Solar Calibrator (SoCal) Electronics

Table of Contents:

1 Introduction
2 Relevant Devices
3 Relevant Functional Block Diagram
4 Cable Details
5 Relevant Datasheets & Manuals
6 Relevant Software

Introduction

The Solar Calibrator (SoCal) is mounted on the WMKO roof and is comprised of two main components: a sun tracker with mounted optics and a weatherproof enclosure. A 90-m run of four (sci, cal, spare, HISPEC) optical fibers delivers disc-integrated sunlight to the WMKO basement. The Sci fiber illuminates KPF Sci/Sky fibers via its own stage on the cal bench, while the Cal fiber is connected to the octagon and may be selected just like any other calibration source.

Relevant Devices

System	Description	Qty	Source	Part Number

System	Description	Qty	Source	Part Number
Network	Industrial network switch	1	Planet Tech	IGS-801M
Sun Tracker	Alt/Az two-arm sun tracker	1	EKO Instruments	STR-22G
Sun Tracker	RS232/TCP network gateway	1	Lantronix	UDS2100
Irradiance	Pyrheliometer	1	EKO Instruments	MS-57
Irradiance	Modbus Signal Converter	1	EKO Instruments	MC-20
Irradiance	Modbus/TCP network gateway	1	Lantronix	UDS1100-IAP
Enclosure	Custom clamshell-style dome and DomeGuard computer	1	FORNAX	Raspberry Pi
Power	24 V power supply	1	Mean Well	NDR-240-24
Power	12 V power supply	1	Mean Well	EDR-120-12
Power	24 V UPS	1	Mean Well	DR-UPS40

Relevant Functional Block Diagram

SoCal electronics box with annotations. Not shown is the ethernet connection from the KPF main switch plugged in to the SoCal switch (IGS801M).

Block-diagram schematic of the SoCal electronics

Cable Details

Cable	Qty	Details	Notes

Cable	Qty	Details	Notes
RS232 (DB9)	1	Connects Sun Tracker to UDS2100 for serial communication. 3 m cable length (SC-22-C3). EKO also makes a 5 m (-C5) and 10 m (-C10) version.	About $200, 1 month lead time if we want a spare/replacement.
RS485 2-wire (DB25)	1	Connects the comms wires from the Pyrheliometer, after coming from the MC20 modbus converter, to a DB25 plugged into the UDS1100-IAP.	See Figure 12-4 on page 70 of the UDS1100-IAP User Guide (above) for the pinout used in RS485 2-wire mode.
Various ethernet cables (RJ45)

Relevant Datasheets & Manuals

	Description	File	Source

	Description	File	Source
1	EKO Sun Tracker Command List		EKO Instruments
2	STR-22G Manual		EKO Instruments
3	MC-57 Pyrheliometer Manual		EKO Instruments
4	MC-20 Modbus Manual		EKO Instruments
5	DomeGuard Manual		FORNAX
6	Motor driver replacement guide (useful images of DomeGuard electronics)		FORNAX (Gábor Kovács, alexis077@gmail.com)
7	Lantronix UDS2100 User Manual		Lantronix
8	Lantronix UDS11000-IAP User Manual		Lantronix
9	Lantronix UDS1100-IAP Modbus protocol user guide		Lantronix