Rockwell Automation 1746-XXXX SLC 500 4-Channel Analog I/O Modules User Manual - Manual (Page 59)

Publication 1746-UM005B-EN-P - June 2004
Testing Your Module 5-5
To test the analog inputs follow these steps:
1. Determine the boundary conditions for the analog module input
channel. For example, if the input channel is connected to a
sensor that has an output range of 1 mA to 5 mA, the boundary
conditions would be 1 mA (lower) and 5 mA (upper).
2. Using the formulas from page, calculate the input decimal values
that should appear in the processor image table when the
boundary conditions are present on the analog module input
channel.
For example, if 1 mA and 5 mA are boundary conditions, the
decimal values would be 819 and 4096.
3. Assuming that the programming device is on–line with the
processor, select the test mode and continuous scan mode
function.
4. Display the data in File 1 (Input Image Table).
5. Change the radix of the display to decimal.
6. If the input channel of the module has been disconnected from
its sensor, attach a voltage source (voltage input) or current
source (current input) to the input and set the source to the
lower boundary condition.
If the input channel is connected to its sensor, set the sensor to
its lower boundary condition.
7. Locate the input channel image data in the image table. The
input image word for the input channel being tested should read
approximately the lower boundary calculated in step 2.
The exact value of the image word is affected by the accuracy of
the analog module and the input sensor. Ensure that the
deviation from the boundary value is within tolerances for the
analog application.
8. If the input channel has been disconnected from its sensor,
attach the voltage source (voltage input) or current source
(current input) to the input and set the source to the upper
boundary condition.
If the input channel is connected to its sensor, set the sensor to
its upper boundary condition.
9. Repeat step 7 for the upper boundary condition.