Guangdong GDXH digital readouts Co., Ltd

Shenzhen Baoxin Electronic Co., Ltd.

Linear Encoders MK Series Manuals

Closed linear grating scale



Directory ……………………………………  

 General Description …………………………………………   

Operating Guideline ……………………………    

Safety Considerations ………………………………   

1. Technical Parameters …………………………………   1

2. Encoder Structure  ………………………………………  3

3. Optional Parts  ……………………………………………   4  

4. Installation …………………………………………………   5

4.1 Installation Dimension  ………………………………     7

4.2 Principle of installation  ……………………………    10

4.3 Installation of Encoder and Enclosure ……………… 11

4.4 Installation of Reading Head …………………………  13

4.5 Switchover of Reading Head Cable ……………  14

   5. Acceptance Rules ………………………………………… 15

General Description

Many thanks for your use of this series of encoder. It is China’s most famous international brand. It will be your best bet once you choose it. We are a professional factory dedicated to manufacture of encoder numerical display. By continuous modification and improvement through years of research and production, we have developed today’s MK series linear encoder. The MK series encoder under this manual includes MK-300, MK-600, MK-500. which can meet the requirements in different applications.

MK-300 is a type of encoder with wide applications. It features optimal structure, good appearance, and high rigidity, able to meet the needs of the majority of general machine users. The length is 70~1020mm.

MK-600 encoder, which is specifically designed for large machine tool, features in large size and good rigidity. Support may be added to any position of the encoder to enhance the rigidity and stability. The length is 1000~3000mm.

MK-500 is a mini-encoder specially designed for the machine tool which has a low installation size and small operation space. It can meet the needs of those customers who have requirements for position. The length is 70~470mm.

Operating Guideline

  • Before use, the user must read the General Description, Safety  Considerations and all the contents in Chapter1~3.
  • Except the General Description, Safety Considerations and all  the contents in Chapter 1~3, the technicians for installation,  testing and repair must thoroughly understand all the contents in Chapter 4~5.
  • This Operating Instructions is only applicable to GDXH’s MK series integrated linear encoder.
  • Please read the Safety Considerations below. It is critical information related to safe use of your linear encoder.

Safety Considerations


  • To avoid electric shock or fire, the equipment connected to the encoder shall be kept from moisture or direct contact with cooling liquids.
  • Encoder is a precision measuring instrument. To ensure its normal  function, never expose it to external shock or vibration.


  • To prevent mal-alignment of encoder and avoid electric shock, never open any seal on encoder. There is no part that needs the user’s repair. Please ask the authorized technicians to repair.

Notes :

  • If finding any smoke or smell from the reading head, please immediately cut off the power supply. As the encoder connects with the numerical display to form a precision measuring instrument, continued use in event of the above phenomena might cause fire or an electric shock to the numerical display. Please contact GUANGDONG GDXH DIGITAL READOUTS Co., Ltd. or its dealer. Never try to repair by yourself.
  • Once the wire between the numerical display and encoder is broken or damaged during use, it will cause an error to the test data. The user shall take special care of this.
  • Never try to repair or refit the scale, as it might cause failure, trouble, or damage.

CE The displacement sensor complies with the 2006/95/EC directive for low-voltage electric apparatus and the 2004/108/EC directive for EMC.

      In light of the principle focused on easy installation, use and maintenance by the user, GUANGDONG GDXH DIGITAL READOUTS Co.,Ltd. has developed MK series linear encoder based on the condition of optimized structure and guaranteed precision. With a precision conforming to standard, this product features in good rigidity, straightness, sealing and appearance. The accessories and spare parts are easy to install and repair, resulting in largely reduced installation labors. Please read the following chapters thoroughly, so that you may use this device more easily.

1.1Technical Parameter

1.1 Scaling distance: 0.02 mm (50lines /mm)

1.2 Resolution: 5µm、1µm、0.5µm

1.3 Precision: ±3µm、±5µm、±15µm/m(20±0.1℃)

1.4 Measuring range: 70~3000mm

1.5 Moving speed: High-speed encoder 120 m/min(To be customized)  Ordinary encoder 60m/min

1.6 Power supply: +5V±5%、80mA

1.7 Cable length: Standard 3m (Special length available according to the user’s needs)1

1.8 Working Temperature:   0~45℃

1.9 Pin Description:      

  1. ) Applicable to:9 pin socket RS-422 signal Output.

2.)Encoder Structure:

The encoder mainly consists of scaling body and reading head, as shown in Fig.1:

Fig. 1

  1. Scaling body   2. Cable   3. Read head   4. Connection plate fixing the reading head

3.3. Optional Parts

To install and use the encoder normally under different conditions, we have designed the following spare parts:

  • 4. Installation

4.1 Installation Dimension

Overall Dimension of MK-300 Encoder


L0: Effective measuring length of encoder L1: Dimension of encoder mounting hole L2: Encoder overall dimension

Overall Dimension of MK-600 Encoder

Fig.17L0: Effective measuring length of encoder L1: Dimension of encoder mounting hole L2: Encoder overall dimension

Overall Dimension of MK500 Encoder


L0: Effective measuring length of encoder L1: Dimension of encoder mounting hole L2: Encoder overall dimension


(1) Select the measuring range of encoder according to the travel of machine tool. The measuring range of encoder must be higher than the maximum travel of the machine tool.

