CCD Cold Head Temperature Controllers

Table of Contents:

Introduction

Instec (https://instec.com/) thermal controllers and liquid nitrogen (LN2) pumps are used as part of the KPF CCD thermal control system (see CCD Thermal Control System).

A thermal sensor within the cold head is monitored by the mK2000B controller, which then calls for more cooling (by increasing the speed of the pump to draw more LN2 through the system), or for more heating (by increasing the power going to the heater element within the cold head). Cooling or heating needs are determined by comparison against the desired temperature set-point, and the response of the system is tuned via PID control parameters.

The mK2000B controller and LN2-SYS pump are standard Instec products. The cold head was custom-designed by Instec for the KPF system.

Relevant Devices

Description	Qty	Source	Part Number
Cold Head Temperature Controllers (Green and Red)	2	Instec	mK2000B
LN2 Pumps (Green and Red)	2	Instec	LN2-SYS
Cold Heads (Green and Red)	2	Instec	Custom for KPF

Relevant Functional Block Diagram

Also see CCD Thermal Control System for more details on the entire thermal control system (including LN2 connections).

The vacuum feethru is described as: “INSTRUMENTATION FEEDTHROUGH, DOUBLE ENDED SUBMINIATURE-D STYLE CONNECTOR, GROUNDED SHIELD, RECESSED CONDUCTOR(S), 15 PIN, 500V AND 5 AMP RATING PER PIN, MOUNTED ON A DN40CF (2.75" OD) FLANGE.” It was purchased from Lesker (PN IFDGG151053). More details on the feedthru in the 'Relevant Datasheets and Manuals” section below.

Cable Details

Cable	Qty	Details	Notes
Ethernet	2	Cat6 Copper Ethernet Cable M-M, 6 feet long	Entirely within Aux Rack. One for Green, one for Red.
Mains power cables - mK200B	2	NEMA 5-15P to C1314 AWG Power Cord	Entirely within Aux Rack. One for Green, one for Red.
Mains power cables - Pump	2	See Aux Rack External Cables	One for Green, one for Red.
Instec Pump Cable	2	See Aux Rack External Cables	One for Green, one for Red.
Instec Sensor and Heater Cable (Air and Vacuum Sections)		Air-side Instec cable: Vacuum-side Instec cable (and Cold Head, with LN2 connections):	Air section is a custom 30-ft long DB15 M-F cable made by Instec (our quote # was 2011632). This cable goes between the Instec controller and the vacuum feedthru on the main vacuum chamber. Within the chamber there is a second vacuum-compatible cable between the vacuum feedthru and the Instec Cold Head. This cable is not a separate item; it is hard-wired into the Cold Head and is not removable.

Relevant Datasheets & Manuals

	Description	Source
1	mK2000B User Manual	email from Instec
2	mK2000B Command Reference	email from Instec
3	LN2-SYS Pump Manual	email from Instec
4	Vacuum Feedthru	https://www.lesker.com/part/part.cfm?partnumber=ifdgg151053&op3partsection=feedthroughs/instrument-feedthroughs-mpdt-subd

Relevant Software (from Development Phase)

	Description	File	Source
1	Instec said: “While we do have sample code for Python, it is based on a USB connection, not Ethernet. Our documentation on Ethernet programming is limited because it isn’t very frequently used for custom applications. This ZIP file contains example code for python using a USB connection. It could serve as the basis for an ethernet version.”		email from Instec
2	Ethernet communication setup from Instec. Mainly describes how to write code to find Instec devices on a network. Note PacketSender image within, which shows correct port to use for ethernet communication.		email from Instec
3	PacketSender connection example		Screengrab of SG’s successful connection to device through PacketSender. Note port is 50292.
4	Instec App for Windows (standalone program; not useful for KTL but included here for completeness)		email from Instec
5	Steve’s python code that uploads a PID table from a .csv file (in Instec format) to the device over USB. Example PID tables also included (one with actual values, and one with integers that was useful for testing code).	Code: PID files:	Steve’s test of parsing and uploading Instec .csv file
6	Calibration table decoder ring (output of CAL:TAB command)	The data is formatted as follows: The return data is 171 bytes long. The first byte is “#”, while the last two bytes are the “return” (0x0D) and “New line” (0x0A) characters. The 6^th byte describes the data type; 0 = TM, 1 = Calibration Table C1, 4 = Calibration Table C4 etc… The 7^th byte is the number of entries in the calibration table. The actual calibration data begins at the 10^th byte. For each in the calibration table, there are two floating point numbers which correspond to T0 and Ts. Each floating point number consists of 4 bytes, which are arranged in little endian order.	email from Instec
7	Controller calibration file example. Filename structure is: “cold_head_SN & mK2000B_SN cal.clb”

KTL Dispatcher Configuration File

Configuration	Value	Explanation
dispnum	1	Dispatcher number
address	192.168.23.145	IP address of the Instec
port	50292	Port number of the Instec
model	MK2000B	model of the Instec, used to find the serial number
poll_time	10	how often in seconds the various values are queried
calfile	@RELDIR@/data/@KTLSERVICE@/KCPE2006054_KSE48Sm22001147_cal.clb	calibration file for the controller, on connection the table is read in and then compared with the values in the Instec controller