Choosing High Or Low Set Points; Selecting A Hysteresis (Dead Band) Value - EUTECH INSTRUMENTS ALPHA CON 1000 CONDUCTIVITY CONTROLLERTRANSMITTER (REVISION 3) Instruction Manual

Operating Instructions
7.3.3

Choosing High or Low set points

Select a low set point to activate controller when the conductivity value undershoots the low set point;
select a high set point to activate controller when the value overshoots the high set point. Using both
SP1 and SP2, you can select lo/lo, lo/hi, hi/lo, or hi/hi set points (Default: SP1 = Lo; SP2 = Lo).
1) Follow directions in 7.3.1 to enter Control Relay mode.
2) Press the ENTER key. Scroll with the ▲ or ▼ keys until the upper display shows Lo or Hi (for
low or high set point) and the lower display shows SP1 (or SP2).
3) Press the ▲ or ▼ keys to select low (lo) or high (hi) set point for SP1 (or SP2).
4) Press the ENTER key to confirm your selection.
5) Proceed to 7.3.4, or return Measurement mode by pressing the ▲ and ▼ keys simultaneously
(escape).
7.3.4

Selecting a hysteresis (dead band) value

Hysteresis prevents rapid contact switching if your value is fluctuating near the set point. It does this
by overshooting the set point value to a specified hysteresis value
Example: You have set your set point 1 (Lo) at 100.0 µS and your hysteresis limit value is at 20 µS. If
your measured value undershoots the low set point of 100.0 µS, the controller's relay activates, which
in turn activates an external device such as a pump or valve. The actions of the external device will
cause the value to rise above 100.0 µS. When the value has increased to 120.0 µS, the relay, and
hence the pump will switch off.
Default hysteresis value in the full scale conductivity range of 2,000 µS (see Appendix 2) is 20 µS.
You can set the hysteresis value from 0 to 10% of the full scale conductivity range.
1) Follow directions in 7.3.1 to enter Control Relay mode.
2) Press the ENTER key. Scroll with the ▲ or ▼ keys until the
upper display shows the hysteresis (dead band) value and the
lower display shows "HYS".
3) Press the ▲ or ▼ keys to enter your hysteresis value for Set
point 1 (or Set point 2). Your controller will activate at the value
you select. Note: All settings for SP1 and SP2 are completely
independent of each other.
4) Press the ENTER key to confirm your selection.
5) Proceed to 7.3.5, or return to Measurement mode by pressing the ▲ and ▼ keys
simultaneously (escape).
NOTE: Please refer to Appendix 3 for a graphical representation of the Hysteresis.
15
αlpha-CON1000
HOLD SETUP
20
Hys
6
µ
S