Hach-Lange SC 1000 - Manual (Page 88)

86
Advanced Operations
The output value (OV) is determined according to formula (4) :
where:
OV=Output value
IC=Input current
LV=Low value
HV=High value
6.3.3 Relay menu
Note: This menu appears only if a relay card is installed in the sc1000 controller.
The relay menu content for a relay card depends on the selected working mode. There
are several relay card working modes:
ALARM
Relay controls if a process value is between two limits.
Figure 54 Output value with an input range of 4 – 20 mA
1 Output value (concentration) (y-axis) 5 4 mA
2 OV=f(IC) 6 0 mA
3 Input current (x-axis) 7 Low value (LV)
4 20 mA 8 High value (HV)
(4) OV = f(IC) =
HV – LV
× (IC – 4 mA) + LV
16 mA