12. Programming using the programming menus
12.3.5 Limit values
Two limit values (MAXIMUM and MINIMUM) can be programmed per measur-
ing channel. Exceeding one of these limit values is treated as a fault (in the
same way as exceeding a measuring range limit or as sensor breakage). In the
display in front of the measured value an arrow appears
or
, an alarm sig-
nal sounds (to switch this off see 12.5.8), and the alarm relay connected via a
relay cable is triggered (see 12.6.2). Limit values can also have relays assigned
to them (see 12.4.3). This alarm status remains effective until the measured
value returns to within the prescribed limit value by the amount set as hystere-
sis. Hysteresis is set by default to 10 digits but this can be adjusted to any num -
ber between 0 and 99 (see 12.5.7). The event of a limit value being exceeded
can also be used to start or stop a measuring operation (see 12.4.3).
Function
Enter limit value, maximum (see 10.5):
7 Limit max: 123.4°C
Limit value, minimum
7 Limit min : -----°C
To switch off limit values :
<OFF>
To switch on limit values :
<ON>
12.3.6 Scaling, Decimal point setting
To display the electrical signal of a sensor as a measured value in its physical
size it is nearly always necessary to perform a zero-point shift and multiplication
by a factor. To perform these steps the functions BASE and FACTOR are pro-
vided. For a detailed description of scaling, with an example, please refer to the
Manual, Section 6.3.11.
Displayed value
= (corrected measured value - BASE) x FACTOR
The FACTOR can be programmed within the range -2.0000 to +2.0000. For
factors above 2.0 or below 0.2 an appropriate decimal point setting should be
used by entering EXPONENT. Using EXPONENT the decimal point can be
shifted as far to the left (-) or to the right (+) as the display and printer permit.
An exponential view of measured values is not possible.
To calculate the scaling values automatically :
5 Base value: ------
5 Factor: ------
5 Exponent: 0
from the actual values and setpoints the
WIZ-
ARD menus
include the menu
Scaling
.
Once the scaling values have been pro-
grammed and the actual measured value thus
modified the correction arrow appears indicat-
ing the measured value status (see 10.2).
64 ALMEMO
®
5690-2M
* SCALING *
±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±
Connector: 0 Channel: 00
Actual value 1:
4.000 mA
Actual value 2:
20.000 mA
Decimal places:
1
2 Dimension:
°C
Setpoint 1:
-100.0 °C
Setpoint 2:
400.0
°C
5 Base:
720.0 °C
5 Factor:
0.3125
5 Exponent:
2
4 Slope correct: ------
00: 27.0 °C
CLR F OK ESC
