1.0 COMMAND SUMMARY CONTROL CODES: FUNCTION 6 Azimuth CW one step 4 Azimuth CCW one step 8 Elevation UP one step 2 Elevation DOWN one step > Move gyro compass heading up 1/6 degree < Move gyro compass heading down 1/6 degree Adddd{} Move AZ to ddd.d deg. true or magnetic +dddd{} Move AZ to ddd.d deg. without unwrap check Bdddd{} Set ships heading to ddd.d degrees C Step Track ON D Step Track and Test Mode OFF Eeee{} Move EL to ee.e degrees F Toggle auto unwrap ON/OFF G Toggle Gyro compass reference ON/OFF (true/mag) Jrrrr{} Move azimuth to ship relative position Kaaaa{} Search clockwise aaaa Azimuth steps /aaaa{} Search counter clockwise aaaa Azimuth steps Lssss{} New signal strength update Nnnn{} Set number of signal strength updates (1-255) Ox{} Output data to EME equipment =nnn{} Set search speed to nnn x .156 steps/sec. T Calibrate flux gate sensor U Force cable unwrap W Write parameters to NV RAM (Lockout Protected) Xnnn{} Set azimuth step track size to nnn steps (1-255) Ynnn{} Set elevation step track size to nnn steps (0-255) Z Initialize Az/El counters (soft reset) ! Enable NVRAM writes # Mute, disables PCU command echo. ^ Software Test Mode ON esc Cancel Pending Command MONITOR CODES FUNCTION PCU RESPONSE H Rel Az,Ship Heading "RrrrrHdddd,CR,LF,">" I Input EME status "Ixx",CR,LF,">" M Parameter Dump Xnnn Ynnn Nnnn (Step track param) Xnnnn Ynnnn (Calib offset) Xnnnn Ynnnn (Calib gain) P Az/EL Position "EeeeAdddd",CR,LF,">" Q Flux gate output Xnnnn Ynnnn Mdddd (Magnetic) or Xnnnn Ynnnn Bdddd (True) S PCU Status "Snn",CR,LF,">" V Software Version "MK III VER N.N",CR,LF,">" % Signal strength "Lssss"CR,LF,">" & Error Status "&e"CR,LF,">" ABBREVIATIONS: eee = Elevation angle. 000 to 900. dddd = True/Magnetic Azimuth 0000 to 3599 range aaaa = Search range in Azimuth steps rrrr = Relative azimuth 0950 to 6250 range ssss = ASCII hex signal strength (0000-FFFF) x = ASCII hex I/O data {} = Carriage return nnn = ASCII decimal number 0 to 255 nn = System Status two ASCII characters defined below e = Error Status one ASCII character defined below 2.0 CONTROL CODE DETAILS 6 Azimuth CW one step. One step equals 0.351 degrees in True/Magnetic AZ mode, 0.234 degrees in Relative AZ mode. Normal / Mute PCU Response: None 4 Azimuth CCW one step. One step equals 0.351 degrees in Magnetic AZ mode, 0.234 degrees in Relative AZ mode. Normal / Mute PCU Response: None 8 Elevation UP one step. One step equals 0.15 degrees. Normal / Mute PCU Response: None 2 Elevation DOWN one step. One step equals 0.15 degrees. Normal / Mute PCU Response: None >,< Move gyro compass heading up, down 1/6 degree. Used to update gyro compass heading for use with external azimuth reference (gyro compass or external flux gate compass. Normal / Mute PCU Response: None Adddd{} Move AZ to ddd.d degrees magnetic. Sets true/magnetic AZ mode, clears Relative AZ mode status flag (bit 4 word 2). Azimuth stabilization, Unwrap and SKY search are enabled in magnetic AZ mode. Unwrap check is performed on this command. Antenna will move to opposite wrap if command drives antenna within 45 degrees of wrap limit. Normal PCU Response: Echoes "Adddd" as characters are entered, Echoes CR,LF,">" when command is accepted. Normal command acceptance latency is 25 mS. Mute PCU response: CR,LF,">" when command is accepted. +dddd{} Same as Adddd{} except no Unwrap check is performed. Bdddd{} Set ships compass heading to ddd.d degrees. Sets Gyro compass reference flag (bit 4 word 1) and Heading Valid flag (bit 3 word 1). Resets calculated azimuth position (P command) to ships heading + azimuth relative position modulo 360.0 degrees. The commands ">" and "<" must be used to update ships heading in 1/6 degree increments as the ship turns in this mode. Normal PCU Response: Echoes "Bdddd" as characters are entered, Echoes CR,LF,">" when command is accepted. Normal command acceptance latency is 25 mS. Mute PCU response: CR,LF,">" when command is accepted. C Step track ON. Sets Steptrack ON status flag (bit 3 word 1). Enables step track movements synchronized with "L" signal strength updates. Default state OFF. Normal PCU Response: Echoes "C",CR,LF,">" . Mute PCU response: None D Step