Revision 1.1
Variphase User Manual
Page 9
Control Mode Overview
Variphase operates in one of five selectable modes:
1. Networked Speed Control
2. Analog Speed Control
3. Networked Control with Tachometer Speed Regulation
4. Analog Control with Tachometer Speed Regulation
5. Analog Closed Loop Control
Speed regulation modes use an external Hall-effect sensor to provide a speed feedback signal
from the motor. In this mode, Variphase will hold motor speed constant, even under varying load
conditions. In networked mode it also allows the speed to be set in RPM units.
Modes are selected using Jumper Shunts JP1 and JP5, and by network commands from AirCare
Consoles.
In Analog Closed Loop Control Mode, Variphase compares an Analog feedback signal to an Analog
set-point and adjusts speed accordingly.
All Closed Loop control modes (Modes 3-5) use a fully programmable PID loop to allow response
and stability adjustments.
An AirCare networked system requires a compatible Modbus host. In most cases this will be an
AirCare Automation Console, but other Modbus devices can be used if configured correctly. Refer
to the Network Specification section of this document for more information.
Option Jumpers
JP1
JP2
JP3
JP4
JP5
JP6
Analog
20mA
Baud
4-20mA
Regulate
Speed
4-Wire
Table 2
Analog
Install jumper to select analog input speed control from either 0-5V or
4-20mA sources. When jumper position is open, the control responds
to Modbus speed commands.
20mA
Install Jumper to enable current loop shunt on Analog Input 1. JP1
should also be closed to enable 4-20mA control. Leave switch open
for 0-5V control.
Baud
Install jumper to select 9600 baud. Default is 1200.
4-20
Install jumper to enable 4-20mA loop on Analog Input 1. If jumper
position is open, the 4mA offset will not be factored, resulting in a 0-
20mA control range.
Regulate
Speed
Install jumper to enable closed loop control using an external speed
sensor. The sensor will be used to regulate the set speed in RPM. If
jumper position is open, the sensor input will not be used for motor
speed control but in network control mode, RPM will still be reported if
a sensor is connected.
4-Wire
Fit Jumper to select 4-wire (RS422) communications. Default (jumper
open) is 2-wire (RS485) communications.
