SRS501 User s manual

Transcription

1 SRS501 User s manual 1. Function Function of the device is measurement of angular rate projection. 1.1 Specification: in steady state power consumption: < 6 watt; time of functional ready no more 3 seconds; range of linear measured angular rate: ±250 deg/sec; range of measured angular rate with keep sign rate : ±500 deg/sec; the device mass: 0.4 kg. 1.2 Figure 1 shows the exterior of the device. Figure 1 2. Connection to external circuit 2.1 Connection of the device to external circuit implements over pins (Figure 2). Figure 2

2 2.2 Purposes of the device s pins. Purpose Pin Designation Description Input power supply 1, 2 +5V Power supply 5V ±5%. 3, 4 GND +5V Max current 3А. Serial interface 5 Line A Line A RS485 interface EIA Line B Line B RS485 interface EIA-485 Synchronization 7 TR+ Input for synchronization measurement (input RS485 8 TR- dif. signal EIA-485). Other 9 Case This pin connects to case of device Table 1 Attention! The device doesn t have protection from wrong connection. Connection error or over-voltage delivery can be the cause of device failure or its quick degradation. Time between device switching off and again switching on (and other) must be not less 1 minute. 2.3 Device power on and power off. In order to switch the device on need to supply power (5±0,25V) to the pins 1, 2 +5V and to the pins 3, 4 GND(+5V) of the device. In order to switch the device off need to remove power from the pins 1, 2 +5V and from the pins 3, 4 GND(+5V) of the device. It is recommended to use isolated from outside circuit power supply.

3 2.4 Figure 3 shows the scheme of device(s) connection. RS485 A+ B- 5 A+ 6 B- PC/CPU GND 3 GND 4 GND +5V 1 +5B 2 +5B SRS A+ 6 B- GND 3 GND 4 GND +5V 1 +5B 2 +5B SRS-501 Figure Figure 4 shows the scheme of device(s) connection with external synchronization signal input. RS485 A+ B- 5 A+ 6 B- T+ T- 7 TR+ 8 TR- T+ T- T+ T- GND 3 GND 4 GND PC/CPU +5V 1 +5B 2 +5B SRS A+ 6 B- 7 TR+ 8 TR- GND 3 GND 4 GND 1 +5B +5V 2 +5B Figure 4 SRS-501

4 3 Description of interface For connection to external equipment in the device use RS-485 interface. There are three modes of output data to external equipment in the device. Mode I: Output data through RS-485 interface with using exchange data protocol SSP 2.0. Mode II: Output data through RS-485 interface as response to a sync pulse. Mode III: Output data through RS-485 interface by a signal of internal timer with customizable frequency. Switching modes is performed automatically. If on entry synchronization signals are absent (sync pulse 1 -> 0 or DC 0 ) then protocol SSP 2.0 is working. When a sync pulse comes or on entry synchronization DC level 0 is hold, protocol SSP disable and device begin to transmit data in the form frame in compliance with table 2 or table Synchronization of measurement. In the mode II the measurement synchronization is performed by rising edge of sync pulse. Processing data is performed, data frame is generated and after constant time (Table 4) data frame is transmitted through interface RS-485. In the mode III clocking of measurement is performed by internal timer. Time from measurement to transmitting first byte of frame is constant (Table 4). Period of measurement can be changed by writing of coefficient by means of command PUT in mode I (address 34). In modes II and III baud rate of interface RS-485 can be changed from 9.6 Kbaud to Kbaud by writing of coefficient by means of command PUT in mode I (address 32). 3.2 Mode I description (protocol SSP 2.0) The device is attached to PC from asynchronous serial interface RS-485. Rate of exchange is baud only; 8 bit; 2 stop-bits without parity. Exchange data with device performs by protocol SSP 2.0 (Simple Serial Protocol). Maximum time of reaction on command is 1000 μsec (between receive and transmit). Maximum frequency of sampling is 200 Hz. The main purpose of this mode is configuring device s factory s and user s parameters. There is the simple description of the protocol SSP for a device TRS-500 in appendix Description of device operation in modes II and III The device TRS500 output data through serial interface RS-485 as response to an external sync pulse or by a signal of internal timer. Baud rate is set up in mode I (protocol SSP, table 7). Format: 8 bits, 2 stop-bits, no parity. In the mode II the measurement is performed by rising edge of sync pulse. Transmitting data begins after removal sync pulse.

