Bell & Gossett S14333 Technologic 5500 Series ZoneSav Controller - Manual (Page 25)

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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 ZoneSav controller.
Note: The following should not be interpreted as the
maximum configuration of this controller; rather this
describes its application as a ZoneSav controller
only.
5.1 Technical Overview
The ZoneSav Controller is a micro-processor based
valve controller unique to and exclusively manufac-
tured by ITT Bell & Gossett. All aspects of this unit
are strictly proprietary to ITT Bell & Gossett.
5.2 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 terminal blocks tied to the digital input module.
5.3 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
terminals mounted on the digital output module.
5.4 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.
5.5 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 ALRM. After pressing the HELP
key the display will indicate Battery!. You will have
approximately 25 weeks to replace the battery before
losing memory due to an under voltage condition
during a power loss.
5.6 CPU
The CPU does not require any maintenance, and it
cannot be replaced as a field repair.
5.7 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.
5.8 Protection
Analog inputs - the analog inputs provided on the
ZoneSav 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.
5.9 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.
5.9.1 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
5.9.2 Ohmmeter
Accuracy ± 2.5%
Max open circuit voltage 0.5 V
5.9.3 Milliamp Meter
Accuracy ± 2% of Full Scale
5.9.4 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. The instruments 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 5 - Maintenance