What is the function off the “ISC start delay”, when does it work?

What is the function off the “ISC start delay”, when does it work?

ISC start delay (P81.02)


Q: What is the function off the “ISC start delay”, when does it work?

A: It is a sequential start function, this feature is intended to prevent that all compressors or motors will start at the same time during a system start.

The “ISC start delay” will ensure an interval time between the start/delta cycle of each compressor.


The ISC start delay will only work during a system start or when a compressor has to change from not running to running. This is because the star/delta cycle of a motor requires a lot of energy.

The ISC start delay will not work when a compressor is going offload and to needs to go back to load whilst still running. This is because the motor is still moving and does not have to go through a star/delta cycle.

    • Related Articles

    • ISC function set-up instruction

      The purpose of the ISC function is to establish pressure system control in preference to using the local pressure control on all individual compressors. Once installed, the host / master air compressors Airmaster™ ISC software feature will then save ...
    • How to set-up a remote start/stop configuration on the Q1 controller?

      Remote start/stop via digital inputs        A digital input will be used to implement the start/stop function. The function of digital inputs 2 to 7 are adjustable. In the below example DI2 is used. In the P18.02 menu, set the function of DI 2 to ...
    • I have changed the ISC rotation interval (P80.04) but the controller doesn't seem to apply the new setting.

      ISC Sequencing - Rotation Interval Q : I have changed the ISC rotation interval time (P80.04) but the controller doesn’t seem to apply the new setting (e.g. changed to 50 hrs but the sequence rotation happened after less than 24 hours). A : Please ...
    • Additional information for parameter "Run Check Delay"

      P12.33 Run check delay One of the selectable functions for a digital input is checking a feedback signal of a motor relay. P12.33 determines the time the DI has to change status.
    • How to set up Q1 for ISC (Master/Slave)

      This document describes how to connect and configure 2 Q1 controllers for Master/Slave control (ISC). Also available for download are the commissioning forms for Q1 Master & Q1 Slave. These commissioning forms describe which parameters need to be ...