Honeywell 9782 Series manual AutoClean Sequence and Piping, Rinse sequence

Conductivity/Resistivity Analyzer/Controller

7.2 AutoClean Sequence and Piping

Rinse sequence

The AutoClean operation occurs at the configured intervals. (It can also be initiated by the operator; see Sub-Section 5.8 for details.) The sequence is described below.

1All alarm action is held at existing levels. The outputs are also held throughout the AutoClean operation.

Pressing the DISPLAY key will call up a special display that shows how much time remains until the start of the next scheduled AutoClean sequence. While the cleaning operation is taking place, “AUTO CLEAN” is displayed on the alarm stripe on the Time Remaining display. The clock will show 00:00:00.

2Relay 1 activates 3-way solenoid valve S1 (see Figure 7-1) to direct rinsing fluid to the cells for the configured rinse duration (1 to 1999 seconds). If the measured sample is normally returned to the process but quantities of rinsing fluid cannot be tolerated there, use an additional 3-way solenoid valve S4. It is activated simultaneously with S1 to divert the discharge to drain.

3At the end of the configured rinse time Relay 1 de-activates solenoid valve S1 (and S4, if used). After the configured delay period (1 to 1999 seconds) the Analyzer/Controller resumes sampling the process. (During the resume delay the “AUTO CLEAN” message flashes.) Note that even with S4 for diversion, one system volume of washing fluid will pass to the process at this point.

4The “AUTO CLEAN” message is cleared.

Note that the operator can make the operation pause using the “soft key” on the special AutoClean Time Remaining display. If the operator does not remove the pause by pressing the PAUSE soft key again, the Analyzer/Controller will resume normal operation after 20 minutes.

7-2 9782 Series Conductivity/Resistivity Analyzer/Controller - Operator’s Manual 7/99