Viconics R851B User manual

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Innovative Control Solutions For Your Needs
R851B STEP CONTROLLER
WITH INTEGRATED VERNIER STAGE
•Analog 0 to 10 Vdc vernier stage
•8 step models
•Up to 16 stage total with a slave unit
•Test button
DESCRIPTION
The Viconics R851B series step controller is designed for cost
effective, precise modulation of multi
-stage control application. A
common application is a multi
-step electric boiler.
An integrated vernier
control output will give a precise and full
modulation of the load from 0 to 100% of the total capacity.
FEATURES AND BENEFITS
Microcomputer-based design
Accuracy and reliability
Adjustable step-up and step-
down time delay
Tailor to exact application
Adjustable Vernier ratio
Simplifies design of
proportional stage
0-10 Vdc analog Vernier
output
Permits use of SCR power
controller
Up to 16 stages
One product family can handle
all applications
Progressive or linear
sequencing
Increased flexibility
Test button
Quick troubleshooting
MODELS AVAILABLE
The R851
B is available in 1 model
•
R851B-8 8 stage unit
If more than 8 stages are required, the R851B
-8 can be used as a
master unit with another R851B as a slave unit. Adding another unit
can bring the total step number up to 16.
SPECIFICATIONS
Operating conditions:
0°C to 80°C ( 32°F to 176°F )
0 % to 95 % R.H. non-condensing
Relay outputs:
Pilot duty:
-24 - 120 Vac – 720 VA
-240 Vac – 690 VA
Motor load:
-120 Vac – 1 HP
-240 Vac – 2 HP
Vernier stage: 0 to 10 Vdc, 5 mA max.
Input impedance: 0 to 10 Vdc into 10 KΩminimum
Power supply: 24 Vac -15%, +10% 50/60 Hz; up to18 VA
Use a Class 1 ( properly fused ) or Class 2, CSA or UL recognized
transformer for power supply & relay outputs.
Agency Approval: cULus File # E212649
Specifications and equipment are subject to change without prior notice.
OVERRIDE TEST BUTTON
The override test button can be used to by-pass the interstage delay and
bring on all stage at one time. This simplifies the verification of configured
maximum number of stage. A status led per step will come on for each of
the configured stage.
INPUT SIGNAL
The R851B has four INPUT dip switch (S1 to S4) to select the control signal input: They are compatible with industry standard signals.
DIP SWITCH ADJUSTMENTS & WIRING CONTROL INPUT
Input Signal Switch
Switch #1
Switch #2
Switch #3
Switch #4
0 to 10 Vdc control signal ( 2 to 10 Vdc control range )
Off
Off
Off
On
4 to 20 mA control signal
Off
Off
On
Off
If a slave unit is used, wire the control signal input to the master unit only

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24 VAC POWER & RELAY OUTPUT WIRING
The wiring diagrams are for the R851B-8 models with 8 outputs. The wiring for the R851B-4 is the same except that the unit only
has 4 outputs.
Terminals
Screw terminal & connector #1 Common
Screw terminal & connector #2 24 Vac
Screw terminal & connector #3 Control Signal input
•It is not necessary to ground any leg of the transformer to earth with the controller card.
•The controller uses internally a half wave rectifier bridge. On 0 to 10 Vdc control signal, the reference of the control signal is the
Common of the power supply of the SCR controller card.
•Use a Class 1 ( properly fused ) or Class 2, CSA or UL recognized transformer.
ON
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16 STAGE APPLICATION (R851B-8 MASTER UNIT, R851B-8 SLAVE UNIT) (See also slave application section at the end)
The intensity of the yellow status LED on the master unit is proportional to the slave output.

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R851B DIMENSIONS & INSTALLATION
ON ON
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Install on the mounting plate on the electrical cabinet using five #6 pan head metal screw. Do not over torque the screws to prevent
damage to the board. Specifications and equipment are subject to change without prior notice.
All R851B series controls are for use only as operating controls. Whenever a control failure could lead to personal
injury and/or loss of property, it becomes the responsibility of the user to add safety devices and/or alarm system
to protect against such catastrophic failures.
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LINEAR / PROGRESSIVE
The R851B series features 2 different staging sequences:
•LINEAR 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
•PROGRESSIVE 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 R851B 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.
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%.
ADJUSTMENTS
Functions of the units can be configured with six dip switch and 2 potentiometers.
0 to 9 min.
0 to 60 sec.
Step up interstage delay potentiometers setting
 2 potentiometers are used to adjust the interstage delay from 0 seconds up to10 minutes.
 The value selected by both potentiometers will add up for the total step up interstage delay.
 This delay is the minimum time delay between each step activation when the control signal rises
Control
switch S2
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Step down & minimum ON time setting ( Control switch S2 )
Control switch S2 Off = 2 seconds On = 5 seconds
 This delay acts as a minimum ON time when each step is activated

The delay is also the step down interstage delay when the control signal drops

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VERNIER STAGE WIRING
SLAVE APPLICATION SECTION
When using a unit for slave applications, it is important that the proper adjustments & setting be made to the unit for proper
operation of the system.
The yellow LED near the vernier output connector is proportional to the vernier output of the master unit ( 0 to 5 Vdc ).
On the slave unit:
•Set vernier ratio potentiometer to 100%
•Set interstage delay potentiometers & S2 switch to the same value as the master unit
•Set all control signal INPUT dip switch on the slave unit to OFF
TEST MODE BUTTON
The test mode button can be used to verify if the number of stage have been configured properly.
1. Press and hold the button for 3 to 4 seconds.
2. If a slave unit is used, press & hold the 2 units button simultaneously
3. All the selected stage will come on, one after the other until all selected number of stage are all on.
4. There is a delay of approximately 5 second between each step activation.
5. When all selected stage are on, they will stay on for approximately 30 seconds before shutting down.
Powering up the R851B controller while holding down the test button will by-pass the interstage delay for 10 minutes. During that
period, the unit will respond to a changing signal input very rapidly. Also hold down slave test button on start-up if a slave unit is used.
After that 10 minute period, the unit will function normally with the interstage delays active
CALIFORNIA PROPOSITION 65
WARNING
CALIFORNIA PROPOSITION 65
This product can expose you to chemicals including Lead, which are known to the State of California to cause cancer and birth
defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov.
Failure to follow these instructions can result in birth defects or other reproductive harm.
Viconics Technologies Inc.
7262 Marconi | Montreal | Quebec | Canada | H2R 2Z5
Tel.: [phone] | Toll free: 1 800.563.5660
[e-mail] | www.viconics.com
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R820
SCR Power Controller
The intensity of the green status LED on the master unit is proportional to vernier output
0 to 10 Vdc analog output to activate R820 SCR power controller
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