding of putting that function to use? My current possible application is to vary a pump speed for boiler return protection when the boiler is faced with the tremendous thermal mass of water storage that has begun at low (55 F) temperature.
Thanks