Tube Heaters Hook-Up
What follows is a short description of how to hook-up the tube heaters on the Horizontal Gas Flow I, Horizontal Gas Flow II and Ms. Piggy Cryostats. There are actually 4x100 Ohm heaters along the length of the cryostat tube. Each two are connected in parallel so one has a 50 Ohm heater at the warm end of the cryostat and a 50 Ohm heater at the cold end.
Use the cables provided, the 10 socket M connector should be attached to the type M 10 pin connector on the cryostat with a white Aluminum cap thermometers and heaters connectors. The other end should be connected as labeled on the cables to the 2 pin Lemo connectors on the power supplies electronic rack in each experimental area.
In case of trouble the following pin out is used:
Line 1: LK Cold Heater
Line 2: AH Warm Heater
Line 3: CB Warm Platinum
Line 4: FJ Not Connected
Line 5: DE Cold Platinum
A LakeShore 218 temperature monitor is used to read the two platinum sensors placed on top of the heaters. When the temperature reaches a preset value around room temperature the power to the heaters is turned off. If the temperature then drops by more than few degrees the heater will come back on. To achieve this on/off temperature control we use the relays and alarm capability of the lakeshore 218 temperature monitor.
The relays on the rear panel of the 218 monitor should be wired as shown below. Relays 3 and 4 provide the extra protection in case the temperature monitor is turned off.
Pin Description
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Heater 1 (Red) 1 Relay 1 NC (Normally Connected)
** 2 Com Relay tied to alarm operation
* 3 NO (Normally Open)
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Heater 2 (Green) * 4 Relay 2 NC
* 5 ** Com Relay tied to alarm operation
* 6 * NO
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* 7 * Relay 3 NC Relay set to the active state
** 8 * Com Trips power if Lakeshore is
Heater 1 (Orange) 9 * NO turned OFF
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10 * Relay 4 NC Relay set to the active state
11 ** Com Trips power if Lakeshore is
Heater 2 (Blue) 12 NO turned OFF
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13 Analog Sig
14 Analog Gnd
To setup the alarms follow the steps below. For more details refer to the lakeshore 218 manual.
Alarm setup ! Press alarm setup
Input 1 ! Select input 1 with the data selection keys press enter
Alarm on ! Enable alarm operation for input 1
Unit K ! Set the units to K
Low alarm point 30 K ! Trips power if the Platinum sensor is unplugged
High alarm point 300 K ! Trips power to the heaters at 300 K
Deadband 5 K ! Heaters will come on if temperature drops below 295 K
Latching off ! Heat will come back on if the temperature drops by 5 K
Audible alarm off
The relays should be configured as follow:
Relay Setup ! Press relay setup
Relay 1 ! Select relay 1
Mode_alarms ! Relay will be tied to alarm operation
Input 1 ! Select the sensor to which the relay applies
Both alarms ! Relay active when high or low alarm is active
Relay 3 ! Select relay 3
Mode_on ! Replay manually set to active state
! Trips power if Lakeshore is turned off
Finally, the same procedure has to be followed for input 2, relay 2 and replay 4.
