Thermo Fisher Scientific Alpha pH 2000 - Manual (Page 30)

6.4 Control Relay A/Control Relay B (SP1/SP2) sub-function
The SP1 sub-function determines the operating parameters for Relay A;
while SP2 defines the operating parameters for Relay B. Since these groups
have the same set-up parameters, they are described together.
SETUP
HOLD
SETUP
HOLD
SETUP
HOLD
SETUP
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SETUP
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SETUP
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hi
1 2
5 6
3
3
4
ENT ENT ENT
ENT ENT
ENT
ENT P H
SETUP
HOLD
1. Select the “SP1” (Relay A) or “SP2” (Relay B) sub-function, then press
the ENT key.
2. Setting set point value: press ▲ or ▼ key to enter the value for set
point 1 (set point 2) at which your controller will activate. Press the ENT
key to confirm your setting.
3. Selecting relay function: press the ▲ or ▼ key to select the desired
relay function (“LO”= low or “HI”= high). Press the ENT key to confirm
your selection.
Note: This parameter lets you choose the relay function. Select “LO” to
activate the relay when the pH/ORP value undershoots the set point;
select “HI” to activate the relay when the value overshoots the set point.
SP1 and SP2 can be selected as “Lo/Lo”, “Lo/Hi”, “Hi/Lo”, or “Hi/Hi”.
4. Setting a hysteresis value: press the
▲ or ▼ key to select the desired
hysteresis (setting ranges: 0.1 to 1.0 pH, 10 to 100mV or 1 to 10%) for set
point 1 (set point 2). Press the ENT key to confirm your setting.
Note: Hysteresis prevents rapid contact switching if the measured value
is fluctuating near the set point. Please refer to Appendix 3 for a
graphical representation of the hysteresis.
Example: You have set your high set point at pH 10.0 and your
hysteresis value at pH 0.5. If your measured value overshoots pH 10.0,
the controller’s relay activates. The actions of the external device will
cause the solution’s pH to drop. The relay will deactivate, when the pH -
value drops below 9.5 pH.
5. Setting the on-delay time lag: press the
▲ or ▼ key to enter the on-
delay time for set point 1 (set point 2). The controller will delay activation of