5 There are formats of output packet (device work in mode II or III) in the table 2 and table 3. Table 2 shows the structure of base packet Table 2 Byte Name Description Size [bit] 0 Header Header: value equal 0xC0C0 (192d) 16 2 Angle rate Angle rate, deg/s. 32-bit value in format floating-point (float). In moment of coming 32 sync pulse. 6 CRC bit CRC-CCITT. Calculate by bytes 2 5 only 16 Table 3 shows the structure of extended packet Table 3 Byte Name Description Size [bit] 0 Header Header: value equal 0xC0C0 (192d) 16 2 Angle rate Angle rate, deg/s. 32-bit value in format floating-point (float). In moment of coming sync pulse. 32 [ 6 ] [ 6+2 T ] [ 6+2 T +2 FC ] Temperature case of the device Packet counter * Time-counter from start-up of the device LSB = 0.1ºC. 16-bit value in format signed short 16-bit unsigned integer value 16 LSB 8,68055 μsec (1/115200). 32-bit value in format unsigned integer 6+2 T +2 FC +4TM CRC bit CRC-CCITT. 16 T, FC, TM - bits of register for configuration of extended packet, see table 8. [] this field adds to base packet if only corresponded bit (T or FC or TM) set to one. 3.4 Time parameters of interface Figure 5 shows diagram of work interface

6 Figure 5 diagram of work interface. There are time parameters of interface in the table 4. Table 4 Designation Description Value min max t1 Time from transmission last byte request to start transmission first byte of packet, μsec 1000 t2 Time from falling edge of sync pulse to start transmission first byte of packet, μsec * t3 Time from giving fixed level on input synchronizing circuit to start transmission first byte of packet, msec 500 t4 Time from start of measurement to start transmission first byte of packet, μsec * t5 Time from start of measurement to start transmission first byte of packet, msec 3 t6 Time from falling edge of sync pulse to start of measurement, μsec 2 Tsync Period of external sync pulse See table 5 Tclock Period of signals internal timer See table 5 tp Sync pulse duration, μsec Тreq Request period (GET) when simultaneous request three parameters, μsec 5 * - For baud rate Kbaud. When baud rate decrease this time increase (for 9.6 Kbaud 375 μsec). Request frequency in mode I is no more 200 Hz. There is dependence request frequency from baud rate of interface RS485 in the table 5.

7 Table 5 Baud rate RS-485 Sync pulse-repetition frequency, Sync pulse period, μsec by sync pulse, Hz Kbaud min max min max 9,6 25, ,4 20, ,2 12, ,4 6, ,6 5, ,2 2, ,4 1, ,8 0, ,6 0,

8 Appendix 1 Description of the protocol SSP For division of flow of data, the protocol SSP uses framing RFC1055 (SLIP). Every frame begins and ends with symbol FEND (0xс0). If packet of data included symbol FEND then this symbol is change to FESC TFEND (0xdb 0xdc). If packet of data included symbol FESC (0xdb) then this symbol is change to FESC TFESC (0xdb 0xdd). Any symbol following behind FESC, except TFEND or TFESC, is wrong. The symbols TFEND and TFESC is just data, if before them is absent symbol FECS. The protocol SSP doesn t support arbitration of bus between some master devices. Every frame include packet SSP. General format of packet SSP is: dest, srce, type,...data..., crc0, crc1 DEST SRCE TYPE DAT0.. DATN CRC0 CRC1 dest one byte is address of slave device, which transmit data. Value 0 for dest is reserve for broadcast. Value FEND or FESC for dest is wrong. Default address is 100(0x64). srce one byte is address of master device, which request data. Value 0 for dest is reserve for use in future. Value FEND or FESC for srce is wrong. type one byte include two fields: ss.pktype Low six bits (pktype) are type packet. High two bits are additional data, which can mean special data (if not use, ss=0 ). Some values of pktype specifies as standard values. crc0 и crc1 two bytes is CRC-16. CRC is received by low byte forward, and it includes all previous bytes starting with dest until last byte of data. Ignore any packet with wrong CRC. Example calculates CRC on C language follows below. Initial value shift register crc will must be equal 0xFFFF(hex). #define mask 0x1021 unsigned short updcrc(unsigned short crc, unsigned short c) { unsigned char i; c <<= 8; for (i = 0; i < 8; i++) { if ((crc ^ c) & 0x8000) crc = (crc << 1) ^ mask;

