IEP® CRAC Controller


With the CRAC Controller (CRAC = Computer Room Air Conditioner) for Chilled Water (CW) systems developed by us, the user has a manufacturer-independent control system for the individual data center.


The IEP® CRAC Controller consists of the following components:


  • Display (5.7-inch display with touch screen, display up to 19-inch available)
  • Ethercat Bus Coupler (0V-10V interface card (2 ports), PT100 interface card (2 ports), RS485/Modbus RTU card (up to 115.2 kBaud), EtherCAT Bridge card as interface to the IEP Master System)


The controller has two simple control settings: in Local Mode, the control of the recirculating cooling units is carried out autonomously by the Control Panel, but the Local Mode can be set variably. There are five different modes available to you.


The second option is the IEP® control mode: the setpoint data for the fan speed and the valve are provided by the IEP® Master System.


The CRAC Controler offers the following features:

  • Monitoring via EtherCAT interface (Heart-Beat function): If there is no heart beat, the display switches to fail-safe mode. Values for recirculation cooling can be set via touch panel
  • Separate 24V DC power supply with wide range input (110V to 240V AC)
  • RS485 serial interface for Modbus RT provides data to the building management system
  • EtherCAT Bridge Clip for connection to the superior IEP® EtherCAT system
  • Differential pressure 0PA...50PA
  • Output relay clip for controlling the 3-way valves in the recirculation cooling unit
  • The CRAC controller is password-protected and consequently ensures even more security
  • An USB flash drive is used for configuration purposes


The CRAC Controller System replaces the manufacturer-specific onboard CRAC controllers with extended functionality regarding energy efficiency and ergonomics in the handling of the system:

Due to the 5.7" display, a simple user-guided menu structure (patented tile surface) is realized, which not only provides the local data of the ULK system, but also displays all room data of the entire data-hall via the EL6692, in which the ULK is installed.

A CRAC display controller from CPI with its error-free technology monitors up to 30 CRAC units and 30 cold aisles. Error-free means that the system automatically switches to default mode in case of a failure.

As an alternative to the examples above, the following interfaces can be provided:


  • Modbus TCP
  • BACnet
  • Profibus (Slave)
  • further ports on request


Optionally, a humidifier unit with a 0V-10V port is available for humidifying the data center. The actual values in % (relative humidity) are transmitted to the control of the CRAC controller and then processed, via a humidity sensor.


The IEP® CRAC Controller has two control methods: Control of cold aisles with an energy saving of up to 90% or without cold aisles a regulation of the floor pressure with an energy saving of up to 60%.

The CRAC controller can be easily integrated into existing data centers. The following table provides an overview of energy savings of up to 90%:


1.     Order your new CRAC controller with EtherCAT Fast Connect Bus Coupler from any manufacturer (Stulz, Emerson, Hiref, etc.)

2.     Upgrade your system with the CRAC Controller, either from your service partner or through our worldwide dealer network

3.     Install the IEP® Controller in your data center and operate all CRAC units with the IEP® Controller and the innovative software

Result: The first stage to high energy savings has been achieved!

4.     Add your cooling units to the CRAC controller as soon as your IT becomes available

5.     Finally, install the EtherCAT Fast hot connect sensors (PT100/Ashrea (SLA)) for your cooling units.


Result:  The second and final stage for energy savings of up to 90% in your data center is achieved!

It is not necessary to program the controller: The unit is simply connected to the system, configuration is done via Internet.