track and Test mode OFF. Clears Steptrack ON status flag (bit 3 word 1). Disables step track movements. Normal PCU Response: Echoes "D",CR,LF,">" . Mute PCU response: None Eeee{} Move EL to ee.e degrees. Normal PCU Response: Echoes "Eeee" as characters are entered, Echoes CR,LF,">" when command is accepted. Normal command acceptance latency is 25 mS. Mute PCU response: CR,LF,">" when command is accepted. F Toggle auto unwrap ON/OFF. Toggles Auto Unwrap ON status flag (bit 5 word 1). Enables/Disables auto unwrap. Default state is OFF. Normal PCU Response: Echoes "F",CR,LF,">" . Mute PCU response: None G Toggle Gyro Compass Reference ON/OFF. Toggles bit 4 in status word 1. Default state is OFF. In gyro compass reference mode, antenna bearing is computed as Ship Heading + Relative Position. This result is used as the long term reference for the azimuth stabilization loop. Normal PCU Response: Echoes "G",CR,LF,">" . Mute PCU response: None Jhhhh{} Move azimuth to ship relative position. Sets Relative AZ mode status flag (bit 4 word 2). Relative AZ mode is intended for external azimuth stabilization and diagnostic purposes. Azimuth stabilization, Unwrap and SKY search are disabled in relative AZ mode. Default AZ mode is relative. Normal PCU Response: Echoes "Jhhhh" as characters are entered, Echoes CR,LF,">" when command is accepted. Normal command acceptance latency is 25 mS. Mute PCU response: CR,LF,">" when command is accepted. Kaaaa{} Search clockwise aaaa Azimuth steps for satellite signal. Sets Searching status flag (bit 0, word 2). Allowed in True/Magnetic AZ mode only. Search is terminated by "L" update, "A" or "+" position command or end of search. If "L" update is send, antenna is stabilized at the current magnetic azimuth position. Normal PCU Response: Echoes "Kaaaa" as characters are entered, Echoes CR,LF,">" when command is accepted. Normal command acceptance latency is 25 mS. Mute PCU response: CR,LF,">" when command is accepted. /aaaa{} Search counter clockwise aaaa Azimuth steps for satellite signal. Same as Kaaaa except search direction is down. Lssss{} Signal strength update. Used for Step track and Search functions. Signal strength information is sent as one to four ASCII hexadecimal digits in the range of 0 to FFFF. Leading 0's are ignored. The resolution should be sufficient to detect the smallest step size expected. Usually 0.1 to 0.3 dB is sufficient. A non zero signal strength update terminates a "K" or "/" search. Normal PCU Response: Echoes "Lssss" as characters are entered, Echoes CR,LF,">" when command is accepted. Normal command acceptance latency is 25 mS. Mute PCU response: CR,LF,">" when command is accepted. Nnnn{} Set number of signal strength updates to accumulate for each trial step for step track operation. "N" should be set for a 5 second step track interval (nnn = 5 seconds / update rate). Allowable range is 1 to 255. Normal PCU Response: Echoes "Nnnn" as characters are entered, Echoes CR,LF,">" when command is accepted. Normal command acceptance latency is 25 mS. Mute PCU response: CR,LF,">" when command is accepted. Ox{} Output data to EME equipment. Changes logic state of output lines DO0, DO1 and DO2. Data is sent as ASCII hexadecimal. Allowable range of x is "0" to "F" (bit 3 is ignored). Current output status is reported in first character of "I" command. Normal PCU Response: Echoes "Ox" as characters are entered, Echoes CR,LF,">" when command is accepted. Normal command acceptance latency is 25 mS. Mute PCU response: CR,LF,">" when command is accepted. =nnn{} Set search speed to nnn x .156 azimuth steps per second. Allowable range is 0 to 255. Normal PCU Response: Echoes "=nnn" as characters are entered, Echoes CR,LF,">" when command is accepted. Normal command acceptance latency is 25 mS. Mute PCU response: CR,LF,">" when command is accepted. T Calibrate flux gate sensor. Installation calibration command, intended for supervised use only. Recommended to be performed at time of pedestal installation to compensate for any changes in the magnetic signature of the pedestal during shipping. Moves antenna from +225 degrees to -225 degrees relative (5850 to 1350). Measures maximum