-
- Calibrate
- Adjusting instrument for proper response.
-
- Calibration
- The comparison of a measuring device (an unknown) against an equal or better
standard. Test during which known values of Measurand are applied to the device
under test and corresponding output readings are recorded under specified
conditions.
-
- Calibration Curve
- Graphical representation of the calibration record.
-
- Calibration Cycle
- the application of known values of Measurand and recording of corresponding
Output readings over the full or the specified portion of the Range, in an
ascending and descending direction.
-
- Calibration Offset
- An adjustment to eliminate the difference between the
indicated value and the actual value.
-
- Capacitance
- Change in energy or material required to make a unit change in a measured
variable.
-
- Capacitance Cs, Cause of Change
- - Proximity to conductive objects
If an object
of conductive material is located within the sensing
distance of the sensor, it will form two series connected
capacitances with sensor areas S and M. The series connected
capacitances are much larger than the capacitance of the
undamped oscillator. Maximum sensing distance can be
achieved with conductive objects like metals, water etc.
- - Of non-conductive objects
If a non-conductive
object is moved into the sensor field, the field will be
amplified in relation to the relative permittivity (Er) of
the material to be detected and thus increase capacitance
Cs. As from a relative permittivity of Er = 81 (water),
sensing distances can be achieved that are equivalent to
those for conductive materials. The sensing distance is
reduced for materials with a lower Er.
| Material |
Relative
Permittivity (Er) |
Material |
Relative
Permittivity (Er) |
| Air, Vacuum |
1 |
Wood |
2-7 |
| Paper |
1.2 - 3 |
Marble |
8.4 - 14 |
| Paraffin Oil |
2.2 |
Alcohol |
25 |
| PVC |
3 |
Methanol |
33.5 |
| Glass |
3-5 |
Water |
81 |
-
- Capacitive Load
- Leading load; predominantly capacitive, so voltage does not change direction
until corresponding current does.
-
- Capacitive Sensors
- Sensing technique which uses the capacitance of a target
(can be clear glass or liquids) to switch an output.
-
- Capacitor
- Circuit device that can store an electric charge. A typical capacitor has 2
conductors or electrodes separated by a layer of non-conducting material
(dielectric). With conductors on opposite sides of the dielectric layer,
oppositely charged by a source of voltage, the electrical energy of the charged
system is stored in the polarized dielectric.
-
- Cascade
- (a) To combine logic circuitry to get more complex logic or timing control.
(Inputs and outputs are wired in series.) (b) Two or more controllers working
together. The output of the master controller is the set point for the "slave"
controller. A classic example is the control of a reactor (a large vessel with a
steel jacket around it). The product temperature (master) controller's output is
the setpoint of the jacket temperature (slave) controller.
-
- Cascade Control
- Control action where the output of one controller is setpoint of another
controller. Can be used in a controller using two loops of control.
-
- Catalyst
- A substance that changes the rate of a chemical reaction but is itself not
changed. Switch contact material sometimes acts as a catalyst, accelerating the
formation of polymers on the contact surface.
-
- Cathode
- The switch contact connected to the negative terminal of the power supply.
-
- CE
- A manufacturer's mark that demonstrates compliance with
European Union (EU) laws, primarily governing products sold
in Europe.
-
- CE-Compliant
- Compliant with the essential requirements of European
directives pertaining to safety and/or electromagnetic
compatibility.
-
- Celsius
- Formerly known as Centigrade. A temperature scale in
which water freezes at 0°C and boils at 100°C at standard
atmospheric pressure. The formula for conversion to
Fahrenheit scale is: deg°F = (1.8*deg°C) + 32.
-
- CENELEC
- This is a European standards committee, similar
to UL or NEMA. It covers standardized dimensions and
operating characteristics.
-
- Chatter
- The rapid On-Off cycling of an electromechanical relay
or mercury displacement relay due to insufficient controller
bandwidth. It is commonly caused by excessive gain, little
hysteresis, and short cycle time.
-
- Chip
- A die (unpackaged semiconductor device) cut from a silicon wafer,
incorporating semiconductor circuit elements such as resistors, diodes,
transistors, and/or capacitors.
-
- Clean Air
- Ideal conditions. Climate-controlled or sterile area.
-
- Clock Frequency (SSI)
- For absolute encoders with synchronous serial interface
(SSI), the clock frequency is the frequency of the clock
signal during data transmission. The clock frequency is
specified by the sequence electronics, and must be within
the corresponding limits.
-
- Clock + / Clock -
- Control lines of the SSI interface for synchronous data
transmission. Clock+ and clock- together form a current
loop, for potential-free reception of the clock frequency in
SSI encoders.
-
- Close Range Shielding
- The capacitive sensor responds to all materials whose
relative permittivity Er is greater than 1 (air, vacuum).
This means that dirt deposits and moisture on the sensor
surface are also detected.
-
- Closed Loop
- Complete signal path in control system; represented as group of units
connected in a manner that signal started at any point follows closed path and
comes back to that point. Signal path includes forward path, feedback signal,
and summary point.
-
- Closed Loop Control
- A control system in which all adjustments necessary to
maintain the system occur automatically through a feedback
signal from the sensor.
