APC-SV4 and APC-SV8 Step Control Users Manual
Low Voltage Step Control with Vernier Stage (ver 1.02)


1 Ordering Code
APC-SV8 - Eight Position Step Control with Vernier
APC-SV4 - Four Position Step Control with Vernier

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 2 Description
The APC-SV8 is a microcontroller-based step controller that provides precise modulation in multi-stage heater applications such as duct heaters. The built-in Vernier stage allows for smooth, precision control of the load without increasing switching wear.

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3 Key Features
  • Adjustable Stage Delay
  • Pulsed or Analog Vernier Output
  • Adjustable Vernier Ratio
  • Expandable to 16 stages
  • LIFO/FIFO Selection
  • Test Button
  • Brown Out Protection

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4 Installation
WARNING: FIRE HAZARD!!  Even quality electronic components CAN FAIL KEEPING FULL POWER ON!  Provide a SEPARATE (redundant) OVER TEMPERATURE SHUTDOWN DEVICE to switch the power off if safe temperatures are exceeded.
WARNING: HIGH VOLTAGE!!  This control is wired to a transformer, Solid State Relay, and contactors with high voltage on them. This control must be installed in a GROUNDED enclosure by a qualified electrician in accordance with applicable local and national codes including NEC and other applicable codes. Provide a safety interlock on the door to remove power before gaining access to the device.
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4.1 Mounting Instructions/Dimensions

The APC-SV8 should be mounted using #6 screws at the five locations shown below. The board is supported by 5, 5/16" high spacers (supplied).

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5 Dipswitch Settings


5.1 Input Selection
S1 positions 1-5, select which command input the APC-SV8 will accept.

0

Switch S1

0

Pos 1

Pos 2

Pos 3

Pos 4

Pos 5

Command Input

mA

mA

10V

135R

135R

0-5V

OFF

OFF

OFF

OFF

OFF

0-10V*

OFF

OFF

ON

OFF

OFF

2-10V*

OFF

ON

ON

OFF

OFF

4-20mA

ON

ON

OFF

OFF

OFF

0-135 OHM

OFF

OFF

OFF

ON

ON

*If the 0-10V range is selected, the APC-SV8 will start responding with output just above 0V on the command input. If the 2-10V range is selected, the APC-SV8 will start responding with output just above 2V on the command input.

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5.2 Stage Selection

S2 positions 1-4 select the number of output stages.

0

Switch S2

0

Pos 1

Pos 2

Pos 3

Pos 4

Output Stages

STP3

STP2

STP1

STP0

1

OFF

OFF

OFF

OFF

2

OFF

OFF

OFF

ON

3

OFF

OFF

ON

OFF

4

OFF

OFF

ON

ON

5

OFF

ON

OFF

OFF

6

OFF

ON

OFF

ON

7

OFF

ON

ON

OFF

8

OFF

ON

ON

ON

9

ON

OFF

OFF

OFF

10

ON

OFF

OFF

ON

11

ON

OFF

ON

OFF

12

ON

OFF

ON

ON

13

ON

ON

OFF

OFF

14

ON

ON

OFF

ON

15

ON

ON

ON

OFF

16

ON

ON

ON

ON

 

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5.3 Output Mode Selection

LIFO (last in first out) and FIFO (first in first out) modes are both available by setting of S2 position 6.  

0

Switch S2

0

Pos 6

LIFO/FIFO

FIFO

LIFO

OFF

FIFO

ON

LIFO mode is the normal default mode. In this mode the output stages respond like a level bar graph.

FIFO mode circulates the on stages to promote even use of the contactors and elements. For example, the first stage that was turned on when the power was increasing will be the first stage turned off when the power is decreasing.

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5.4 Master/Slave Selection

S2 positions 5 selects master or slave operation.

0

Switch S2

0

Pos 5

Master/Slave

SLV

Master

OFF

Slave

ON

When the APC-SV8 is set for slave operation, the command input becomes the slave input. The slave's command input is wired to the master's slave output.

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5.5 Analog/Time Proportioning Vernier Selection

S1 position 6 selects Analog or Time Proportioning Vernier Output.

0

Switch S1

0

Pos 6

Analog/Time Proportioning

ANLG

Time Proportioning

OFF

Analog

ON

When Time Proportioning is selected, the Vernier output is a 24VDC current limited 4 second cycle time PWM signal. The SSR used to control the Vernier heater is driven from terminals TP+ and TP-.

