dl/dt function:
The function monitors the size of the decrease or increase (dl) of the input within
a set period of time (dt). If the set ratio, i.e. change per time unit, is exceeded,
the relays will be activated. A time constant can be selected for the averaging of
the input value.
Comparator with an external setpoint:
The process value is compared to the external setpoint, and if the two signals
differ, a relay will be activated, i.e. the UP relay for process values larger than the
setpoint plus a ½ neutral zone, and the DOWN relay for values below the setpoint
minus a ½ neutral zone.
Trip amplifier with an external setpoint:
The relay function can be selected for increasing / decreasing or window. As a trip
amplifier the relays can be activated individually when the input value differs from
the setpoint plus or minus the neutral zone. The window function activates a relay
when the process value differs by more than the neutral zone from the setpoint.
The two relays can be activated independently by a common setpoint.
Output:
2 relay outputs with a make contact connected to a common point.
Relay outputs can be installed in PELV/SELV circuits.
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Functions:
PID on/off controller:
Accurate setting of the regulation parameters XP (proportio
nal band), TI
(integrating time) and TD (differentiating time), with the units selected as XP %,
TI s and TD s. Minimum XP is 0.01% equivalent to a gain of 10,000. By setting
TI and TD to 0, the function will be a pure proportional controller. The controller
adjusts the time interval between the pulses on the output, the pulse width is set
by the parameter TP. When the process value is outside the proportional band,
the output gives a constant up / down signal until the process value is brought
within the proportional band. Hereafter the output pulses with a varia ble interval
depending on the distance from the setpoint. The neutral zone is an accepted
deviation in relation to an ideal output value, where no function is required on the
output. The neutral zone is set in %. The setpoint can be selec ted as internal
(external set point input disabled) or as external (current / volt age).
PI step controller:
The PI step controller is especially suitable for control of motor-driven
valves, throttle valves and dosage units. When the process value is outside
the proportional band, the output will give a constant up / down signal until
the process value is brought within the proportional band. Hereafter the output
pulses with a variable OFF time depending on the distance from the setpoint.
A selec ted minimum ON time protects the motor against too short activations.
The regulation parameters are XP (proportio nal band), tAU (exponential average
time of the active relay state) - functions as inte grating time, tP (the shortest
active time of the relays) and nEU (neutral zone) - the band that the process is to
be kept within. The setpoint can be selected as internal (external set point input
disabled) or as external (current / voltage).
3-band controller:
The neutral zone is an accepted deviation in relation to the setpoint where no
function is required on the output. The neutral zone is set in % of the input span
and centered around the setpoint. If the process input drops below the neutral
zone, the UP relay is activated until the process input rises to the setpoint value.
Similarly the DOWN relay is activated if the process input rises above the neutral
zone, and releases when the input signal drops to the set point value. The setpoint
can be selected as internal (external set
point input disabled) or as external
(current / voltage).
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