15. Sensor programming
15.12.3 Analog output start / end
The analog output of measured values to the analog output modules or to the
display as a bar chart must in most cases be scaled to a particular sub-range
(see Manual 5). This can be done by simply stipulating the start value and end
value of the range to be displayed. This range will then be mapped to the ana-
log range 2 V, 10 V, 20 mA, or a bar chart display with 100 pixels.
To program the analog output - start
6 Analog Start:
0.0°C
To program the analog output - end
6 Analog End:
100.0°C
These two parameters, 'analog output start' and 'analog output end', are also
saved in the sensor EEPROM and can thus be individually programmed per
channel; i.e. when channels are switched through manually each measurable
variable can be individually scaled. The flag for switching over from 0 - 20 mA
to 4 - 20 mA is programmed via the element flags (s. 15.12.7, 17.3).
15.12.4 Minimum sensor supply voltage
As with all ALMEMO
®
devices the sensor sup-
ply voltage on the 204 is monitored. The sensor
supply voltage is displayed in the
INFO
menu
(s. 10). Some sensors, however, will only oper-
ate properly with their own supply voltage; this
may require e.g. a mains unit. To prevent mea-
suring errors the minimum sensor voltage
needed by each individual sensor can be en-
tered in 'sensor programming'. If the sensor voltage drops below this value the
measured value will be treated as a sensor breakage and display 'L' flashes
see 9.2).
To enter the minimum sensor supply voltage
U-Sensor Min: 12.0 V
To disable voltage monitoring, to clear the value
<CLR>
U-Sensor Min: ---- V
15.12.5 Output function
If the current measured value of measuring point Mx.x is not actually needed
but only the maximum, minimum, average, or alarm value, this function can be
programmed as output function (see Manual 6.10.4). Saving, analog output,
digital output need then only process the appropriate function value. As verifi-
cation that the output function has been thus changed the measured value is
shown with the symbols listed below (s. 9.2).
Examples:
1. If measured values are being averaged over a cycle the only output value of
interest is the average value itself, not the last measured value. When sim-
ply recording data this approach saves memory capacity.
2. The analog measured value from dew sensor FH A946-1 is not really signif-
icant. If limit value - maximum is set to approx. 0.5 V and the alarm value
52 ALMEMO
®
204
* SPECIAL FUNCTIONS 1 *
Connector: M0 Channel: 0.0
U-Sensor Min:
12.0 V
Output function: MESS
Ref. channel 1: (0.0) 2: (0.1)
Elementflags:
-------
Calibration val.: ---------
Mªª Pª
Summary of Contents for ALMEMO 204
Page 72: ...20 Annex 72 ALMEMO 204...
