Rockwell Automation 57C409 2 Channel Analog Input Module - Manual (Page 15)

3Ć3
Read register 4 to determine whether bits 8 and 10 are set,
signifying that the common clock is being driven by
another module in the rack. If they are not set, then set
registers 5 and 6 on this module to the value 64. This will
enable common clock on this module. Bits 8 and 10 on
register 4 should now be set.
Monitor registers 0 and 1. Verify that they contain numbers
proportional to the analog value on their respective
channels. This confirms that the installation is complete.
Refer to table 1 for the approximate voltages or currents
that should be read.
Table 1
value +1V +10V 4Ć20 ma
ă4095 +1.0V +10.0V 20 ma
ăă819 +ă.2V +2.0V ă4 ma
ăăă0 0.0V 0.0V ă0 ma
-4095 -1.0V -10.0V ă -
Step 9. Determine offset and gain compensation. This is
necessary because manufacturing tolerances on the
module can result in small offset and gain differences (See
figure 3.3).
VOLTS 0
4095
10
COUNTS
CORRECTED_VALUE%
OFFSET
RAW_DATA%
Figure 3.3 Ć Offset and Gain