October 13, 2009 Mark Kozlovsky1 Final Production Revision DECam Heater Controller System

October 13, 2009 Mark Kozlovsky2 Final Production Revision 1.HEATER DRIVER BOARD a)Control signals for overheating LEDs were reversed so LEDs were ON all the time. Correction Action: inverters are added in front of opto- couplers. b)LED power switch which allows for disconnecting LEDs during normal operation had wrong footprint and could not be installed. Correction Action: library part and footprint for the switch were corrected. c)A screw that holds telemetry connector was very close to +15V_Heater via and sometimes top layer will wear away causing a short. Correction Action: PCB layout is changed to prevent the occurance. d)Shutdown signals for hot swap controllers were impossible to use and monitor because of crate construction limitations. Correction Action: Signals were brought from transition boards to the Heater Driver Boards to be transferred through additional isolation buffers to the telemetry connectors and further to a Slow Control Subsystem

October 13, 2009 Mark Kozlovsky3 Final Production Revision PinConnection 1Input Test1 2Out Test 1+ 3Out Test 1- 4Input Test 2 5Out Test 2+ 6Out Test 2- 7GND_Control 8 9Overheat 1+ 10Overheat 1- 11Overheat 2+ 12Overheat 2- 13nShutDown 14Aux_Test 15GND_Control Telemetry Connector

October 13, 2009 Mark Kozlovsky4 Final Production Revision 2.HEATER DRIVER BOARD TRANSITION BOARD a)Value of the resistor R42 was a little bit too small to drive nShutdown signal to log “0” (< 0.8V). Correction Action: Value of Resistor R42 is changed from 3.74K to 4.32K b)The Hot Swap Controller will sometimes shut itself down because of the inrush current on its negative supply. The setting for the controller shutdown is 4.17A. Correction Action: Value of capacitor BP1 is changed from 0.01uF to 0.047uF in order to limit slew rate for the negative output. c)Input connector Adam Tech Fully Shielded Mini DIN 8-position Jack had wrong footprint and could not be installed. Correction Action: library part and footprint for the connector were corrected. d)nShutdown signal was not connected to the Slow Controller Board due to crate construction limitations. Correction Action: nShutdown signal is connected to +5V on J9 in order to be monitored as regular power supply via Analog Power Backplane.

October 13, 2009 Mark Kozlovsky5 Final Production Revision 3.HEATER PATCH PANEL BOARD a)The front panel has to be machined around Control input and Heater output connectors to allow plug-in cables to be fully connected. Correction Action: Front panel drawing is changed accordingly b)The Control input connector has wrong pin assignments on the main schematic. Correction Action: Pin assignments are change according to the Table 1.

October 13, 2009 Mark Kozlovsky6 Final Production Revision Pin Number Incorrect Signal Name Correct Signal Name A2Control_input_12Control_input_2 A3Control_input_11Control_input_1 A5Control_input_8Control_input_3 A6Control_input_7Control_input_4 A8Control_input_4Control_input_5 A9Control_input_3Control_input_6 A11Control_input_2Control_input_7 A12Control_input_1Control_input_8 A16Control_input_10Control_input_9 A17Control_input_9Control_input_10 A19Control_input_6Control_input_11 A20Control_input_5Control_input_12 Table 1.

October 13, 2009 Mark Kozlovsky7 Filter Frequency Response 4.HEATER PATCH PANEL TRANSITION BOARD a)Input connector Adam Tech Fully Shielded Mini DIN 8-position Jack, had wrong footprint. Correction Action: library part and footprint for the connector were corrected.