Document title: DE RIMS mode SFD Project: DE NDADS Datatype: RIMS Super-EID: DOCUMENT There may be other documents also identified by this super-EID. NDADS filename: DOCUMENT_RIMS_RIMSMODE.SFD TRF entry: b46609.txt in NSSDC's controlled digital document library, Feb. 1998. Document text follows: ---------------------- TYPE_OF_FILE_NAME: RIMS Instrument Mode Listing FILE_ATTRIBUTES: ASCII Text file TYPE_OF_FILE_DESCRIPTION: Each line of ASCII text represents one minor mode B command to the RIMS instrument. The file name is RIMSMODE.TXT DESCRIPTION: RIMSMODE file contents DATE: The year and daynumber is coded as (YEAR-1980) * 1000 + DAYNUMBER TIME: The universal time of day (HHMMSS). INSTRUMENT MODE: Commands to the RIMS instrument coded in an alphanumeric string of up to 10 characters. EXAMPLE_TEXT: 1294 50000 IMSON 1294 50016 T816E00 1294 80400 STOPIT 1294 85800 IMSON 1294 85816 T816E00X 1294 85820 T816E00A 1294 85824 T816E00B 1294 85828 T816E00C 1294 85832 T816E00D 1294 151600 STOPIT SUMMARY_INFORMATION: B: OPERATION_MODE: The RIMS instrument, being programmable by spacecraft major and minor mode commands, operated in a variety of survey modes during the experiment lifetime. The operating sequence is controlled by an internal memory in the CEA which is programmed by ground command. The RIMS commonly performed two basic operational functions during the mission: 1) The RPA voltage is swept over a selected range for a given mass and, 2) The RPA voltage is set to zero and a sweep is made over a selected mass range. There are several variations of these modes, several specialized modes, and several combinations of sweeps, aperture biasing, and cycling patterns. Minor Mode B Commands: 1 32-bit serial word that is received and stored in a command register. This command is used exclusively for loading the 32-word instrument memory. The sequence of 32 words sets up the IMS and RPA steps that will be executed during the instrument cycle. The following is a summary of the RIMS nominal operating modes: IMSON,RPAON,APPON: "Turn-on" and initiation commands. STOPIT: "Turn-off" command. HIXXZ: A family of modes in which the instrument is measuring only one mass pair and concentrating on either high mass or angular resolution. The two unspecified locations in the mnemonic denoted by X will specify the heavier of the pair while the location denoted by Z refers to an RPA program. XVXXZ: A family of survey modes in which the instrument splits its observing pattern between the H+/He+ mass pair and one other mass pair. The definition of the unspecified location is the same as in the previous case. The total cycle time is 16 sec. SXYYZ: The alternate memory is used to observed the H+/He+ pair and the normal memory to observe another mass pair. The XX denotes the heavier of the mass pair under normal memory control. Each mass pair is sampled for 8 seconds. Total cycle time is 16 seconds. TXYYZ: A survey mode which is similar to the previous survey model with the exception of the sequencing pattern. In this case, the H+/He+ setting is maintained for 8 sec with an RPA cycle each 0.25 sec. In the subsequent 8-sec half of the cycle time, the instrument toggles between the alternate mass pairs each 0.25 sec. The total cycle time is 16 sec. MXXYY: A mass sweep mode starting at mass XX and ending at mass YY. The specified mass numbers of those of the heavy mass channel. The lower mass channel with be operating and measuring mass species of 1/4 of the specified high mass values. Note: The sweep may not be continuous within the specified range if prior instrument experience has indicated that certain mass numbers are unpopulated. The cycle time is 0.5 sec. CXXYY: A mass sweep mode with interspersed RPA analysis of the H+/He+ pair. The cycle time is 16 sec. SHXXY: A special mode for high latitude studies. The three ions O+, H+, and He+ are measured with RPA scans for each. The cycle time is 1/2 second. SSZZZ: Special science modes designed after launch. Contact RIMS science team. PLPHN: Plasma mode used to investigate spacecraft/plasma interactions. Geophysical data may be available, but will require special interpretation. N is the program number. INSTR: Instrument check out, test, and calibration modes. Note that the instrument may be operating with an additional potential applied to the entrance aperture. The start-up command APPON normally indicates the start of an aperture bias sequence although exceptions do exist within the data set. The following commands identify the applied bias voltage: NAMMAP2X -2 volts NAMMAP4X -4 volts NAMMAP8X -8 volts PH20AAAA -2 volts PH20ADTD -2 volts PH40AAAA -4 volts PH40ADTD -4 volts PH80AAAA -8 volts PH80ADAA -8 volts PH80ADTD -8 volts PL80ADAA -8 volts HI04A02X -2 volts HI04A03X -4 volts HI04A04X -8 volts SH16M02X -8 volts SSNV801X -8 volts SSN8V01X -8 volts T816Q03X -2 volts T816Q04X -4 volts T816205X -8 volts SS04P01 -8 volts STUDIES OF THE RIMS DATA SET SHOULD BE CONDUCTED ONLY WITH A THOROUGH UNDERSTANDING TO THE RIMS OPERATIONAL MODES AND THE INSTRUMENT RESPONSE TO THESE MODES. The convention of naming modes as given above were generally but not rigorously followed. i.e., there may be times in which a mass scan mode MXXYY alternated with measurement of H+/He+.