5
LIFO / FIFO ADJUSTMENT
The R851V series features 2 different staging sequences:
•
LIFO
LAST IN FIRST OUT ( CONTROL SWITCH #1 OFF, FACTORY DEFAULT )
This is the regular mode. Stage #1 will always be the first to energize and the last stage to de-energize
•
FIFO
FIRST IN FIRST OUT ( CONTROL SWITCH #1 ON )
In this mode, the stages are rotated to ensure a more uniform wear of the contactors and elements. For example, on an increase in
demand, stage 1 will be energized following by stage 2, etc. On a decrease in demand, stage 1 will de-energized first followed by
stage 2, etc.
Please verify that if this mode is enabled, the manufactured product still complies with active codes and regulations.
VERNIER STAGE SELECTION AND WIRING
The Viconics R851V series step controller has an integrated vernier control output. This output will give a precise and full
modulation of the load from 0 to 100% of the total capacity of the unit. If a master slave application is used, always connect the
vernier output of the master unit.
ADJUSTMENTS
Functions of the units can be configured with six dip switch and 2 potentiometers.
0 to 9 min.
5 to 60 sec.
Interstage delay potentiometer setting
Two potentiometers are used to adjust the interstage delay from 5 seconds up to10 minutes.
This delay is active in 3 ways.
•
Minimum time delay between each step activation when the control signal rises
•
Minimum ON time when the step is activated
•
Minimum time delay between each step de-activation when the control signal drops
Vernier stage ratio
A potentiometer is used to adjust the vernier stage ratio from 100% to 200% capacity of the other on/off
stage capacity.
RATIO SETTING
( See also slave application section at the end )
First adjust the vernier stage ratio potentiometer. This will insure a smooth capacity rise of the total load.
Example 1:
The total unit has 100 kW divided in 10 equal stage of 10 kW.
If only 10 kW is used as the modulating stage, then the heater would have 9 on/off mechanical stage plus
one modulating stage. This modulating stage has the same value as all the other stage.
Adjust the vernier stage ratio
potentiometer to 100%.
Example 2:
The total unit still has 100 kW divided in 10 equal stage of 10 kW.
If 20 kW are used as the modulating stage, then the heater would have 8 on/off mechanical stage plus one modulating stage.
The modulating stage has twice the value as all the other stage.
Adjust the vernier stage ratio potentiometer to 200%.
•
TYPE OF VERNIER STAGE SETTING
The vernier stage output can be configured to operate either as a:
•
Vdc pulsed output to activate an R810 power module
•
0 to 10 Vdc analog output to activate an R820 SCR power controller.
RATIO(%)
100
200
150
VR2
100
200
150
125
175