9 else crc <<= 1; c <<= 1; } return crc; } Description command of SSP protocol PING Command PING. Format > 0.0 (ss.pktype), 0x00 (Hex) DEST SRCE 0x00 CRC0 CRC1 Response of device is ACK. Format > 1.2 (ss.pktype) 0x42 (Hex) DEST SRCE 0x42 CRC0 CRC1 Description: test packet without data, for check device communication. Example: Master device with address 0x02 sends command PING by slave device with address 0х64. Request -> DEST SRCE PING CRC0 CRC SSP Dec 0x64 0x02 0x00 0x55 0xED SSP Hex 0xC0 0x64 0x02 0x00 0x55 0xED 0xC0 (SSP+RFC) Hex Response -> DEST SRCE ACK CRC0 CRC SSP Dec 0x02 0x64 0x42 0x94 0x0D SSP Hex 0xC0 0x02 0x64 0x42 0x94 0x0D 0xC0 (SSP+RFC) Hex INIT Command INIT. Format > 0.1 (ss.pktype), 0x01 (Hex) DEST SRCE 0x01 CRC0 CRC1 Response of device is ACK. Format > 0.2 (ss.pktype), 0x02 (Hex) DEST SRCE 0x02 CRC0 CRC1

10 Description: Optional command, use for compatibility with SSP2.0. Example: Master device (Master) with address 0х02 sends command INIT by slave device (Slave) with address 0х64. Request -> DEST SRCE INIT CRC0 CRC SSP Dec 0x64 0x02 0x01 0x74 0xFD SSP Hex 0xC0 0x64 0x02 0x01 0x74 0xFD 0xC0 (SSP+RFC) Hex Response -> DEST SRCE ACK CRC0 CRC SSP Dec 0x02 0x64 0x02 0x50 0x45 SSP Hex 0xC0 0x02 0x64 0x02 0x50 0x45 0xC0 (SSP+RFC) Hex ID Command ID. Format >0. 8 (ss.pktype), 0x08 (Hex) DEST SRCE 0x08 CRC0 CRC1 Response of device is ACK + ASCII string. Format > 0.2 (ss.pktype), 0x02 (Hex) DEST SRCE 0x02 ASCII ASCII CRC0 CRC1 Description: Identification device Example: Master device (Master) with address 0х02 sends command ID by slave device (Slave) with address 0х64. Slave device return message ACK+ PNSK Request -> DEST SRCE ID CRC0 CRC SSP Dec 0x64 0x02 0x08 0x5D 0x6C SSP Hex 0xC0 0x64 0x02 0x08 0x5D 0x6C 0xC0 (SSP+RFC) Hex Response -> DEST SRCE ACK ASCII ASCII ASCII ASCII ASCII ASCII SSP Dec 0x02 0x64 0x02 0x50 0x4E 0x53 0x4B 0x34 0x30 SSP Hex 0xC0 0x02 0x64 0x02 0x50 0x4E 0x53 0x4B 0x34 0x30 (SSP+RFC) ASCII ASCII ASCII ASCII CRC0 CRC SSP Dec 0x2D 0x30 0x31 0x38 0xEC 0x8C SSP Hex 0x2D 0x30 0x31 0x38 0xEC 0x8C 0xC0 (SSP+RFC)

11 WRITE The command WRITE. Format > 0.7 (ss.pktype), 0x07 (Hex) DEST SRCE 0x07 ADR DAT0 DATN CRC0 CRC1 4 byte 4 byte 4 byte The field ADR address array 32 bits long, it is transferred lower significant bit forward: BYT0 BYT1 BYT2 BYT3 The field DAT one field array data 32 bits long, it is transferred lower significant bit forward: BYT0 BYT1 BYT2 BYT3 Response of device is ACK. Format > 1.2 (ss.pktype), 0x42 (Hex) DEST SRCE ACK CRC0 CRC SSP Dec 0x02 0x64 0x42 0x94 0x0D SSP Hex 0xC0 0x02 0x64 0x42 0x94 0x0D 0xC0 (SSP+RFC) Hex Description: Writing of data array in the device. In product is used only for the definition of the new address. Example: The master device with address 0х02 send command WRITE the slave device for change of the address on 0х63. Request -> DEST SRCE WRITE ADR0 ADR1 ADR2 ADR SSP Dec 0x00 0x02 0x07 0x00 0x00 0x00 0x00 SSP Hex 0xC0 0x00 0x02 0x07 0x00 0x00 0x00 0x00 (SSP+RFC) Hex DAT0 DAT1 DAT2 DAT3 CRC0 CRC SSP Dec 0x63 0x00 0x00 0x00 0x20 0x79 SSP Hex 0x63 0x00 0x00 0x00 0x20 0x79 0xC0 (SSP+RFC) Hex Response -> DEST SRCE ACK CRC0 CRC SSP Dec 0x02 0x63 0x42 0x03 0x94 SSP Hex 0xC0 0x02 0x63 0x42 0x50 0x45 0xC0 (SSP+RFC) Hex The command with the memory address different from zero is considered an error.