(2)Select proper parts according to the length and mounting plane provided.

(3)The hanging plate needed for MK-600 encoder shall be arranged

Every 1000mm, respectively 2 hanging plates if 1000L<2000; 3 plates if 2000L<3000; and 4 plates if L=3000.

4.2  Principle of Installation:

  • The encoder must be installed with the guide rail of machine tool as the benchmark and be kept in parallel. The center of encoder measuring range must be positioned on the center of travel of machine tool. Ensure that the actual measuring range of encoder is higher than the maximum travel of machine tool.
  • The installation shall be based on priority principle as such that the encoder shall be installed close to the drive screw of machine tool. After installation, the body of encoder moves with the work bench, while the reading head is fixed on the machine tool.
  • The encoder shall be so installed that it will not obstacle the operation or reduce the function of machine tool.
  • After installation, the encoder shall be kept from knock. During machining, it shall not obstacle the handle of machine tool or affect the brake or other protrusions. It is not easy to contact when a workpiece drops.
  • The encoder shall be vertically installed, as shown in Fig.19. But wherever impermissible, horizontal installation is also acceptable. Never install theencoder upside down (that is, reading head on top and encoder body at lower). Never direct the rubber seal of encoder toward the outlet of cooling oil from machine tool.

                              Fig 19

  • The encoder enclosure shall be securely earthed to ensure the signal integrity.
  • The parallelism and verticality between encoder and guide rail of machine tool shall be within 0.10 mm/m.

4.3 Installation of Encoder and its Enclosure

  • Installation of MK-300C Enclosure Encoder

  A. Select proper installation position;

  B. Mark line on the mounting plane according to the length of installation, and drill M4 mounting hole.

  C. Install the encoder onto mounting plane. Use the dial gauge to check the parallelism between encoder and guide rail of machine tool, and adjust it to beststate. (See Fig. 20)

  D. Fix the encoder onto mounting plane.

   E. Adjust the screw fixing the reading head, making it slightly touch the mounting plane.

 F:Drill M4 screw hole according to the mounting hole

on reading head.                                            Fig .20

 G. Fix the reading head and remove the connection plate.

 H. Drill M4 screw hole according to the mounting hole on encoder enclosure.

 I. Fix the ncoder onto mounting plane.

(2)Installation of D, X & H Enclosure  Encoder 

4.4 Installation of Reading Head

The reading head may be positively or reversely installed on the machined or non-machined plane. Generally, positive installation is used. The reverse installation is used only when the installation space is not enough and it is not easy to  install positively.

  • Positive Installation of Reading Head

Shown in Fig. 23 is positive installation of reading head. During installation, take care

that the encoder plane shall be kept parallel to the reading head plane and that their sectional centers shall be kept consistent, with an error within 0.10mm.

  • Reverse Installation of Reading Head

Shown in Fig. 24 is reverse installation of reading head. The installation steps are as follows:

  1. Install T-frame (optional) onto machine tool.
  2. Remove the connection plate fixing the reading head.
  3. Adjust the tightening screw on T-frame mounting plate, making it slightly touch the reading head.
  4. Use front and rear M5 screw to fix the reading head onto mounting plate of T-frame.
  5. Adjust  the  position  of  T-frame  plates,  making  the  reading  head  in  a  relative position to the encoder as shown in Fig. 24.
  6. Install the encoder by using T-frame.

4.5 Switchover of Reading Head Cable (Applicable to MK-300, MK-500 and MK-600)

Upon shipment, left or right outlet is available for the reading head cable according to different specifications. You may change the direction of the cable if needed. The steps are as follows:

  • Loosen and remove 4 cross-head screws M2 fixing the reading head cover and 2 adjusting screws M3 on the right side of reading head.
  • Put 2 socket hexagonal screws M4 into the adjusting screw hole and screw forward respectively to prop up the cover plate. When there is a clearance, use screwdriver to prize up the cover plate along the edge of reading head.
  • Loosen 2 slotted-head screws M3 fixing the cable on the bottom of reading head. Remove the cable and terminal. Change the direction.
  • Before reinstalling the cover plate, remove the original sealing glue before applying new sealing glue.
  • Remove socket hexagonal screw M4. Reinstall the cover plate and tighten 4 cross-head screws M2.

Note: To avoid slippery of screw head, please use correct tools in each step.

5.Acceptance Rules

  • The connection of reading head shall have adequate rigidity. Shaking with force and observing the numerical display, the value shown on it will have some deviation. If releasing your hand, the value on numerical display shall be able to resume to original value.
    • The reading head shall located at the center of encoder, so that the sealing strip may close or open symmetrically, as shown.
    • The connecting plate may guarantee the position of reading head in encoder center and its relative position to encoder body.
    • The position of reading head relative to encoder and its mounting dimension are shown below.
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