and minimum X and Y flux gate readings to calculate X and Y offsets and gains. Must be followed by "!W" commands to save calibration results. Normal / Mute PCU Response: Echoes "T",CR,LF,">". Echoes " COMP COMPLETE ",CR,LF,">" or " COMP RANGE ERROR ",CR,LF,">" OR " COMP GAIN ERROR",CR,LF,">" when compensation operation is complete. U Force cable unwrap. Allowed only in Magnetic AZ mode and only if relative AZ position is >5850 or < 1350. Sets Unwrap status flag (bit 2, word 1). Normal / Mute PCU response: Echoes "U",CR,LF,">" if in Magnetic AZ mode and AZ position is between 1350 and 5850. No echo if unable to unwrap. W Write step track parameters and Flux Gate calibration constants to NV RAM (values read out by "M" command). Requires NVRAM write enable command (!) to be issued within the last 6 seconds to enable this function. Normal / Mute PCU response: Echoes "W",CR,LF,">" after normal command latency of 25 ms. Echoes " LOCKOUT ERROR",CR,LF,">" if NVRAM write enable command has not been sent within 6 seconds. Xnnn{} Set azimuth step track size to nnn steps. One step is 0.351 degrees. Allowable range 1 to 255. Total Azimuth step size is further modified by present elevation position as follows: 0 - 70 degrees elevation = 1 x nnn x 0.351 degrees 70 - 75 degrees elevation = 2 x nnn x 0.351 degrees 75 - 85 degrees elevation = 3 x nnn x 0.351 degrees Normal PCU Response: Echoes "Xnnn" as characters are entered, Echoes CR,LF,">" when command is accepted. Normal command acceptance latency is 25 mS. Mute PCU response: CR,LF,">" when command is accepted. Ynnn{} Set elevation step track size to nnn steps. One step equals 0.15 degrees. Allowable range is 0 - 255 steps. Setting "Y" to zero disables elevation step track doubling the speed of the azimuth step track. This is the recommended mode of operation for the majority of time. Normal PCU Response: Echoes "Ynnn" as characters are entered, Echoes CR,LF,">" when command is accepted. Normal command acceptance latency is 25 mS. Mute PCU response: CR,LF,">" when command is accepted. Z Initialize Az/El counters. Sets Initializing status flag (bit 1 word 2). Stops any calibration or unwrap operation in progress. Resets relative AZ position, Elevation position, and Level platform zero. Re-zeros Azimuth, Level and Cross Level rate sensors. Restores PCU to echo mode. Initialization time is 120 seconds. Normal PCU Response: Echoes "Z",CR,LF,">" when command is entered. Mute PCU response: None ! Enable NV RAM writes. See "W" command for details. PCU response: None. # Mute PCU responses. Truncates the character echo for all command functions. PCU response: None. ^ Enable Test Mode. Increases speed of tilt sensor response. Converts "8", "6", "4" and "2" commands from antenna movements to tilt sensor trim movements. Test mode is disabled by the "Z" or "D" commands or RESET. PCU response: None. esc (ASCII 27) Cancels pending Control or Monitor command (Monitor commands can only be pending durring inititialization). Normal PCU response: esc,CR,LF,">" Mute PCU response: None. 3.0 MONITOR CODE DETAILS H Relative AZ / Ships Heading position report. Reports simultaneous value of Antenna Relative position and Ships heading position in tenths of degrees. The allowable range of values for Relative azimuth position is 0950 to 6250. The allowable range of values for Ships heading is 0000 3599. PCU Response: "RrrrrHdddd",CR,LF,">" after normal command response latency of up to 25 mS. I Input EME status. Response is 2 ASCII hexadecimal characters representing the status of the peripheral interface output lines (MSD) and interface input lines (LSD). The allowable range of values is 00 to 7F. PCU Response: "Ixx",CR,LF,">" after normal command response latency of up to 25 mS. M Parameter Dump. Response is three lines of data representing the X,Y and N step track parameters, X and Y flux gate calibration offsets and X and Y flux gate gain calibration factors. PCU Response: "Xnnn Ynnn Nnnn",CR,LF, (Step track param) "Xnnnn Ynnnn",CR,LF, (Calibration offsets) "Xnnnn Ynnnn",CR,LF,">" (Calibration gains) Normal command response latency is 25 mS. LIMITATIONS: Diagnostic command only, must not be used