Allen-Bradley 857-RAA, User Manual

Page: 25 / 42

Rockwell Automation Publication 857-UM002C-EN-P - February 2018 25
Configure the Base 857 Relay Chapter 4
These scaling factors shift the measured value’s decimal point to either left or
right so that accuracy of the measurement is decreased or increased. This is
done when the relationship between the parameters are in factors of 10. See
857-PM001 for further details regarding scaling.
Figure 11 - X1, X2, Y1, Y2 Scaling
See Table 8 for the valid values for the parameters “AI Enabled”, “AI Unit”, “AI
Slave Address”, “AI Modbus Address”, “AI Register Type”, “AI Signed”, “AI
Offset” and the X1, X2, Y1 and Y2 ranges setting that can be adjusted within
the External Analog Input-Quick Setup field in SetPointPS.
When External I/O-protocol selection is RTDinput, the AI Slave Address, AI
Modbus Address, AI Register Type and AI Signed can be left to their default
values.
Table 8 - Parameter Values and Description
Parameter Value Explanation
AI Enabled On Particular AI enabled
Off Particular AI disabled
AI Slave Address Settable value (1 – 247) Address of the 857-RAD (address set with DIP
switches)
AI Modbus Address Value (1 – 9999) Modbus RTU registers. Relay sets these
according to the selected device type.
AI Register Type HoldingR Modbus RTU register type. Relay sets these
according to the selected device type.
InputR
AI Signed On Relay sets these according to the selected
device type.
Off
AI Offset Settable value (-32000 thru 32000) Used to adjust the measured value
throughout the range.
x1, y1, x2, y2 Settable value (-32768 thru 32768) Scaling values. X1 and X2 are the minimum
and maximum modbus values. Y1 and Y2 are
the minimum and maximum values