Sigma - The IC3-SNP Integration Controller does not display negative values correctly.

Issue

Negative values presented to an IC3-SNP Integration Controller are displayed starting at 65535.

Product Line

Satchwell Sigma, Field Devices, Other

Environment

Sigma

Integration Controllers

IAC Controllers

Unifact Controllers

Cause

The IC3-SNP Integration Controller calculates the negative value incorrectly.

Resolution

To overcome this issue it will be necessary to create a new Lookup table and to allocate it to the IC3-SNP Analogue Input object.

1 - In Sigma "System Manager" select "System Setup" and create a new lookup table, using the configuration shown below.

2 - Edit the Analogue Input object to include the new Lookup Table number, select to download the object.

3 - In Sigma "System Diagnostics" download the Lookup Table to the IC3-SNP.

4 - The lookup table shown above assumes that the value being presented is in whole numbers, i.e. a received value of 1 equals 1, but there are instances when the value received may have a *10 factor applied. In this case the lookup table is modified as shown below.

Input         Output
0               0
32767       3276.7
32768      -3276.8
65535      -0.1