Peristaltic Chemical Feed Pumps These controllers are equipped with two peristaltic dosing pumps with replaceable chemical resistant tubing that are proportionally controlled with adjustable ºow rates. One of the pumps is used to dose acid or base while the other is used to dose chlorine. The e¨ectiveness of the available chlorine, as determined by ORP, is inversely related to the water’s pH value. Multicolored LED Indicators The controllers o¨er multiple LED indicators for status, servicing, and pump operation. The STATUS LED changes color based on operational state; a green LED means the water is within the desired parameter ranges, a yellow LED means that the controller needs attention, and a red LED identies a problem in the system such as high and low pH, ORP and/or temperature readings. The SERVICE LED indicates attention is required by a service technician. Automatic Proportional Pump Control BL120, BL121, BL122, and BL123 feature proportionally controlled dosing pumps. The user can set the proportional band based on the sensitivity of the process. This setting determines the amount of time that the pumps are dosing as a percentage of the deviation from the set point. For example, a large body of water will use a small proportional band; having a small band (e.g., 0.1 pH) will ensure the pumps are dosing more often when the reading is close to the set point. For smaller bodies of water such as hot tubs or spas, it is more useful to set a larger proportional band (e.g.,1.0 pH); when the reading is close to the set point, the amount of time that the dosing pump is on is minimal to avoid large swings of pH or ORP. This valuable feature allows for very ne control in maintaining the desired set point. Adjustable Flow Rate The dosing pump ºow rate is adjustable from 0.5 to 3.5L/h. Larger bodies of water require more chemical to be dosed than small bodies since it takes more chemical to see a change in the reading. The adjustable ºow rate, like the proportional band, allows for better control in maintaining a desired set point. ORP (Chlorine) Dosing Consent Both pH and ORP meters are commonly used with swimming pools. With chlorine disinfection there is an inverse relationship between pH and ORP. As the pH level increases, the ORP level decreases. These controllers utilize a dosing consent feature that will not dose chlorine until the pH value is rst corrected since it is possible to have a low ORP value even though there is su³cient chlorine. The dosing consent feature prevents waste of chemicals and avoids having a higher chlorine concentration level than desired. Acid and Chlorine Tank Level Inputs The controllers allow for a connection to an optional level controller. This input is used to disable the dosing pumps when there is no chemical left in the reservoir tank. Programmable Alarm System These controllers allow users to enable or disable the low and high level of alarms for all parameters: pH, ORP, and temperature. When an alarm is activated, all dosing will stop. The alarm system also o¨ers overdosing protection in that if the value is not corrected within a specied time interval then the meter will go into alarm status. Automatic Logging Congurable logging intervals can be set at 30 seconds; 1 minute; 2 minutes; 5 minutes; 10 minutes; 15 minutes; 30 minutes; 60 minutes, with a new log starting new each day, when the instrument is calibrated or settings have changed. Logged data includes pH, ORP, and temperature values, last calibration data, setup conguration, and any event data. The meter can store 100 logs. Additional Features 15 Process Instrumentation 15.26 | www.hannainst.com controllers
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