ABB ACQ80 Firmware Manual page 71

In addition, 10% of the dead-band value is added as dead-band hysteresis
positive and negative. This value is internally set in the firmware and cannot be
changed.
AI Hysteresis =
Notes: AI dead-band (12.110) is applicable for both AI1 and AI2.Example of using
dead-band in AI1 (voltage mode)
If,
12.15 AI1 unit selection
12.110 AI dead band
= 0 - 10 V
12.18 AI1 max
then,
AI dead-band value = 10 * 50 * 0.01 = 5 V
AI Hysteresis value = 5 * 0.1 = 0.5 V
Hysteresis positive value = 5 + 0.5 = 5.5 V
Hysteresis negative value = 5 - 0.5 = 4.5 V
When AI1 input voltage increases, up to 5.5 V, the AI1 actual value (12.11)
displays zero. After AI1 input voltage reaches 5.5 V, the AI1 actual value displays
5.5 V and continues to display the detected value up to the maximum AI1
value10 V (12.18).
When AI1 input voltage decreases, the AI1 actual value displays the detected
value up to 4.5 V. From 4.5 V to zero, the AI1 actual value displays Zero till it
reaches 0V.
Example of using dead-band in AI1 (current mode)
If,
12.15 AI1 unit selection
12.110 AI dead band
= 0 - 20 mA
12.18 AI1 max
then,
AI dead-band value = 20 * 50 * 0.01 = 10 mA
AI Hysteresis value = 10 * 0.1 = 1.0 mA
Hysteresis positive value = 10 + 1.0 = 11.0 mA
Hysteresis negative value = 10 - 1.0 = 9.0 mA
AI dead-band value
= V
= 50
= mA
= 50
×
10%
Program features 71