82
Commissioning
WAGO-I/O-SYSTEM 750
750-451 8 AI RTD
Manual
Version 1.1.0
Table 63: “Scaling” > “Channel 1 …8” Menu Item
Option
Description
Scaling settings
Enable manufacturer
scaling
Manufacturer scaling is enabled. Manufacturer-side scaling is
applied. The gain multiplier, gain divisor and offset cannot be
entered individually.
Manufacturer scaling is disabled.
Enable user scaling
User scaling is enabled. By enabling user scaling, the gain
multiplier and offset can be specified individually.
User scaling is disabled.
Offset
The offset value moves the zero point of the unscaled process value
(offset on the y axis).
Gain multiplier
The gain multiplier changes the slope factor of the unscaled process
value.
Gain divisor
The gain divisor determines the resolution of the gain multiplier. The
gain divisor is 256 by default.
Process value
The process value is the resistance or temperature value resulting from
the temperature or resistance measurement. The process value is given in
°C or Ohm depending on the sensor type set.
The user has the option of scaling the measured values calculated by the I/O
module. A linear equation is applied to the sensor-specific measurement variable:
•
y2 = ((y1 × Reg40) / Reg41) + Reg39
The variables are assigned as follows:
•
y2= scaled process value
•
y1= unscaled process value
•
Reg40= gain multiplier
•
Reg41= gain divisor = set to 256 by default
•
Reg39= scaling offset
The gain multiplier and scaling offset values are required for user scaling. After
entering both factors, you receive a scaled process value as the result. The gain
divisor determines the resolution of the gain multiplier. The gain divisor is set to
256 by default.
7.2.1.3.3 Application Examples of Scaling
•
Example with the “Pt100 (IEC 751)” setting
How to calculate the scaled process value is described below. The equation for
calculating the scaled process value with the “Sensor type Pt100 (IEC 751)”
setting in standard format with corresponding variables is:
((Unscaled process value × gain multiplier) / 256) + scaling offset = scaled
process value in °C
