Bell & Gossett S12596B Technologic 350 Pump Controller - Manual (Page 3)

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PREFACE
The following manual describes the new microproces-
sor based Technologic 350 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 con-
trol and diagnostics of pumps with consideration for
their inherent characteristics. This results in an opti-
mum pump controller without the cost of general pur-
pose 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 auto-
matically 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 redun-
dant 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 four 4-20mA analog signals and two RTD
temperature inputs. Bell & Gossett is able to offer pres-
sure (1PT, 2PT) and temperature inputs (T-1, T-2) as
options. The third 4-20mA is used for an optional flow
transmitter. The fourth 4-20mA is for optional tempera-
ture transmitter.
Bell & Gossett is thereby able to offer staging of pumps
by any one of 6 methods, i.e.; watts, amps, PSI and
GPM (flow), temp and Delta T. 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 cur-
rent 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 sys-
tem power.