When Analog is selected, the Vernier output is a 0-5V analog signal for driving a phase angle controller. The 0-5V signal is present on the AN+ and GND terminals.

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6 Adjustment Potentiometers

6.1 Stage Delay Adjustment
The Stage Delay is the time that it takes for additional stages to turn on or off. The Stage Delay is adjustable from 0-180 seconds (0-3 minutes). The stage delay must be set above zero or excessive contact wear can occur.

If the unit is to be used as a slave, then the stage delay should be set to 0 on the slave because the master's setting of stage delay will control it.

The Test Button will turn on each stage one at a time while pressed and will turn off the stages at the stage delay rate when let go.

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6.2 Vernier Ratio

The Vernier Ratio is the ratio of vernier heater to the heaters used on the individual stages. The Vernier Ratio is adjustable from 100 - 200%.

  • If the Vernier heater is the same power as the individual stage heaters, then the Vernier Ratio should be set to 100%.
  • If the Vernier heater is twice the power of the individual stage heaters, then the Vernier Ratio should be set to 200%.

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7 Test Button

When the test button is held down, the command input is forced to 100% and all of the stages will come on one at a time. When the button is let go, the stages will turn off at the set stage delay.

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8 Indicator LEDs

Power LED - On when power is applied.

Individual Stage LEDs - On as each stage is turned on.

Vernier Output LED - Increases in intensity when power is increasing and analog is selected. When Time Proportion is selected, turns on when the output is energized.

Slave Output LED - Increases in intensity when power is increasing to the slave input.

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8.1 Vernier Output - Master/Salve Configuration
In a Master-Slave Configuration, the master unit's Vernier output should always be used for driving the SSR or Phase control.

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8.2 Vernier Output - Time Proportioned Drive Specifications

When Time Proportioning is selected, the Vernier output is a 24VDC current limited 4 second cycle time PWM signal. The SSR used to control the Vernier heater is driven from terminals TP+ and TP-. The drive specifications are power supply related and are shown below.

SSR DRIVE CURRENT vs SSR VOLTAGE DROP AND POWER SUPPLY

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9 Electrical Specifications
Power Inputs
24VAC -15/+10%50/60Hz <4VA.
(24VAC -5%/+10% when using 0-135Ohm input)
Brown Out Protection
Stages restart from zero upon loss of power.
Command Inputs
0-5V, 0-10V, 4-20mA, 0-135R. Selectable via Dipswitch.
Stages
Selectable from 1 to 16 stages via dipswitch. More than 8 stages requires an additional unit setup for slave operation.
Stage Outputs

30 VAC @ 1.0A SPST Mechanical Relays w/MOV protection, up to a max of 5A total for all of the stages. Up to 8 stages per board.

Vernier Output
Current limited 24VDC Time Proportioned SSR drive or 0-5V Analog output for driving APCSCR control. Selectable via dipswitch # S1-6.
Slave Output
0-5V output for expanding beyond 8 stages.
Slave Output Modes
LIFO or FIFO Selectable via Dipswitch.
Stage Delay
Adjustable from 0-180 seconds via potentiometer.
Vernier Ratio
Adjustable via potentiometer from 100 to 200%.
Stage Output Indication

Each Stage has a Red LED that is energized when the normally open relay output is closed.

Vernier Output Indication
Green LED that varies in intensity when analog mode is selected or blinks when time proportioning is selected.
Slave Output Indication
Yellow LED that varies in intensity when a slave output signal is present.
Test Button
Forces the command signal to 100% while pressed, thereby allowing test of all the stages at the selected stage delay rate.
I/O Connectors
0.250" Faston Lugs for power and stage outputs, screw terminal blocks for low voltage I/O and command.
Ambient Temp. Range 0 to 80° C.
Board Specifications 7.075" x 2.700", RoHS compliant.
Shipping Weight Approximately 1 lb.
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10 Wiring Diagrams

10.1 Standard 8 Stage Wiring

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10.2 16 Stage Wiring Using Slave Board

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10.3 8 Stage Wiring - Time Proportioned Vernier for SSR Drive

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10.4 8 Stage Wiring - APCSCR Power Control Control on Vernier

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11 Contact Information
Anacon Power & Controls 
800-466-9080 
www.anaconpower.com

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©Copyright 2009 Anacon Electronic Sales, Inc.