Length measurement of the absolute encoder Application
. One Absolute rotary encoders Mechanical installation:
Absolute rotary encoder mechanical mounting high-speed-side installation, low-end installation, auxiliary mechanical equipment installation and other forms.
 
 

1. High-speed side installation: to the power of the motor shaft end (or geared), the advantage of this method is high resolution, due to the multi-turn encoder has 4096 turns, the motor rotation number within this scale range, can be improved with a full range of fully resolution, drawback is that a moving object through a reduction gear, to return a gear clearance error, generally used for one-way control positioning. Additionally encoder mounted directly on the high-speed side, the motor must be less jitter, or easy to damage the encoder.
2. Low-side installation:
 
After installation in the reduction gear, such as wire rope winch drum shaft or the last section of the reduction gear shaft, this method is no longer gears backlash, measuring more direct, high precision.
In addition, GPMV0814 mechanical rotation number of 90 laps, with this method is more reasonable, if the roll revolutions over 90 laps, can be 1: 3 or 1: 4 gear revolutions adjusted to within the measurement range.
3. Auxiliary machinery installation, machinery installation closing rope:
  Schematic spring tightening rope
1. Pull the rope close
2. Measuring plate
3. Tightening spring Round 1
4. Tightening spring Round 2
5. Special spring
6. Flexible Couplings
7. Encoder
Measuring rope rope close
Cylinder stroke schematic
 
Mechanical spring closing rope from closing rope displacement sensor - flexible steel wire rope connected to a moving object, the rope tight in a dish measuring wheel, rely on constant force spring recovery rope. The encoder is connected to the axle end measuring plate tight, measuring the rotation angle of the rope back and forth movement.
Gravity hammer closing rope:
The weight of the float level measurement schematic
 
1 Encoder
2 Coupling
3 Measuring Wheels
4 hammer to tighten wheel
5 Rope
6 Float
Measuring wheel with constant force spring spring-type similar to, but the recovery force is to rely on another rope pulley coaxial plate hanging hammer to recover.
With the advantages of closing rope displacement measurement is a flexible connection, direct and high precision measurement of moving objects such as environmental vibration, dust, high temperature water vapor occasions can be applied.
Mechanical screw, friction wheel, car axle center rack and pinion connection
 
Installing the encoder in mechanical screw shaft center screw forward a pitch encoder revolution.
By friction wheel with a frictional resistance, friction and rotational relative motion of objects, measure the movement distance.
Note: The friction wheel is always close to the measurement of physical need, and no beating, slip. (Actual use, there are some cases of difficulty)
 
 
By rail car wheel hub mounted rotary encoders, measuring the car travels.
There can not slip between the car and the track
 
Movement was connected to a rack, drive gear equipped with an encoder, the moving distance of the moving object measured
To ensure even closer earthquakes, often with a spring base.

II. Absolute encoder signal output
Absolute encoder signal output has parallel output, serial output, bus output, integrated transmitter output
1. Parallel output:
Absolute encoder output is the number of digital (Gray or pure binary code), parallel output interface that is how high and low output point to represent a digital 1 or 0, the digit is not high absolute encoder usually output directly in this form of digital, direct access to the I / O interface, the output immediate PLC or PC, simple connection. But the parallel output following questions:
1. You must be a Gray code, as in the case of pure binary code, there may be a number of changes in data refresh, reading the wrong code will result in a short time.
2. All interfaces must ensure that the connection is good, because if individual bad connection point that potential is always zero, causing the wrong code can not judge.
3. Transmission distance is not far away, usually twelve meters, the complex environment, preferably with isolation.
4. For more digits, to many-core cables, and to ensure that the connection quality, the resulting engineering difficulties, too, for encoders, to many nodes simultaneously output, increase the failure rate of the encoder damage.

2. Serial SSI output:
Serial output is through the convention, in time there have data output, this convention is called communication protocol, which is connected physical form has RS232, RS422 (TTL), RS485 and so on.
Since the absolute encoder manufacturers are good in Germany, so most of the serial output with the German Siemens
Supporting, such as SSI synchronous serial output.
SSI interface (RS422 mode) to two data lines, two clock line is connected, an interrupt clock pulses to the encoder by the receiving device, the absolute position value is output from the encoder synchronized with the clock pulse to the receiving device.
A trigger clock signal, the encoder output starting from a high level (MSB) and a clock signal synchronized serial signal, SSI standard signal when the signal is not transmitted, the clock and the data bits are high by the receiving device, a first clock signal falling edge, the current value of the encoder begin storing, starting from the rising edge of the clock signal, after the delay time T2, the encoder data signal transmission .t3 starting signal for the recovery, waiting for the next delivery.
 
