Instruction Manual

mxCONTROL Type 8620
Page 109
14.4 Corrosion Display (CORROSION-DISPLAY)
The corrosion display indicates the corrosion rate measured by the corrosion transmitter. Although
this function is not used directly for control purposes, it provides useful system status information.
These modules
are explained
below.
Figure 47: CORROSION_DISPLAY
Acid Stop Limit (ASL)
If the corrosion rate exceeds the predefined value, the Acid Stop Limit ASL, the ASL alarm for this
Function is activated and the general alarm output is triggered. The ASL alarm is disabled again if the
process value is less than the ASL minus the ASL-hysteresis.
The ASL-Alarm can be used in combination with the controller modules PH_ACID_CAUS and
PH_ACID_OR_CAUS as additional failsafe for preventing overdosing of acids or bases. Hereby
both acid and caustic outputs (if existing) of the connected pH controller modules are set to "0" (shut
off), as long as the ASL-Alarm is active. If the system switch override for this module is configured and
becomes active (stand-by), the ASL alarm is disabled again.
Refer also to the description of the pH Controller Modules in chapter
14.5.1 and 14.5.2.
Processdata and Data Logging
Display-Presentation Displayed data
Abbre-
viation
(menu)
Full
Screen
Trend
chart
Line
Data-
Log.
Notes
Process value PV
x x x
Acid Stop Limit
ASL
x x
Data Logging: Only
ASL alarm
Parameter (CodeLevel: Operator)
Parameter
Abbrevia-
tion
(menu)
Value range
Default values
(after successful download of
Cfg-File)
Acid Stop Limit ASL Scal- …Scal+ of the assigned input Scal- + ((Scal+ - Scal-) /2)
ASL hysteresis Hyst 0.1 ... 10.0 % of input range 1.0 %
Configuration (Code Level: Specialist)
Configuration
Access
via
Cfg.-
menu
Access
via XML-
Cfg.-File
Abbreviation
(menu)
Value range
Default values
(after factory reset or
at start of Cfg-File-
Download)
Module active/not active rw rw Module On/Off Off
System switch override rw rw SSOR Yes / No No