Absolute Rotary Encoder with Profibus-DP-Interface DPC1B version User Manual
1 5.1.2 Desired measuring units ........................18 5.1.3 Desired Measuring units reference ........19 General ............................................................ 3 1.1 Absolute Rotary Encoder............................... 3 5.1.4 Activate commissioning mode ...............20 5.1.5 Shorter Diagnostics ...............................20 5.1.6 Software-limit switch ..............................20 5.1.7 Physical impulses ..................................21 1.2 Profibus technology ........
8.3 Mechanical Data .......................................... 38 10.2 Further encoder configurations ..................43 10.2.1 Version 2.0 Multiturn...........................43 10.2.2 Version 1.1 Multiturn...........................43 10.2.3 Version 1.0 Multiturn...........................43 10.2.4 Class 2 Multiturn ‚DX-Version’ .............43 8.4 Environmental Conditions ............................ 38 10.3 FAQ absolute encoder Profibus .................44 Dimensioned Drawings.....................
shaft position over up to 16384 revolutions (14 bits). The position value is calculated in an integrated microprocessor and transmitted over the Profibus. 1.2 Profibus technology PROFIBUS is an international, open, nonproprietary fieldbus standard which is defined in the international standards EN 50170 and EN 50254. There are three different versions: Profibus DP, Profibus-FMS and Profibus-PA. absolute encoders are designed for the DP version. They support all usual baud rates up to 12 MBaud.
2 Installation The Absolute Encoder is connected with a connection cap. This cap is connected to the encoder with a 15-pin-D-Sub connector and can be removed by loosening two screws on the backside of the encoder. Bus lines and power supply are led into the cap via cable glands and connected to terminal blocks. 2.1 Settings in the connection cap 2.1.1 Station address 2.1.2 Bus termination The station (node) address is set by using the rotary switches in the cap.
2.2 Connecting bus lines and power supply B A + B A + R ON Clamp Description B (left) Bus line B (Bus in) A (left) Bus line A (Bus in) - 0V + 10 – 30 V B (right) Bus line B (Bus out) A (right) Bus line A (Bus out) - 0V + 10 – 30 V B A + B A + The power supply has to be connected once (no matter which clamps). If the terminating resistor is switched on, the outgoing bus lines are disconnected. 2.
2.
2.5 Connecting the screen To achieve the highest possible noise immunity shielded cables should be used for data transmission. The shield should be connected to ground on both ends of the cable. In certain cases, a compensation current might flow over the shield. Therefore a potential compensation cable is recommended. 2.
3 Device Configuration The Absolute Encoder with Profibus-Interface can be programmed according to the needs of the user. The GSD-file has to be installed in the used software tool. The user has the possibility to choose different encoder configurations. Parameters and functionality depend on the selected encoder configuration. -Absolute Encoders Type „MHM5-MHK5-DPC1B-XXXXXXXX-0CC“ support all configurations described in the following, i.e. there is no functionality limitation due to the hardware.
3.
3.3 Encoder configurations - data format Designation Configuration Input words Hex Dec. (Encoder -> Master) Output words (Master -> Encoder) Class 1 Singleturn (According to Profile) D0 208 1 0 Class 1 Multiturn (According to Profile) D1 209 2 0 Class 2 Singleturn (According to Profile) F0 240 1 1 Class 2 Multiturn (According to Profile) F1 241 2 2 2.1 Singleturn F1 241 2 2 2.1 Multiturn F1 241 2 2 2.2 Singleturn F1 D0 241 208 2 1 2 2.
4 Class 1 and Class 2 profile The encoder versions Class 1 and Class 2 are defined by the working group encoder in the „Profibus Nutzerorganisation“ in the “Profile for Encoders” (available from the PNO, Order No. 3.062). 4.1 Parameter settings The following table contains an overview of the parameters according to the Profile for Encoders and the structure of the parameter telegram.
4.1.1 Code sequence The parameter „code sequence“ defines the counting direction of the position value. The code increases when the shaft is rotating clockwise (CW) or counter-clockwise (CCW) (view onto the shaft). The code sequence is defined in bit 0 of octet 9: Octet 9 Bit 0 Direction of rotation when viewing the shaft Code 0 Clockwise (CW) Increasing 1 Counter-clockwise (CCW) In Class 1 this is the only parameter that can be set. Increasing 4.1.
4.1.6 Total measuring range Octet 14 15 16 17 Bit 31 – 24 23 – 16 15 - 8 7-0 Data 231 to 224 223 to 216 215 to 28 27 to 20 Programmed total measuring range in steps The parameter „total measuring range“ is used to adapt the measuring range of the encoder to the real measuring range of the application. The encoder counts up until the position value has reached the programmed total resolution and starts with 0 again.
For multiturn devices with 16384 revolution the rule is as follows (if it is necessary to turn the encoder shaft more than 4096 revolutions without power supply): The period, i.e. “Total resolution” / “measuring units” per revolution must be an integer and it must fit an integer number of times (integer multiple) into 16384. So the following equation must apply: (16384 x measuring units per revolution) / Total resolution = integer 4.
