8
Part 5
– Control
5.1
– Overview
The controller mounted on the DynaFLO is equipped with a
4.3” touch-screen display as well as built-in I/O, networking
and data-logging capability. The controller constantly
monitors the outlet temperature of the DHW (Domestic Hot
Water) side through an accurate 3 wire RTD. Based on the
feedback from the outlet RTD it then sends a signal to the
3-way electro-
hydraulic actuator that’s on the boiler side to
regulate the amount of heat coming through the heat
exchanger. The controller does this modulation on a
continuous basis based on a PID loop such that the outlet
temperature on the DHW side remains /-1°F of user-
selected set point in steady-state conditions. The PID
parameters that define the way the controller modulates are
protected by a factory level password. The default
parameters have been fine-tuned after extensive testing
and it is recommended not to change them. The image
below demonstrates the relationship between the controller
and other components:
For alarms, the controller also has a digital output (O1) that
is programmed to turn ON and stay ON once there is a new
alarm, this output could be used for remote operations. The
controller also has another digital output (O0) that starts
switching ON and OFF once there is a new alarm, this
output could be used with a flashing lamp. More details
about digital alarm outputs are explained in 5.2.2 and 5.2.3.
The Controller has a Modbus (RS-485) port for
communications. Port 2 (shown in the image below) allows
communication with a Modbus Master such as a BMS. A
Modbus Master can read and write the set point, get alarm
notifications and clear alarms, directly control the actuator
and etc. More information about the parameters that can be
accessed by a Modbus Master is given in section 5.2.1. The
Modbus Map table on the following page lists all the
parameters that can be accessed by a Modbus Master.
Port 2 is a RJ11 type connection, 6POS2C (A and B
signals).
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