Thermo Scientific ALPHA DO 2000 PG POLAROGRAPHIC DISSOLVED OXYGEN CONTROLLER TRANSMITTER, Manual

Page: 50 / 56

Instruction manual
Alpha
DO 2000
11.3 Appendix 3 – Simple Explanation on the Function of
Hysteresis
4.00
RELAY OFF
Forward Direction
Reverse Direction
SP1
SP2
RELAY ON
SP1 = 4.00 mg/l & Set to LO
SP2 = 6.00 mg/l & Set to HI
Mg/l
4.20 5.80 6.00
HY
S
T
E
R
E
S
IS
B
A
N
D
D
e
fa
ul
t =
0
.2
m
g
/l
HY
S
T
E
R
E
S
IS
B
A
N
D
D
e
fa
ul
t =
0
.2
m
g
/l
The controller relay activates when the set-point is reached. In the reverse
direction, it does not de-activate when the value reaches the set-point.
Instead, it continues to be active till the value reaches the amount set by the
Hysteresis band.
42