12 GET The command GET. Format > 0.4 (ss.pktype), 0x04 (Hex) DEST SRCE 0x04 ADR1 ADRN CRC0 CRC1 2 byte 2 byte The field ADR address array 16 bits long, it is transferred lower significant bit forward: BYT0 BYT1 The field DAT variable by address ADR 32 bits long, it is transferred lower significant bit forward: BYT0 BYT1 BYT2 BYT3 Response of device is ACK. Format > 0.2 (ss.pktype), 0x02 (Hex) DEST SRCE 0x02 DAT1 DATN CRC0 CRC1 4 byte 4 byte 4 byte Description: Data read from the device The list of accessible addresses read on the command GET Address (dec) 0 Table 6 Description Unit Format Note Rate obtained on the last period of measurement. deg/sec float 3 Temperature case of the device LSB = 0.1ºC signed long 12 Setup a bandwidth Kf Time-counter from start-up of the device Code for setup baud rate of interface RS-485 in modes II and III Register for configuration of extended packet Devisor of internal timer frequency LSB 8,68055 μsec (1/115200) See table 7 See table 8 Div unsigned long unsigned long unsigned long unsigned long unsigned long Supplemental information Kf * coefficient of recursive filter, 1 < Kf < 1000 F average 1,5Kf Watch overflow Default set to zero f = /Div * zero value switch recursive filter to averaging in period between external or internal sync pulse ( Tsync or Tclock in table 4). This feature can be used in modes II and III. There is correspondence of code by baud rate Rs-485 in the table 7. Table 7 Code Baud rate RS-485 in modes II and III, KBaud Note 95 9, ,2

13 23 38, , ,2 Default value 3 230, , ,6 Table 8 shows structure register which used for configuration of extended packet. Table 8 Bit number Description Note 0 T 0- temperature data do not add to packet 1- temperature data add to packet 1 FC 0- count-packet data do not add to packet 2 TM 1- count-packet data add to packet 0- time-count data do not add to packet 1- time-count data add to packet 3 31 Not used On one command GET reading of value some variables is admitted. Call to not existing addresses is considered an error. Example: The master device with address 0х02 read information to addresses 24 and 0 from the slave device with address 0х64. The slave device return ACK+data( )= adr24+data( )=adr0. Request -> DEST SRCE GET ADR0.24 ADR1.24 ADR0.0 ADR1.0 CRC0 CRC SSP Dec 0x64 0x02 0x04 0x18 0x00 0x00 0x00 0x30 0x1F SSP Hex 0xC0 0x64 0x02 0x04 0x18 0x00 0x00 0x00 0x30 0x1F 0xC0 (SSP+RFC) Response -> DEST SRCE ACK DAT0.3 DAT1.3 DAT2.3 DAT SSP Dec 0x02 0x64 0x02 0x7D 0x9C 0x16 0x44 SSP Hex 0xC0 0x02 0x64 0x02 0x7D 0x9C 0x16 0x44 (SSP+RFC) DAT0.24 DAT1.24 DAT2.24 DAT3.24 CRC0 CRC SSP Dec 0x7D 0x03 0x4D 0x3B 0x78 0xAD SSP Hex 0x7D 0x03 0x4D 0x3B 0x78 0xAD 0xC0 (SSP+RFC) PUT The command PUT. Format > 0.5 (ss.pktype), 0x05 (Hex) DEST SRCE 0x05 ADR1 DAT CRC0 CRC1 2 byte 4 byte The field ADR address of variable 16 bits long, it is transferred lower significant bit forward:

14 BYT0 BYT1 The field DAT one field array of data 32-bit long, it is transferred lower significant bit forward: BYT0 BYT1 BYT2 BYT3 Response of device is ACK. Format > 0.2 (ss.pktype), 0x02 (Hex) DEST SRCE 0x02 CRC0 CRC1 Description: Write setup variables to device. There is the list of accessible for write addresses by command PUT in the table 9 Table 9 Address Description Note (dec) 12 Setup bandwidth 32 Code for setup baud rate of interface RS-485 in modes II and III 33 Register for configuration of extended packet 34 Devisor of internal timer frequency See table 6 Setup variables are saved in nonvolatile memory of the device. All this variables are unsigned long and transferred lower significant bit forward. Access to nonexistent address is error. Example: The master device with address 0х02 write code for setup baud rate RS Kbaud to address 32 of the slave device with address 0х64. Request -> DEST SRCE GET ADR0 ADR1 DAT0 DAT1 DAT2 DAT3 CRC0 CRC SSP Dec 0xC0 0x64 0x02 0x05 0x21 0x00 0x07 0x00 0x00 0x00 0x9c 0xee 0xC0 (SSP+RF) Response -> DEST SRCE ACK CRC0 CRC SSP Dec 0xC0 0x02 0x64 0x02 0x50 0x45 0xC0 (SSP+RFC)Hex Device ignore any misaddress and damage packet. Damage packet packet length lower 5 byte and/or CRC error.