Function Blocks
3/99 Function Block Reference Guide 59
2.15 CARB Function Block,
continued
Example
Figure 2-13 shows Function Block Diagrams using an CARB function block
Supports Zirconia Probes from:
Super Systems Inc., Marithon Monitors
Furnace Control Corp., Advanced Atmosphere
Uses a single block for %C calculation and PID control Supports
CO Compensation from an Analyzer input or a fixed value (use
20% as default for Methane)
Calculates Dewpoint applied to separate output
Provides a Furnace Factor Bias adjustment (to
adjust %C to match lab samples)
Provides Anti-sooting setpoint limiting
Probe burn-off using standard logic functions
%CO, 0-100%
DegC or F
0-2000 mV Range
Carbon Potential Probe Burn-off
Application:
To clean a carbon probe periodically
by blowing air across it for a specific
time.
In this configuration, a periodic timer
generates a pulse a designated time
interval which suspends automatic
control and energizes a relay output
to cause air flow for a probe burn off
cycle. Timers determine the probe
burn-off period and allow time for
the probe recovery before returning
the loop to automatic control.
PTMR Output
MDSW Output
Burnoff Time
Time Delay to AUTO
Manual
Auto Auto
Off delay #1
Off delay #2
Configuration Notes:
Select probe Mfg.. type
O2 probe input: 0 to 2 V.
(0 to 2000 range)
Select T/C type J or K etc..
Timing Diagram
Figure 2-13 CARB Function Block Examples