PLC Controller How-To Guide for Smart Advance 1

Understanding, setting and adjusting the set point of your rental HVAC equipment PLC controller is easy. We’ve put together this handy guide you can keep as a reference for adjusting the set point of your Smart Cooling model SACP chiller rental so you can quickly read and modify your AC set-point as needed.

Common PLC Operation

The following are the common displays and adjustments related to your SA66 PLC controller:

  1. Viewing and Changing Set Point

 During normal operation, the current temperature is displayed on your PLC controller. You can check the set point and adjust it:

 Hold SET button for approximately 1 second to view current set point, a flashing number

  • Press UP or DOWN arrows to increase or decrease your AC set-point
  • Press SET again to store new value
  1. Understanding Blinking Output Icon

 There are four OUTPUT icons along the left side of your display. They indicate the state of your outputs. If one or more of these icons are blinking:

 Your controller is calling for an output activation

  • A delay is keeping this activation off for a fixed period of time, i.e., minimum “OFF” time for your chiller as a compressor cycling precaution
  • The  light number indicates the numbered output on the wiring diagram
  1. Common Alarms

 Alarms will display on your screen, alternating with the temperature reading. Some of the most common errors that need your attention include:

  • EO1 = Probe 1 error
  • E02 = Probe 2 error
  • E04 = High temperature alarm
  • E05 = Low temperature alarm
  1. Accessing Parameters

 You have access to a certain number of parameters through your SA66 HVAC equipment PLC controller to adjust your chiller operation. To access these parameters:

  • Hold down both SET and PRG for 5 seconds until you see “0”
  • Hold the UP arrow until you get to 77
  • Press SET to enter the parameter list
  • Press UP and DOWN to toggle through the parameters list
  • Press SET to enter/exit the parameter field
  • Press UP or DOWN to adjust the value of the parameter
  • Hold PRG for 5 seconds to save your changes

Some of the most common parameters you can adjust on your rental HVAC equipment include:

  • c0 = operating mode. If value = 1, all outputs stage up and down proportionally as cooling outputs. If value = 2, all outputs stage up and down proportionally as heating outputs
  • c18 = temperature unit of measure, where 0 = Celsius, 1 = Fahrenheit
  • St1 = controller set-point, or cut-out temperature
  • P1 = differential for St1 (cut-in temperature for each set point — this value is added to St1 for cooling, subtracted from St1 for heating)

Note, this differential is distributed evenly amongst all outputs during proportional staging. For example, if a 2-output SA66 model is programmed in cooling mode (c0=1) with St1 = 50 and P1 = 10, Output1 will come ON at 55 and OFF at 50. Output2 will come ON at 60 and OFF at 55. Above 60, both Outputs will be ON.

  1. Important Note

While you can easily access many set points and parameters of your rental HVAC equipment through the PLC control panel, changing the set points MAY void the equipment warranty. Please verify any changes with an approved service agent.

If you have any questions about the PLC control of your Smart Cooling rental chiller after reading this guide, feel free to contact our team here at Smart Family. We’ll explain the various controls and set points and help you set your controller for optimal performance of your rental cooling equipment.