Product Description:
1.1 Appearance and installation dimensions
Dimensions ( mm ): 120 ± 0.1 × 120 ± 0.1 × 36 ± 0.1 (length × width × height);
Installation dimensions ( mm ): 94 ± 0.1 × 94 ± 0.1 (length × width), hole position 4 × Φ6.4 , as shown in Figure Picture 1
1.1 weight
Total product weight: 890g±20g .
1.2 Main performance parameters
The main performance parameters of the product are shown in Table 1 .
Table 1 Main performance parameters
| Serial number | Test items | unit | Technical requirements |
| 1 | Dimensions | mm | 120×120×36 |
| 2 | Startup time | s | 3 |
| 3 | Bias | (°)/h | ≤0.25 |
| 4 | Zero bias stability at room temperature (constant temperature) | (°)/h | ≤0.005 ( 10s smoothing) ≤0.002 ( 100s smoothing) |
| 5 | Constant temperature bias repeatability | (°)/h | ≤0.0 01 Constant temperature (-40 ℃ ~70 ℃ ) |
| 6 | Bias repeatability in different temperature ranges | (°)/h | Range < 0.02 (maximum value minus minimum value) |
| 7 | At constant temperature ( -40°C~70°C ) Normal temperature: Select 7 groups for measurement -40 ℃ : Select 7 groups for measurement 70 ℃ : Select 7 groups for measurement | (°)/h | Take the variance value, data < 1‰ The highest accuracy can reach 0.0005 |
| 8 | Update rate | Hz | >2000 |
| 9 | Zero bias magnetic sensitivity | (°)/h/ Gs | ≤0.003 |
| 10 | Random walk coefficient | (º)/h1/2 | ≤0.0003 |
| 11 | Scale factor nonlinearity | ppm | ≤2 |
| 12 | Scale factor asymmetry | ppm | ≤2 |
| 13 | Scale factor repeatability | ppm | ≤5 |
| 14 | Threshold | (°)/h | ≤0.002 |
| 15 | Resolution | (°)/h | ≤0.002 |
| 16 | bandwidth | Hz | ≥200 |
| 17 | Operating temperature | ℃ | -45 ～ +70 |
| 18 | Storage temperature | ℃ | -55 ～ +85 |
| 19 | Dynamic Range | (°)/s | ±300 |
| 20 | Supply voltage | V | +5 |
| twenty one | Steady-state power consumption at room temperature | W | ≤2.5 |
| twenty two | power consumption at full temperature | W | ≤4 |
| twenty three | Starting instantaneous current | A | <1.5 |
| twenty four | Vibration ( 6.06g ; 20Hz-2000Hz ) | (°)/h | During vibration - ( before vibration + after vibration) /2≤0.1 |
4.1 Mechanical and electrical interface relationship
4.1.1 Power Requirements
The product is powered by a +5V DC power supply. The power supply requirements are shown in Table 2:
Table 2 Power supply requirements for FG-120C fiber optic gyroscope
| Serial number | name | Require |
| 1 | Power supply accuracy | ±5% |
| 2 | Power supply ripple ( Vpp ) | ≤50mV |
| 3 | Supply current | >1.5A |
| Core point number | definition | Notes |
| 1 | +5V | Power Input |
| 2 | GND | Power Ground |
| 3 | reserve | -- |
| 4 | RXD+ | Gyro differential gate positive |
| 5 | TXD+ | Gyro RS422 output positive |
| 6 | +5V | Power Input |
| 7 | GND | Power Ground |
| 8 | RXD- | Gyro differential gate negative |
| 9 | TXD- | Gyro RS422 output negative |
Note: When connecting or touching this product, anti-static measures should be taken in accordance with the provisions of GJB 1649-1993 .
1.1.1 Electrical connection interface
Communication interface: RXD and TXD are both RS422/485 differential communication interfaces. RXD is used to receive differential pulse (or square wave) synchronization selection signals, and TXD is used for serial data signal output.
Communication protocol: After receiving the falling of the strobe signal, the gyro latches the internal angle increment data and starts to output the gyro data packet through TXD within 1μs. The transmission baud rate is 921.6 kbps. The data packet contains 11 bytes, each byte has 1 start bit, 8 data bits, 1 stop bit, and no parity bit.
The angular increment information is the angular increment value of the gyroscope during the time between two selection signals. The accumulated angular increment value during a period of time divided by the interval time is the average angular velocity of the gyroscope during this period of time.
The data packet format is as follows:
Table 4 Gyro data packet format
| Byte sequence number | content |
| 1 | 99 ( hexadecimal ) |
| 2 | 66 ( hexadecimal ) |
| 3 | Status word, normal value is FF ( hexadecimal ) |
| 4 | Gyro angle increment 1 , LSB |
| 5 | Gyro angle increment 2 |
| 6 | Gyro angle increment 3 |
| 7 | Gyro angle increment 4 , MSB |
| 8 | Temperature data, LSB |
| 9 | Temperature data, MSB |
| 10 | Frame number, incremented each time it is sent, cyclic count |
| 11 | Checksum, the sum of bytes 3 to 10 |
| Note: The temperature dimension is 16 . |
The meaning of the status word is as follows:
| bit7 | bit6 | bit5 | bit4 | bit3 | bit2 | bit1 | bit0 |
| reserve | reserve | reserve | Circuit control status | reserve | reserve | reserve | Optical path status |
Among them: "Reserved" bit is always 1;
When the "circuit control status" bit is 1, it means that the gyro circuit control status is normal, and when it is 0, it means that the control status is abnormal;
When the "optical path status" bit is 1, it means that the gyro optical path is working normally. When it is 0, it means that the gyro optical path status is abnormal.
If any of the above two status bits is always 0 during the use of the gyroscope, and is accompanied by abnormal gyroscope data, the gyroscope should be returned for repair.
