TELEDYNE HASTINGS INSTRUMENTS INSTRUCTION MANUAL DIGITAL AVC (DAVC-4, DAVC-5, DAVC-6) ISO 9001 C E R T I F I E D
Manual Print History The print history shown below lists the printing dates of all revisions and addenda created for this manual. The revision level letter increases alphabetically as the manual undergoes subsequent updates. Addenda, which are released between revisions, contain important change information that the user should incorporate immediately into the manual. Addenda are numbered sequentially.
Table of Contents 1.0 GENERAL INFORMATION ............................................................................................................................ 4 1.1 FEATURES ....................................................................................................................................................... 4 1.2 SPECIFICATIONS ............................................................................................................................................. 4 1.
1.0 General Information This manual contains technical and general information relating to the installation, operation, and calibration of vacuum gauges and gauge tubes manufactured by Teledyne Hastings Instruments (THI). For best performance, THI vacuum gauges should be operated with the appropriate THI gauge tube. Attempting to use a THI vacuum gauge with another manufacturer’s tubes may result in damage to both the gauge and tube. 1.
1.3 Compliance data CE Standard Compliance Test Standard SAFETY EN61010 EMC/EMI Family EN61326 CONDUCTED/RADIATED EN55011 ESD EN61000-4-2 RF EN61000-4-3 CONDUCTED IMMUNITY EN61000-4-6 1.4 Safety The following symbols and terms may be found on THI products and/or in THI manuals and indicate important information. When found on the device, this symbol indicates that the operator should refer to the manual for important instructions on the proper use of this device.
1.4.3 Calibration Reference Tubes THI Reference Tubes employ the same metal thermopiles used in all THI Vacuum Gauge Tubes. The thermopile is sealed in a glass capsule that has been evacuated, baked, out-gassed, and then aged to ensure long-term stability. The sealed capsule is then housed in a protective metal shell to provide a rugged, trouble-free assembly. Once assembled, the reference gauge tube is accurately calibrated to precisely simulate a gauge tube at a given operating pressure.
2.0 Installation 2.1 Power-I/O Cable The Power-I/O Cable is assembled at the factory as shown in Fig. 1. Its terminal end is finished with stripped wire ends each tinned with lead free solder. This configuration is consistent with the previous, analog version of the AVC and its color coded wire assignment remains the same, as much as possible, considering the additional features of the Digital version. Fig 1 2.
ALARM 1 DIGITAL COMMON ALARM 2 +VDC POWER COMMON DIGITAL COMMON DIGITAL COMMON Fig.
3.0 Vacuum Gauge Operation All THI gauge tubes are shipped with a protective cap or cover at the evacuation port to reduce contamination and prevent damage to the internal thermopile elements. Once the protective cap or cover is removed, a tube can be installed in any convenient position in the vacuum system without adversely affecting calibration or performance. The recommended orientation is with the tube vertical and its stem down.
This signal is equal to an amplified tube millivolt signal. This signal will NOT be linearly proportional to the indicated pressure. 1 volt (1.2 for DAVC4-1.2V) will correspond to a system pressure that is at least 1 order of magnitude less than the minimum detectable pressure. Increasing pressure will be indicated by a decreasing voltage. The minimum detectable pressure is 0.2 millitorr for DAVC-5, 1 millitorr for DAVC-6 and 20 millitorr for DAVC-4.
Analog Output vs Pressure 100 DAVC6 DAVC4 DAVC4-1.2V 10 DAVC5 Pressure (Torr) 1 0.1 0.01 0.001 0.0001 0 174-082010_Digital AVC 0.2 0.4 0.6 Voltage 0.8 1 1.
3.3 Alarm Set point A single set point controls two open collector circuits. Though not the mechanical relays, the two circuits called Alarm 1 (P > SP) and Alarm 2 (P < SP) allow physical monitoring of the state of the vacuum with respect to the set point. Alarm 1 (P > SP), pin #1 (gray), is active when the red LED is ‘ON’ indicating that the pressure is above the set point. Alarm 2 (P < SP), Pin #2 (brown), is active when the green LED is ‘ON’ indicating that the pressure is below the set point.
Character Description Valid Inputs: m Most Significant Digit Of Mantissa 1-9 d Decimal Digit 0-9 e Exponent 0-5 Command Terminator (carriage return) 3.4.2 N/A Interrogation Commands. Command Description Format Sample Response Get Device ID ID Digital AVC Get Current Pressure if A0 is set, current Set Point if A2 is set, heater potentiometer setting if A3 is set P Pa: 1.23456e+0 Torr Get Relay Status RS 1,R1:ON Get Setpoint S1 SP1: 1.
digit exponent before being accepted. There are no limit checks on the data; the user is free to choose any value appropriate to his use of the instrument. If the command syntax is not met or if the number is out or range, the Digital AVC will respond with the ASCII codes for ?, and the command will be ignored. 3.4.
3.6 Gauge Tube Operating Principle Operation of the Hastings gauge tube is based on a low voltage AC bridge that heats a noble metal thermopile. A change in pressure in the gauge tube changes the molecular collision rate and therefore the thermal conduction of the gas or gas mixture surrounding the thermopile. This results in a temperature shift in the AC heated thermocouples A and B (Fig. 6).
B. Turn the HTR potentiometer on the top panel until the either the voltage measured between pins 6, Analog Signal Common (violet) and 7, Pressure Signal Output (yellow) reads the voltage corresponding to the pressure as read on the Pressure Vs. Voltage chart for the tube being measured or, if using serial communication, until the proper pressure is read while using the streaming P1 command. C. THE LOW END is now adjusted. NOTE: If re-calibration is required you must repeat the High End adjustment first.
4.0 Warranty 4.1 Warranty Repair Policy Hastings Instruments warrants this product for a period of one year from the date of shipment to be free from defects in material and workmanship. This warranty does not apply to defects or failures resulting from unauthorized modification, misuse or mishandling of the product. This warranty does not apply to batteries or other expendable parts, nor to damage caused by leaking batteries or any similar occurrence.
