Omron SYSMAC C Series Operation Manual page 103

Functions
Averaging and Alarms
5-6-2 Scaling
1, 2, 3...
Input Range: 0 to 10 V
Scaling High: 5000 liters/minute
Scaling Low: 0 liters/minute
BCD
A/D Data
5000
4095
2500
2047
0000
0 V
Input signal range
88
High and low limit alarms are processed before averaging is performed. It is thus
possible that the averaged input data will still be within the set limits even when a
high or low alarm has been given. This can happen when the upper or lower limit
has been exceeded only momentarily, causing the High or Low Alarm Flag to
turn ON even though the average value has not yet (and possibly never will) ex-
ceeded the limits.
The scaling function can be used to perform conversion of data to engineering
units prior to transfer to the CPU Unit. With this feature enabled, the Unit maps
the 0 to 4095 range of the analog input to a new user-specified range. The range
can have upper and lower limits anywhere in the range –32768 to 32767 (binary)
or –7999 to 7999 (BCD). Scaling can even be used to accomplish a sign inver-
sion by setting the lower scale value positive and the upper scale value negative.
Examples 1, 2, and 3, illustrate scaling:
Example 1: Scaling 0 to 10 Volts to Engineering Units (0 to 5,000 l/min)
Input point 1 of the Unit is connected to a 0 to 10 V signal from a flow sensor in a
pipe. It has been determined that a 0 V reading on the sensor indicates no flow in
the pipe and a 10 V reading on the sensor indicates 5,000 liters/minute.
To configure the Unit to report the data in percentage full:
1. Set the scaling low and high limits to 0 and 5000.
2. Turn ON the scaling enable bit for input point 1.
Binary
(Hex)
Scaling Data
Normal Data
5 V 10 V
A/D Data
1388
0FFF
09C4
07FF
0000
0 V
Input signal range
Section
Scaling Data
Normal Data
5 V 10 V
5-6