Honeywell DR4300 Product Manual page 93

4.3.5.3 Setting SW6 Burnout Switch
Overview
What happens to the displayed input value when the input signal to the recorder fails depends on several
factors: the input type, the setting of SW6 switch 2, and the value of the "BRNOUT" parameter in the input
set up group.
SW6 switch 2 OFF for RTD
If the input to the pen channel is from an RTD, SW6 switch 2 must always be set to OFF.
CAUTION
If SW6 switch 2 is ON for an RTD input, the recorder will not be able to process the input correctly,
even when the input sensor is providing a valid input signal.
SW6 switch 2 setting unimportant for Volt, mV, and mA inputs
It does not matter whether SW6 switch 2 is ON or OFF if the pen channel uses a Volt, mV, or mA input
signal. In case of input failure, the displayed input value will show little change, regardless of the setting of
SW6 switch 2 or the value assigned to the "BRNOUT" parameter. (However, the value of "BRNOUT" is
still important to implementing your control strategy because the value of "BRNOUT" affects the output
used in case of input failure. See Subsection 4.3.11 for details.)
SW6 switch 2 setting determines displayed thermocouple input if BRNOUT = NONE
If the value of "BRNOUT" is "NONE" when a thermocouple input fails, then the setting of SW6 switch 2
determines whether the displayed input value will be under range or over range. The recorder can display
1 % over or under range for thermocouples.
• If SW6 switch 2 is ON, the displayed value will be under range.
• If SW6 switch 2 is OFF, the displayed value will be over range.
If the pen is configured to trace the input value ("PENIN" pen set up parameter value is "INP"), then the
pen will also be driven over or under range.
Note that the over range or under range input will have no effect on output. When "BRNOUT" = "NONE",
the recorder uses the configured failsafe value as the output in case of input failure, rather than a calculated
value based on input.
SW6 switch 2 setting for thermocouple inputs should match BRNOUT if BRNOUT = UP OR DOWN
We recommend that, in the case of thermocouple inputs, SW6 switch 2 be set to OFF if "BRNOUT" =
"UP" and ON if "BRNOUT" = "DOWN".
When the input failure first occurs, the displayed input for a thermocouple input will briefly be driven
according to the hardware switch setting. However, as soon as the software recognizes that it has received
an out-of-range input signal, the displayed input will be driven according to the value, "UP" or "DOWN",
configured for "BRNOUT". The displayed value (over range or under range) as configured in "BRNOUT",
will remain on the display until a valid input is restored.
4/00 DR4300 Circular Chart Recorder Product Manual
Configuration, Startup, and Operation
of Recorder with Display
81