Ecotech Serinus 40 - Digital Pots; Control Loop

Operation
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Control Loop
When Enabled the instrument will control all processes within the
instrument.
Selecting Disabled pauses the instrument control over certain
processes and parameters (e.g. digital pots). The user can now
manually alter and adjust digital pots without the microprocessor
overwriting the changes.
Note: Turning off the control loop will disrupt normal
measurement.
Cooler Duty Cycle
This number represents how hard the PMT cooler is driven. So if
the value is between 0.9-1, then the cooler is being driven hard. If
the value is around 0.5 then the cooler is been driven normally.
Note: During start-up the cooler duty will be close to 1 but once it
reaches the 13°C set point it should reduce to around 0.5
depending on the enclosure temperature.
3.5.16 Digital Pots
Pots are electronically controlled digital potentiometers used for adjustments to operations of the
analyser. This menu should be accessed only during diagnostics.
Unless the control loop is turned off (refer to Section 3.5.15), changes to the pots may be modified
by the microprocessor. This is intentional; some diagnostics are best done with instrument feedback,
and some are best done with the instrument inactive.
Table 4 – Digital pots
Digital Pot
Normal
Range
Description
High Volt Adjust
(130-150)
Allows adjustment of the PMT high voltage supply.
High Voltage
(640-670)
The voltage applied to the PMT.
PGA Gain
(1-128)
Displays gain of the Programmable Gain Amplifier (used to boost
the concentration voltage before the analog to digital converter).
Input Pot
(104)
Input gain – only part of the raw signal is fed into the analog to
digital converter.
Conc Voltage (RAW)
(0-3.1)
The concentration voltage measured by the analog to digital
converter.
Conc Voltage
(0-3.1)
The concentration voltage after adjustment for the PGA gain
factor.
Test Pot
(0)
This pot is for diagnostics only.