Rockwell Automation 1715-OF8I Redundant I/O System User Manual - Manual (Page 146)

146 Rockwell Automation Publication 1715-UM001C-EN-P - March 2014
Chapter 4 Using 1715 Analog I/O Module Features
These examples are instances where you can need to use module inhibiting:
• You want to upgrade an analog I/O module. We recommend you do the
following.
a. Inhibit the module.
a. Perform the upgrade.
b. Uninhibit the module.
• You are using a program that includes a module that you do not physically
possess yet, but you do not want the controller to continually look for a
module that does not exist yet. In this case, you can inhibit the module in
your program until it physically resides in the proper slot.
Scaling The limits field is a variable that lets you to set the channel output current values
based on a scaling factor. You set the minimum and maximum output values by
using the scaling factor. The scaling factor requires you to set a percentage of the
engineering values. This gives a linear transformation between the engineering
values and the output scaled values across the defined range.
The default minimum and maximum values are 0% equals 4 mA and 100%
equals 20 mA.
Regardless of the Limits field settings, the output current is clamped at
0…24 mA maximum.
The module can operate with values beyond the 4…20 mA range. If an input
signal beyond the low and high signals is present at the module (for example,
3mA), that data is represented in terms of the engineering units set during scaling.
Table 23 shows example values that can appear based on the example mentioned
above.
Table 23 - Current Values Represented in Engineering Units
Current Engineering Units Value
4 mA 0%
12 mA 50%
20 mA 100%