Resistor Bridge (Strain Gauge) - WAGO 750-489 Manual

102 Process Image
4.9

Resistor Bridge (Strain Gauge)

Standard Format
In strain gauge measurements, the I/O module outputs the measured values as
a process value normalized to 25000.The defined measuring range of
−30 mV ... +30 mV for example corresponds to a possible process value of
−25000 ... +25000.
The voltage values are represented at a resolution that depends on the
measuring range:
• 1 digit per 0.0006 mV (SG - Ud ±15 mV)
• 1 digit per 0.0012 mV (SG - Ud ±30 mV)
• 1 digit per 0.0024 mV (SG - Ud ±60 mV)
• 1 digit per 0.1 mV (SG - Uref +2.4 V)
in one word (16 bits).
Voltage values below 0 mV are represented in binary form as the two's
complement. The voltage underranges and overranges relate to manufacturer
range violations.
S5-FB250 Format
For voltage measurements with S5-FB250 format enabled, the I/O module
outputs the measured values for the sensors normalized to 2500.
The defined measuring range of −15 mV ... +15 mV for example corresponds to a
possible process value of −2500 ... +2500.
Note:
Be aware that the status information is represented in bit 0 ... bit 2 and the
digitized measured value in bit 3 ... bit 15. Therefore, the normalized measured
value is shifted by three bits in the process image!
Thus a normalized measured value of +2500 corresponds to a process value of
+20000.
The voltage values are represented at a resolution that depends on the
measuring range:
• 1 digit per 0.006 mV (SG - Ud ±15 mV)
• 1 digit per 0.012 mV (SG - Ud ±30 mV)
• 1 digit per 0.024 mV (SG - Ud ±60 mV)
• 1 digit per 1.0 mV (SG - Uref +2.4 V)
in one word (16 bits).
Representation in the tables: Corresponding monitoring must be switched
on!
The "Underflow", "Overflow", "Underrange" and "Overrange" areas require that
the corresponding monitoring is switched on (see Section "Diagnostics" >
"Behavior of the I/O Module in the Event of Error").
Manual
Version 1.1.0, valid from FW Version 02
WAGO-I/O-SYSTEM 750
750-489 4AI RTD/TC/Strain Gauge Ex i