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Watlow CLS200, MLS300 and CAS200 User Manual

Page 90

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84 Communications Specification

Glossary

Deadband,
alarm

The range through which a process variable must travel from the alarm
setpoint toward the process setpoint before an alarm clears.

Derivative
control action

A control action in which the output value is proportional to the rate of
change of the error between the process variable and setpoint.

Deviation
alarm

The deviation alarm value is an absolute value that is always relative to
the setpoint. The process is in Alarm in the following cases:
Above (setpoint + deviation value)
Below (setpoint – deviation value)

Device address

The communications address assigned to the controller or host software.

DLE

Data Line Escape. An escape code that signals that a control code follows
it.

Double-bit
error

An error in which two bits in a packet are incorrect.

Duplex, full

Communications in which each node can simultaneously transmit and
receive.

ENQ

Enquiry. A control code that the software sends to the controller, asking it
to resend the last ACK or NAK.

ETX

End Text. A control code that signals the end of a transmission.

Gain

The parameter that users can alter through host software to set the propor-
tional control action. The gain is a unitless number that is inversely pro-
portional to the proportional band. (See also Proportional Band)

Hexadecimal
numbers

Numbers in base 16 where each digit has one of 16 possible values (0 to
F).

Integral
control action

Control action in which the output is proportional to the time integral of
the difference between the setpoint and process variable. (In other words,
the rate of change of the output is proportional to the input.)

Job

A set of operating conditions (setpoints, alarms, PID constants, etc.).

Linear input

Watlow Anafaze controllers have an optional linear input type that allows
you to scale raw input readings to the engineering units of your process.