 
T = 0.9-11us each encoder pulse period is the total number of bits n
t1> 0.45us each half cycle pulse
t2≤0.4us data output delay time
t3 = 12-35us data recovery (off) time
Serial output cable less, transmission distance, the encoder protection and reliability is greatly increased.
General high number of absolute encoder are serial outputs.
3. Fieldbus output
Fieldbus encoders are multiple encoders each with a pair of signal lines are connected together by setting the address, the receiving device transmits signals communications, signal only one interface, you can read more than one encoder signal. Bus RS485 encoder signal follows the physical format, the presentation of its signal called communication protocol, currently the world there are multiple communication protocols have their advantages, yet unified, encoder communication protocol commonly used in the following categories:
PROFIBUS-DP; CAN; DeviceNet; Interbus etc.
Bus encoder saves cable, the receiving device interface, transmission distance, but also can greatly reduce the cost in the case of centralized control of multiple encoders.
4. Integrated transmitter output
   GPMV0814, GPMV1016 absolute encoder provided by the company, which has been in the encoder signal transmitter output directly after the conversion, which has an analog 4-20mA output, RS485 digital output, 14-bit parallel output.
Three. The connection of absolute encoders secondary electrical equipment:
Absolute encoder connected device can be a programmable controller PLC, PC, it can also be a dedicated display signal conversion instrument, and then the output signal from the instrument to the PLC or PC.
1. Direct access to the PLC or PC:
If the parallel encoder output can be directly connected PLC or PC input output contact I / O, its signal mathematical format should be Gray. How many encoders will occupy the PLC how many contacts, if a 24-volt push-pull output, active high 1, low level of 0; if it is an open-collector NPN output, the connection contacts must is NPN type, its active-low, low to 1.
2. If the encoder is serial output, due to communication protocol, followed by electrical equipment must have a corresponding interface.
For example SSI serial, can be connected to the Siemens S7-300 series PLC, there are other special module SM338, or FM451 S7-400 modules, etc., for other brands of PLC, often without specific module or modules are also very expensive.
3. The encoder output bus case, the receiving device to be equipped with a dedicated bus module, such as PROFIBUS-DP.
However, if the select bus output of the encoder, in the middle of the encoder and the receiving device PLC, will not be able to join other display devices, for live shows, it is necessary to give a signal matching signal sub-display meter from the PLC.
RS485 output signal some custom protocols into the PLC's RS485 interface, you need PLC intelligent programming.
4. Connect a dedicated display conversion devices:
For more use of SSI serial output encoder, I provide dedicated display, signal conversion instrument, the instrument for internal decoding, computing, display, signal conversion output, then connect the PLC or PC. Its advantages are as follows:
a. site can have an intuitive display, set parameters directly on the instrument.
b. a special program reading decoding, fault-tolerant, internal calculations, can greatly reduce the amount of programming various projects to improve the stability and reliability. Signal output is calculated directly from the internal digital, fast, and accurate.
c. signal output in many forms, flexible, can be connected to various PLC or later PC, versatility.
Our list of various instruments connected SSI encoder:
GP1312
(C tables, standard tables)
16 parallel code push-pull output, 4-20mA two analog, eight preset position switch,
4 shows a nonlinear conversion, common functions such as panel set
GP1312 / C2
(C2 table,
Dual correction table)
Synchronous rectification type twin-lift, 16 push-pull parallel code strobe output, nine preset switch output, including dual ultra partial correction signals, two 4-20mA analog outputs, one for the difference between the amount of output.
Dual 4 shows a nonlinear conversion, common functions such as panel set
GP1312RL
(RL table,
Live transmission table)
One 4-20mA analog output; all the way RS485 output. Non-linear conversion, external set, etc.
GP1312BS
(BS table, electronic cam switch group)
Eight electronic cam position switches, each having an open place and in the recovery position,
One 4-20mA analog output; all the way RS485 output.
4 shows a nonlinear conversion, external set, etc.

GPMV0814, GPMV1016 Trinity type
GPMV0814 absolute multi-turn encoder photoelectric encoder reading decoding, display settings, signal conversion trinity, output 4-20mA analog, parallel digital output RS485 communication can simultaneously connect various types of PLC and PC.
General application, while the optional two-output, a set of signals to connect PLC, another group of connected display devices, such as the need to increase the switching output can be set from the display instrument output.