during normal system operation. P Az/EL Position. Response is one line of ASCII decimal characters representing the antenna elevation and rate stabilized magnetic azimuth in tenths of a degree. Elevation range is 000 to 900. Azimuth range is 0000 to 3599. PCU Response: "EeeeAdddd",CR,LF,">" after normal command response latency of up to 25 mS. Q Flux gate output. Response is one line of ASCII decimal characters representing the present X and Y flux gate channel voltages and the present true or magnetic azimuth antenna position. X and Y ranges are 0000 to 4095, True/Magnetic azimuth range is 0000 to 3599. True azimuth is indicated by a B prefix, Magnetic azimuth is indicated by an M prefix. PCU Response: "Xnnnn Ynnnn Bdddd",CR,LF,">" in gyro reference mode, "Xnnnn Ynnnn Mdddd",CR,LF,">" in flux gate reference mode Normal command response latency is 25 mS. LIMITATIONS: Diagnostic command only, must not be used during normal system operation. S PCU Status. Response is two ASCII characters representing the system status according to the following table. This command can be issued at any time and is not locked out by pending I/O commands. PCU Response: "Snn",CR,LF,">" immediately upon receiving status request. nn Status Words: WORD1 WORD 2 Bit 0 = Near lower azimuth limit Bit 0 = Searching Bit 1 = Near upper azimuth limit Bit 1 = Initializing Bit 2 = Unwrap in progress Bit 2 = Error Detected Bit 3 = Steptrack On Bit 3 = Heading Valid Bit 4 = Gyro compass reference ON Bit 4 = Relative AZ mode Bit 5 = Auto Unwrap On Bit 5 = Azimuth Target Bit 6 = 1 Bit 6 = 1 Bit 7 = 0 Bit 7 = Elevation Target V Software Version. Response is ASCII string defining software model and version number. PCU Response: " MK III VER N.N",CR,LF,">" after normal command response latency of up to 25 mS. % Signal strength report. Average of last valid signal strength updates in ASCII Hex (0000 to FFFF range). PCU Response: "%ssss",CR,LF,">" after normal command response latency of 25 mS. & Error Status. Response is one ASCII character representing the error status according to the following table. Any error bit set causes the Error Detect bit (Bit 2, Word 2) in the Status report to be set. The Error Detect bit and all Error Status bits are latched until read with the "&" command. Reading the Error status clears all error bits and the Error Detect status bit. This command can be issued at any time and is not locked out by pending I/O commands. PCU Response: "&e",CR,LF,">" immediately upon receiving status request. e Error Word: Bit 0 = Encoder Gray Code Read Failure Bit 1 = Cross Level Rate Sensor Failure Bit 2 = Level Rate Sensor Failure Bit 3 = Azimuth Rate Sensor Failure Bit 4 = Cross Level Drive Failure Bit 5 = Level/Elevation Drive Failure Bit 6 = 1 Bit 7 = Azimuth Drive Failure 4.0 GENERAL NOTES The CR,LF,">" echo indicates that the PCU has accepted a command and is ready to process the next command. Any additional commands except the Status request "S" will not be accepted until after the PCU echoes CR,LF,">". Version 1.5B and later have a reduced initialization time that will allow the pedestal to accept commands and position the antenna 45 seconds after power ON or a "Z" command. The INIT flag in the status word still remains high for 120 seconds indicating the azimuth rate sensor bias is being adjusted and full stabilization accuracy may not be achieved under severe conditions until this flag clears. The end of the 45 second initialization period can be identified by the RELATIVE AZ MODE status flag (bit 4 word 2) changing from 0 to 1 or detecting that PCU responds to all other monitor commands. During the first 45 seconds of initialization, the PCU will not respond to most control commands or any monitor command except "S" until the initial 45 seconds have elapsed. Failure of the PCU to echo a command character indicates that it has ignored the request due to previous pending commands. Sending an escape character (ASCII 27) will clear any pending monitor or control command. The exact size of the azimuth step is 360/1024 degrees in Magnetic mode and 360/1536 degrees in Relative mode.  SEA TEL MODEL 1893 USER INTERFACE DESCRIPTION VERSION 1.5B 1