566-Base Load Step Control

The Caloritech™ 566 Base Load Step Control is made up of a mother board and 1 to 5 output boards, each with 4 outputs, for a maximum of 20 stages. Time delay between stages is independently adjustable for up and down sequencing from 1 to 200 seconds per stage. This step control can operate in base load control mode by receiving a signal from an SCR. It can also operate in standard step control mode receiving process signals directly from a control.

FEATURES

Up to 5 output boards each with 4 outputs for a maximum of 20 stages
Independently adjustable time delay between stages from 1 to 200 seconds
Able to operate in base load control mode with signal from SSR or in standard step control mode with signals directly from a control

Electronic Step Controls
A step control will bring on stages a few seconds apart.
As the process reaches set point, stages will drop out until
the heat required balances the losses. Under steady state
operation some stages remain on and one or two stages
may cycle to maintain straight line control.

Series R851B Step Control
The R851B is frequently used in boiler and duct
heater systems.

Sequence
Selectable: First stage in, last stage out; or first stage in,
first stage out.

Base Load Step Controls
A base load step control is used with a number of
contactors and an SCR. Contactors step on approximately
80% of the load while the last 20% is controlled by an SCR
for very fine trimming.
A temperature control feeds a signal to the SCR. A signal
from the SCR indicating the SCR is at 100% output will
cause the step control to bring on stages. If the SCR is at
zero output, stages will drop out. As long as the SCR is
modulating, base loads are neither added nor dropped out.

566 Series Step Control
The 566 base load step control is made up of a
motherboard and 1 to 5 output boards, each with 4
outputs, for a maximum of 20 stages (as shown above).
Time delay between stages is independently adjustable for
up and down sequencing from 1 to 200 seconds per stage.
This step control can operate in base load control mode
by receiving a signal from an SCR. It can also operate
in standard step control mode receiving process signals
directly from a control.