WIKA CF2S - Manual (Page 33)

Operating Instructions Temperature Indicating Controller CF2S
V1.2 • 08/2004 - 33 -
9. Other functions
(1) Burnout alarm
(Upscale)
When the thermocouple or RTD is burnt out or the input value exceeds [Rated scale
maximum value +1% of rated scale span], the control output is turned OFF (main output
low limit value for the current output type) and the PV display blinks [
].
With the input RTD Pt100 (°F), if the input value is greater than 999.9, the PV display
blinks [
], however, the control is performed to [rated scale maximum value +1% of
rated scale span].
(Downscale)
When the input value falls to [Rated scale minimum value –1% of rated scale span] or less,
the control output is turned OFF (main output low limit value for the current output type)
and the PV display blinks [
].
For the Thermocouple T or RTD input, if the input falls to less than –199.9, the PV display
blinks [
], however, the control is performed to [rated scale minimum value –1% of
rated scale span].
(2) Self-diagnostic function
The CPU is monitored by a watchdog timer, and when any abnormal status is
found on the CPU, the controller is switched to warm-up status.
(3) Automatic cold junction temperature compensation (Thermocouple input type)
This detects the temperature at the connecting terminal between thermocouple
and the instrument, and always keeps it at the same status as when the
reference junction is located at 0°C [32°F].
(4) Warm-up indication
For approximately 2 seconds after the power supply to the instrument is turned on,
the type of input and the temperature unit are indicated on the PV display, and the
maximum input rated value on the SV display.
(5) Setting value ramp function
When the main setting value is adjusted, it approaches the new setting value by the set rate
of change.
When the power is turned on, the control starts from the PV (process variable)
and approaches the main setting value by the rate of change.