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Preface
The following manual describes the 70E/70M Pressure Boosters with emphasis on the new micropro-
cessor based Technologic Controller. This unit is in the tradition of the other members of the Technologic
Control Panels as it incorporates many original, novel, and proprietary features that may only be found on
B&G controllers. Some of these features require special emphasis here.
The controller is best described as a specific purpose programmable pump controller. This means that
the hardware and software have been created for the control and diagnostics of pumps with considera-
tion for their inherent characteristics. This results in an optimum pump controller without the cost of gen-
eral purpose control hardware. Software is dedicated and established for the unit only after extensive
testing. Changes to this software are not taken lightly and must pass rigid version control.
The controller has the unique patented analog input protection of other members of the control family.
Upon inadvertent higher than normal input voltage the analog input resistor is sacrificed. An on-board
spare is used to replace the plug-in resistor. Extreme hi-voltage is protected against by additional
components.
Unique to this new controller are virtual selector switches. Microprocessor control coupled with discrete
logic allows the pump keys to act as 3 position selector switches. The 3 positions are hand-off-auto.
Virtual selector switches surpass standard selector switches in that they can be changed from auto to
hand automatically upon a fault in order to maintain a process. It is novel that just as a standard selector
switch can change position (by human hand) with power off, so can the virtual selector switch similarly
change position.
Combined with the virtual selector switches is redundant control with discrete logic which is activated
upon a microprocessor fault. This is explained in detail in Section 5.4.
In addition to this unique hardware the controller has provision for three 4-20mA analog signals and two
RTD temperature inputs. Bell & Gossett is able to offer suction, system, and temperature inputs as stan-
dard. The third 4-20mA is used for an optional flow transmitter.
Bell & Gossett is thereby able to offer staging of pumps by any one of 4 methods, i.e.: watts, amps, PSI
and GPM (flow). The main changes occur in the menu entries.
Staging by watts is standard. A power transducer of Bell & Gossett design is included. This transducer is
factory calibrated, single conductor sensing, wide current and voltage range, and automatic adaptability
to Wye or Delta systems either grounded or ungrounded. At the customer's discretion it may be used for
amp staging with the watt feature used to display total system power.
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