Super Systems 20PQ - Manual (Page 140)

136
ERROR MESSAGES
OVERRANGE, UNDERRANGE AND SENSOR LEADS
BREAK DETECTION
ON THE MAIN INPUT
The device is capable to detect a fault condition on the main
input (OVERRANGE or UNDERRANGE or SENSOR LEADS
BREAK).
When the process variable exceeds the full scale value
programmed by "ñ.In.t" [C.d02], an OVERRANGE condition will
be shown on the upper display as show in the following figure:
When the process variable is lower than the initial scale value
programmed by "ñ.In.t" [C.d02], an UNDERRANGE condition
will be shown on the upper display as show in the following
figure:
In presence of an main input out-of-range condition, the control
outputs operate as follows:
a) When “SF.Cn” [C.G09] is set to “Std.”:
a.1) An OVERRANGE is detected and
- the device is set for one control output only, the output
will be forced to 0 % (if reverse action is programmed)
or to 100% (if direct action is programmed).
- the device has two control outputs, the “Main” output is
forced to 0 % and “Secondary” output is forced to 100%.
a.2) An UNDERRANGE is detected and
- the device is set for one output only, the output is
forced to 100 % (if reverse action is programmed) or to
0 % (if direct action is programmed).
- the device has two control outputs, the “Main” output is
forced to 100 % and “Secondary” output is forced to 0
%
b) With “SF.Cn” [C.G09] set to “Ov.Un”, when an overrange or
an underrange condition is detected, the power output is
forced to the safety value “SF.UL” [C.G10].
c) When “SF.Cn” [C.G09] is set to “OvEr”
c.1) if an overrange condition is detected, the power output is
forced to the safety value “SF.UL” [C.G10]
c.2) if an underrange condition is detected the instrument will
operate as described at point a.2).
XKP-1-C2.p65 10/30/01, 9:37 AM 136