Delta RowCool HCH1CB0, User Manual, Page: 34 / 128

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InfraSuite RowCool Precision Cooling –
Chilled Water
P I D
9.00 0.55 0.000
y
Adjustment procedures
The adjustment is made based on an open circuit method as follows:
1
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high, medium, and low openings of the three-way ball valve from the control panel.
2
Adjust the three-way ball valve to the opening at half of the rated flow rate, which
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opening is too large (above 70%), reduce it to a medium opening (about 50%).
3
When the temperature and humidity of outlet air and return air are stable, record the
readings of time-dependent outlet air temperature and observe if the inlet and outlet
water temperatures are stable.
4
Use the control panel to start the manual mode and increase the opening (above
75%). Due to the internal delay of the system, the outlet air temperature will change
with the time.
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6
Calculate the best PID values in different modes in accordance with the following
table.
Mode Gain Reset Derivative
P
WDX7G[*
PI
WDX7G[*
0.3/ Td
PID
WDX7G[*
0.5/ Td 0.5 Td
*
(response gain): it varies with opening values and therefore, the medium opening or the opening
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7
The I and D values can be found from the Reset and Derivative values.
8
Enter the PID values found on the control panel, start the automatic mode, and make
continuous observation of temperature oscillation. If the temperature is stable, record
the value on a sheet of paper and output the adjusted set values (including supply air
and return air temperature and humidity, fan speed, inlet water temperature, and out-
let water temperature) via the SNMP interface.