-
- Code Reader
- A code reader contains up to 6 identical inductive
sensors. Advantage: common supply rail, quick installation,
reduced distance between individual sensors, very compact
-
- Code Switching Speed
- Number of measuring steps per second for absolute
multi-turn encoders. For encoders with 13 bit resolution and
400 kHz code switching frequency, the maximum rotational
speed is 3,000 rpm.
-
- Co-generation
- The term used to express the simultaneous production of two useful forms of
energy from one process, i.e. steam used to produce electricity and provide for
space heating in the same process.
-
- Cold Junction
- Connection point between thermocouple metals and the
electronic instrument.
-
- Cold Junction Compensation
- Electronic means to compensate for the effective
temperature at the cold junction.
-
- Color Sensors
- With the color sensor, you can use color as the criteria
for sorting, quality monitoring and automation processes.
-
- Common Mode Rejection (CMR)
- The ability of an electronic device to eliminate the
effect of AC or DC noise between signal and ground. Normally
expressed in dB at DC to 60Hz. See also Normal Mode
Rejection.
-
- Communications Address
- Number assigned to instrument used in data message exchange.
-
- Compensation
- Procedure of providing a supplemental device, circuit, or special materials
to counteract known sources of error (e.g., ambient temperature change).
Compensation is often related to temperature compensation only.
-
- Complementary Output
- Both N.O. and N.C. outputs are available for use. A circuit that provides
sink or source capability with a single input. Output that can be both light
operated and dark operated. (Also known as 4-wire DC controls.)
-
- Composition
- A process variable that represents the amount of one material in a solution,
or gas.
-
- Condensate
- When steam cools it first transitions to water vapor and then back into
liquid water, the condensed liquid is called condensate.
-
- Configuration
- Dedicated operation; keystroke sequences select and establish pertinent
control data best suited for an application.
-
- Connection Cables
-
For shaft encoders, equipped with a
connector base, the appropriate connector can be ordered as
an accessory. For encoders with cable connection, the
standard length of cable provided is 2 m respectively 1 m.
The sheathing material for the incremental encoder is PUR.
The wire size is 0.14 mm2. The cable screen is connected to
the housing respectively to the flange. The operating
temperature range is -20°C to +85°C.
Permissible bending radius at 20 °C: cable
with a PUR sheath 12x cable ø
- Control Cycle
- The rate at which the output signal is updated.
-
- Control Action
- Nature of change of output affected by input. Output can be signal or value
of a manipu-lated variable. Input can be an actuating error signal, output of
another controller, or control loop feedback signal when setpoint is constant.
-
- Control Base
- Unit remote from sensor in which amplification and conditioning of the input
signal takes place. Usually contains a power supply and an output device.
-
- Control Mode
- Designates the mode in which controller will operate (such as Manual,
Automatic with Local Setpoint, Automatic with Remote Setpoint, Manual Cascade).
-
- Control Point
- Value of controlled variable that you operate to maintain.
-
- Controlled Variable
- Quantity or condition of controlled medium that is measured and controlled.
-
- Controller
- Device that measures changes in controlled variable and indirectly maintains
the controlled variable within present limits.
-
- Controller Output – CO
- Output signal from the controller.
-
- Convergent Beam
- A variation of the diffuse scanning mode. A photoelectric control whose
optical system is key to its operation. It simultaneously focuses and converges
a very small, intense beam to a fixed-focal point in front of the control. The
control is essentially blind a short distance before and beyond this focal
point. Convergent beam scanning is used to detect the presence or absence of
small objects while ignoring nearby background surfaces.
-
- Convertible Output
- Output that can be wired either as Normally Open or Normally Closed, but not
at the same time.
-
- Corner Frequency
- For first order time constants, the "corner frequency" is the frequency
where the amplitude ratio starts to turn and the phase lag equals 45 degrees.
-
- Corrective Factor
- Mathematical factor that, when multiplied by the sensing distance of a given
sensor, will adjust sensing distance for the different metals being used as
targets.
-
- Couplings
- The most suitable flexible coupling can be chosen from
the data of a servo drive system. Resolution, acceleration
and the desired positional precision must be considered. The
lag angle can be judged from the torque stiffness. This
torque might be considerable, if high dynamic drive systems
are used. The inertia moment is specified on the product
data pages.
-
- CSA
- Canadian Standards Administration
-
- Current
- Time value of movement of free electrons. One ampere equals one coulomb per
second. Conventional reference is opposite to direction of actual electron
movement.
-
- Current Consumption
- Amount of current required to power a sensor or control (excluding load).
See supply current.
-
- Current Duplex
- Control algorithm that provides a second current output (split range) or
second current output via auxiliary output for heat cool zones.
-
- Current Sinking
- Output type such that when it is On, current flow is from the load into the
device's output, then to ground. Output is Normally High. The sensor "sinks"
current from the load through the sensor to ground. The load is connected
between the positive lead of the supply and the output lead of the sensor.
-
- Current Sourcing
- an output type such that when it is On, current flow is from the device into
the load. Output is Normally Low. The sensor "sources" current to the load. The
load is connected between the output lead and the negative ground lead of the
supply.
-
- Current/Time Duplex
- Variation of duplex with current active for 50% output and relay active for
50% output.
-
- Cycle Time
- Length of one time-proportional output relay cycle. The time, usually
expressed in seconds, for a controller to complete one on/off cycle.
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