Micromod MOD: Modcell 2050R Users Guide - Manual (Page 195)

IB-23C650
RATIO BIAS CONTROL
Instrument Set-up
To implement an A/M Ratio Bias Station, enter into the BASE CFG **MENU**,
Table 1, and enable A/M Ratio Bias Station at the RAT BIAS ENABLE
prompt. If the ratio or bias value is to come from an external source, input two
must also be enabled. Configure the station using the RAT BIAS **MENU**,
Table 7. The station type can be designated as ratio only, bias only or both
ratio and bias. Initial (startup) values for local ratio and bias can be entered in
the TUNE **MENU**,Table 12, at the A/M R-B RATIO or A/M R-B BIAS prompt.
The bias value is displayed in engineering units and is converted to percent
for calculation of the output. Setting the process input engineering high and
low values to 100 and 0 respectively allows the user to work in percent.
A/M Switching
Auto/manual switching in the A/M ratio bias station and dependent variable
controller have very similar functions. Switching from automatic to manual in
either instrument breaks the connection between the independent and
dependent variables. When the A/M ratio bias station is switched to manual,
the manual control adjustment in the station provides the set-point for the
dependent variable. When the controller is switched to manual, the dependent
variable is under direct manual control from the front panel of the controller.
Note: The remote/local switch does not function in an A/M Ratio Bias
Station. The source of the ratio or bias is configured as local or
remote in the RAT BIAS **MENU**.
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