APF Electronics Manual, EL-3517

APF Spectrograph Electronics

RIO-47102 Multistack Dome Chiller Monitor

Schematic: schematics\APF_multistack_monitor_sh_1.pdf
Page last updated: August 22, 2012

Sheet 1

APF_multistack_monitor_sh_1.pdf

Simplified Diagram

PURPOSE AND SCOPE:

The purpose of the Galil RIO-47102 is to monitor the error and status outputs available on the Airstack (Multistack) Chiller, which is used to chill the APF dome. The idea behind the dome’s cooling system is that by chilling the air inside the dome the difference between the telescope and the outside air can be minimized. The Multistack dome chiller is located outside of the APF dome and has four individual outputs that we are currently monitoring. We use the RIO-47102 for the error and status conditions. The RIO-47102 is located on the first floor of the dome on the back side of the electrical panels. The RIO-471xx series controller's digital inputs 0-15 are opto-isolated inputs with a range of 5-24VDC. The INC0 and INC1 can either be connected to the positive side of a DC power supply or to the Ground side of a DC power supply. We connect the ground signal of the Multistack Chiller to INC0 on the RIO. The error and status outputs available on the Airstack (Multistack) Chiller are all 24 Volt AC signals. In order to convert the multistack's 24 Volt AC signal to a useable DC signal for the RIO, the voltages must rectified to the appropriate levels as per the circuit shown on Sheet-2 of the schematic APF_multistack_monitor_sh_2.pdf. This circuitry lives inside the high density DB44P shell (See "High Density DB44P Shell" thumbnail on this page). The Alarm output, wired to the pump package portion of the chiller.

ERROR CODES FOR CONTROLLER DATA INPUTS:

The output labeled as “Alarm” is monitored on the RIO as Digital input “0” or “DI0” An active low indicates the Alarm has been triggered.

NO3 of the master control is simply an indicator that the compressor is running in its normal operational mode . NO3's output will be high in normal operation, a low indicates an error. This output is monitored on the RIO on Digital input “2” or “DI2”.

The FLR of the master Control indicates the compressor is in a full load condition. On some systems the FLR output is used to turn on a second compressor, if a second compressor is available. On the APF chiller and we simply use the FLR output to monitor the “full load” status of the pump and compressor. The output is labeled as “FLR” is monitored on the RIO as Digital input “5” or “DI5”. A High indicates the FLR condition has been triggered.

The last status output we monitor is the CAR output of the master control. This output indicates a FAULT CONDITION due to a loss of compression, flow, phase fault, low voltage or a temp sensor. The output is labeled as “CAR” and is monitored on the RIO as Digital input “6” or “DI6”. A High indicates CAR has been triggered.

RESETTING THE MASTER CONTROLLER FROM A FAULT CONDITION:

TO RESET A FAULT CODE IF TRIGGERED.

1). Press the alam button.

2). press the down arrow to view faults.

3). Press the enter button twice to clear fault.

4) Press enter again to start. You should see a countdown in seconds on the display until the system turns on.

NOTE: Resetting a fault code only works if you've repaired the unit, or the fault has passed. If the fault does not clear there is a failure somewhere in the system. You may be able to still start in manual mode, but the staging of the compressors is done by its module board. The control is independent of the other modules and is based on the LCHW (water temp) of that module. When in Auto Mode the staging of the compressors is handled by the master controller. There is a large toggle switch labeled "Manual - Off - Auto" near the uper right of the Master Control. It is advised to contact tech support at Multistack before you proceed in manual mode. The number for Multistack is 608-366-2400.

See "Faults" starting on page 13 of the Multistack / Airstack APF User Manual listed below for more information on Fault codes.

Sheet 2

APF_multistack_monitor_sh_2.pdf