Hach-Lange RTC112 SD-Module - Manual (Page 12)

12
General information
Figure 2 Design of the analog and digital input and output modules
Note: The number of green LEDs indicates the number of channels.
2.5 Theory of operation
2.5.1 Theory of operation of the RTC Module
The RTC112 SD-Module outputs analog (0/4–20 mA) and digital (0/24 V) signals for the
polymer dosing rate or the feed flow rate of mechanical sludge dewatering devices. Digital
fieldbus signals from sc1000 communication cards can also be used.
2.5.2 Input signals
The most important input signals are:
• Sludge influent TSS concentration (concentration of solids)
• Feed flow rate of the dewatering system
• Thickened sludge TSS concentration (optional)
• Status of the thickened sludge pump (on/off)
2.5.3 Parameters for configuration
The most important parameters for configuration are:
• The required specific polymer dosing [g polymer/kg TSS]
• The target TSS concentration in dewatered sludge or
• The target TSS concentration in centrate
1 Input- or Output- Module or Bus Termination Module
analog or digital 2 LED area with installed LEDs or free LED installation
spaces
2
1