Schneider Electric MTN881001 or the SVEA LON I/O Module DR-N 3DIM 1-10V. Output values are not as expected.

Issue

Schneider Electric MTN881001 or the SVEA LON I/O Module DR-N 3DIM 1-10V. Changing the SNVT nviLALampValue_? does not give the expected output.

Product Line

TAC Vista, Satchwell Sigma, SmartStruxure Solution

Environment

MTN881001

SVEA 36237-552

Cause

Changing the SNVT nviLALampValue[i] to the following values, shows the following VDC volt on the analog output:

nviLALampValue Analog output

100.0 1 -  9,94 VDC
80.0 1 -  7.65 VDC
60.0 1 -  6,75 VDC
50.0 1 -  6.25 VDC
20.0 1 -  4.86 VDC
1.0 1 -  3.97 VDC

When nviLALampValue is 50.0 1, the analog output is 6.25 VDC (not proportional) and the minimum analog output value is 3.97 VDC, which does not make sense.
 

Resolution

The module is using a logarithmic behaviour for the 1-10V output as default. This is because the device is mostly used for fluorescent lamps.

You can change the behaviour by using the UCPTadaptationTable in the lamp Actuator object.

UCPTadaptationTable consists of 21 values representing the digits (from 0 to 255) for the output value in steps of 5%. This means:
 

  • first value: 0%
  • second value: 5%
  • third value: 10%
  • ...
  • 21st value: 100%

To get a linear behaviour you should set as follows:

  • first value: 0
  • second value: 13
  • third value: 26
  • ...
  • 21st value: 255