Chromalox TEMPERATURE CONTROLLER 1604-7 - Manual (Page 28)

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ERROR MESSAGES
OVERRANGE, UNDERRANGE AND
SENSOR LEADS BREAK INDICATIONS
The device is capable to detect a fault on the
process variable (OVERRANGE or
UNDERRANGE or SENSOR LEADS BREAK).
When the process variable exceeds the span
limits established by configuration parameter P 1
an OVERRANGE condition will be shown on
display as show in the following figure:
An UNDERRANGE condition will be shown on
display as show in the following figure:
When P37 is equal to 0, the following conditions
may occur:
- The instrument is set for one output only and if
an OVERRANGE is detected, the output turns
OFF (if reverse action) or ON (if direct action).
- The instrument is set for heating/cooling action
and an OVERRANGE is detected, "rEV" output
turns OFF and "dir" output turns ON.
- The instrument is set for one output only and if
an UNDERRANGE is detected, the output turns
ON (if reverse action) or OFF (if direct action).
- The instrument is set for heating/cooling action
and an UNDERRANGE is detected, "rEV"
output turns ON and "dir" output turns OFF.
When P37 is different from zero and an out of
range condition is detected, the instrument
operates in accordance with P37 and P38
parameters.
NOTE: in every cases, the P18 and P20
parameters will conditioned the real outputs of the
instrument.
The sensor leads break can be signalled as:
- for TC/mV input :
OVERRANGE or
UNDERRANGE selected by
a solder jumper
- for RTD input : OVERRANGE
- for mA/V input : UNDERRANGE
NOTE : For mA/V input the leads break can be
detected only when the range selected has a zero
elevation (4/20 mA or 1/5 V or 2/10 V)
For RTD input a special test is provided to signal
OVERRANGE when input resistance is less than
15 ohm (Short circuit sensor detection).
ERROR MESSAGES
The instrument performs same self-diagnostic
algorithm.
When an error is detected, the instrument shows
on the lower display the “Err” indication while the
upper display shows the code of the detected
error.
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