Bell & Gossett S14334B Technologic 5500 Series Variable Primary Pump and Valve Controller - Manual (Page 32)

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The following is a description of the hardware, diag-
nostics, and corrective action to maintain a process
being controlled by the Technologic 5500 Variable
Primary Pump Controller.
NOTE: The following should not be interpreted as
the maximum configuration of this controller, rather
this describes its application as a technologic 5500
variable primary pump controller only.
6.1 Technical Overview
The Technologic 5500 Variable Primary Pump Con-
troller is a micro-processor based dedicated pump
controller unique to and exclusively manufactured by
Bell & Gossett. All aspects of this unit are strictly
proprietary to Bell & Gossett.
6.2 Digital Inputs
The controller has provision for digital inputs with an
operating voltage of 24 VDC. This signal voltage
must be obtained from the 24 VDC power supply
mounted to the subpanel. It is not recommended
that other power sources be used without factory
approval. Customer connections are made directly
to the terminals mounted on the digital input module.
6.3 Digital Outputs
The controller has provision for relay outputs to con -
trol 120 V 50/60 HZ devices. The relays are not
removable. If defective the digital output module
must be returned to the factory for repair. All relays
operate as single pole single throw. Components are
provided to reduce contact arc and extend electrical
life. Customer connections are made directly to the
terminal blocks that are tied to the digital output
module.
6.4 Analog Inputs
Analog inputs are provided for process variables and
optional transmitters. All analog inputs operate at
4-20mA. They must be powered from the 24 VDC
power supply included with the controller.
6.5 Memory
The logic is stored in a non-removable EEPROM chip
which can be updated from the RS-232 program port
on the CPU or from a memory card. The user setup
data is stored in non-volatile memory or fixed RAM.
The fixed RAM requires power to hold the informa-
tion. While the controller is powered up the CPU
controller provides the power to save the user values.
When the controller is powered down a 3V Lithium
battery provides the power to store the user values.
When the battery voltage drops below 2.5 VDC the
controller will display *ALARM*. After pressing the
HELP key the display will indicate # of # Low Battery.
You will have approximately 25 weeks to replace the
battery before losing memory due to an under volt-
age condition during a power loss.
6.6 CPU
The CPU does not require any maintenance, and it
cannot be replaced as a field repair.
6.7 Power Supply
The power supply provides 24 VDC for all digital and
analog signals as well as the CPU. It is specifically
rated only for the controller and other loads should
not be applied without factory approval.
6.8 Protection
Analog inputs - the analog inputs provided on the
Technologic 5500 Variable Primary Pump Controller
must be wired according to the wiring diagram that
shipped with the unit.
Protection - all analog inputs are protected from high
voltage, crossed wiring, etc. A sustained fault will be
limited to 20mA by the current limiting circuit.
Digital Inputs - as long as input power is derived from
the integral 24VDC power supply they are protected.
Digital Outputs - each output shall not exceed the
ratings on the digital output module.
The digital outputs are fuse protected. For the DO721
module, replace with a T 5A H / 250V fuse only. For
the DO 722 module, Replace with a T 3.15A H / 250V
fuse only.
6.9 Instruments and their Use
With the diagnostics described herein, extensive
instruments are not required. However, the instru-
ments used should be quality units to meet the fol-
lowing at a minimum.
Under no circumstances shall any instrument be
used to test any on board components. Especially
risky is an ohmmeter with battery voltage higher than
TTL logic or applied with incorrect polarity.
6.9.1 AC/DC Voltmeter
Input impedance Not less than 10 MEGOHM.
Accuracy - AC ± 2% of Full Scale
- DC ± 3% of Full Scale
Rated circuit to 1000V.
ground voltage
6.9.2 Ohmmeter
Accuracy ± 2.5%
Max open circuit voltage 0.5 V
6.9.3 Milliamp Meter
Accuracy ± 2% of Full Scale
6.9.4 Signal Generator (analyzer) - recommended
The following signal generators are recommended:
Beta calibrator Model 434 20mA signal analyzer,
Altek calibrator Model 334 4-20mA loop analyzer
or Druck UPS III loop calibrator. Either instrument
may be purchased from a Local Process Control
Distributor.
NOTE: If some other instrument is used it must float
above ground, preferably battery powered.
Section 6 - Maintenance