Instruction Manual alpha-pH 1000
20
7.3
Control Relay A/Control Relay B (SP1/SP2) sub-function
The SP1 option sets the operating parameters for Relay A; the SP2 option sets the operating parameters for
relay B. Since these groups have the same set-up parameters, they are described together.
7.3.1
Entering the Set point 1 (Set point 2) sub-function
1)
Enter Advanced Set-up mode
. Push the ENTER key and scroll to
Advanced Set-up security code “22”. Push the ENTER key again.
2)
Press the
▲
or
▼
key
to scroll until the upper display shows SP1
(SP2).
7.3.2
Selecting the set point values
This lets you choose the value that will cause your controller to activate
(i.e. pH 9.0).
1)
Follow directions in 7.3.1
to enter Control Relay mode. If you are
in this mode, skip to step 2.
2)
Press the ENTER key
. The upper display shows the current set
point value and the lower display shows SP1 (SP2).
3)
Press the
▲
or
▼
key
to enter your value for Set point 1 (Set
point 2). Your controller will activate at the value you select.
4)
Press the ENTER key
to confirm your selection.
5)
Proceed to 7.3.3 step 3, or return to Measurement mode by
pressing the
▲
and
▼
keys simultaneously (escape).
7.3.3
Choosing High or Low set points
Select a low set point to activate controller when the pH/ORP 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.
1)
Follow directions in 7.3.1
to enter Control Relay mode.
2)
Press the ENTER key
. Scroll with the
▲
or
▼
key until the upper display shows Lo or Hi (for low or high
set point) and the lower display shows SP1 (SP2).
3)
Press the
▲
or
▼
key
to select low (lo) or high (hi) set point for SP1 (SP2).
4)
Press the ENTER key
to confirm your selection.
5)
Proceed to 7.3.4 step 3
, 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. You can set the hysteresis value from 0.1 to
1.0 pH, 10 to 100mV or 1 to 10%.
Example: You have set your high set point at pH 9.0 and your hysteresis limit value at pH 0.5. If your measured
value overshoots the high set point pH 9.0, the controller’s relay activates, which in turn activates an external
devices such as a pump or valve. The actions of the external device will cause the solution’s pH to drop. When
the pH drops to 8.5 pH, the relay and hence the pump will switch off.
SP1
SETUP
HOLD
Lo
SP1
SETUP
HOLD
4.00
pH
SP1
SETUP
HOLD