Walchem WDIS Series Instruction Manual

Walchem WDIS Series Instruction Manual Manual pdf 23 page image

19is insufficient may be installed in the line, so that if flow past the sensor stops, the controller will notpump in chemicals based on a stagnant sample. Similarly, a level switch may be attached to preventcontrol of an empty batch tank.Control DirPress ENTER to change the direction of control, then use the Up and Down arrows to toggle betweenHigh Set Point and Low Set Point, and press ENTER to make your choice. A low set point will turnon the relay when the process value goes below the set point value (to add an oxidizer, or as a lowalarm). A high set point will turn on the relay when the process value goes over the set point value (toadd a reducing agent, or as a high alarm).HOAUse the Left and Right arrows to move between Hand, Off and Auto. In Hand (Manual) mode, theoutput will be turned on immediately for a maximum of 10 minutes. In the Off mode, the output willbe turned off indefinitely. In the Auto mode, the output turns on and off in response to changes in theprocess value relative to the set point. The letter inside the block on the status screen indicates whichmode the output is in.DEADBANDLOW SETPOINTppmTIMEPump OffPump OnPump OffLOW SETPOINTppmTIMEZERO DEADBAND: NOT RECOMMENDEDPump On & Off rapidly, damaging relay