Data bits Bit Master 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 → 1 0 Transfer of the required position value (= preset value) → 0 0 New = required position value is transferred → 0 0 Reset bit 31 – normal mode → 0 0 New = required position value is transferred 13 12 11 10 9 8 7 6 5 4 3 2 1 0 MHM5 MHM5 Master Master MHM5 MHM5 Master If high precision is required the preset function should only be executed if the encoder shaft is not moving.
5 Special versions 2.1 and 2.2 The manufacturer-specific encoder configurations 2.1 and 2.2 offer (in addition to the functions according to the Profile for Encoders) features such as commissioning mode, velocity output and software limit switches. Octet (byte) The following table gives an overview of the used parameters and the structure of the parameter telegram. Usually it is not necessary to know these details as the parameters are set with user-friendly software tools. Parameter Details No.
5.1 Parameter In the following the manufacturer specific parameters are described in detail. The parameters according to the Profile for Encoders are supported too, description: see chapter 4. 5.1.1 Activate manufacturer-specific parameters The manufacturer-specific parameter byte 26 is activated with bit 6 in octet 9. Bit 7 in octet 26 activates further parameter bytes (27-39). Usually this happens automatically if the encoder versions 2.1 or 2.2 are selected.
5.1.3 Desired Measuring units reference With this parameter the reference for the desired measuring units (cp. 5.1.2) is determined, either per revolution per maximum total resolution per number of physical impulses Desired measuring units per revolution In this case the position value increases by the programmed number of steps (desired measuring units) over one revolution. Additionally the parameter “total resolution” is used to achieve an adaptation of the measuring range (cp. 4.1.6).
5.1.4 Activate commissioning mode Bit 2 in octet 26 activates the commissioning mode. This is a special mode with the option to set further parameters in the data-exchange –mode (additional to the preset value). In the commissioning mode a „Teach-In“ can be carried out, i.e. the gearing factor can be determined directly in the machine. In this special mode (indicated by the flashing green LED) the parameters set in the system configuration are ignored by the encoder.
Octet 31 32 33 Bit 31 - 24 23 - 16 15 – 8 31 Data 2 24 23 to 2 2 16 15 to 2 2 34 7-0 8 27 to 20 to 2 Upper limit switch (in measuring steps, related to the scaled value) Octet 26 Bit 5 Lower limit switch 0 Deactivated 1 Activated Octet 26 Bit 6 Upper limit switch 0 Deactivated 1 Activated 5.1.
4096 steps/revolution x 3 revolutions = 12288 steps Enter this value (12288) as „physical impulses“ and set the „desired measuring units“ to 400. Now the encoder increases the position value by 400 steps on a measuring range of 12288 physical steps (3 revolutions). Note: With many software tools it is necessary to divide the value into high and low word, refer to page 35. 5.1.8 Encoder type The encoder type (Singleturn or Multiturn) is specified in bit 1 octet 39.
5.2 Data exchange in normal operation With the manufacturer-specific versions 2.1 and 2.2 the process value generally is transmitted as 32-bit-value (peripheral double word). Apart from 25 bits used for the position value the 7 other bits are used as status bits. The output double word contains the preset value and control bits. Absolute encoders model series “MHM5” might have (physical) position values > 25 Bit.
5.3 Commissioning mode If the commissioning mode is activated in the encoder parameters, the scaling factor can be determined directly in the machine by a „Teach-In“. The commissioning mode is indicated by the flashing green LED and bit 26 in the input double word (bit 26 set to 0). If the encoder starts up in commissioning mode the parameters in the system configuration (code sequence, scaling) are ignored. Parameters stored in an internal EEPROM are used instead.
5.3.2 Teach-In Start After the machine / system has been moved to the start-position the Teach-In-Start command is Status bits Master transmitted to the encoder. The device now starts the internal calculation of a new scaling factor.
measuring range“. When setting the parameters it should be observed that the code sequence is correct (the setting of the counting direction in commissioning mode has to be transferred to the system configuration). Subsequently the commissioning mode can be switched off and the encoder can be used in normal mode. In order to replace the encoder later without a new Teach-In procedure, the total measuring range determined with the Teach-In should be transferred into the system configuration.
6 Diagnostic messages 6.1 Overview On request of the master the encoder transmits diagnostic data ("DDLM_Slave_Diag"). The diagnostic data length is 57 bytes (Exception: shorter diagnostics, cp. 5.1.5). The format of the diagnostic data is according to the Profibus Standard (octets 1-6) respectively according to the Profile for Encoders (starting from octet 7). Diagnostic function Data type Diagnostics - octet number Class Station status 1 (ref.
6.2 Supported diagnostic messages 6.2.5 Singleturn resolution In the following the different diagnostic messages are described in detail. Diagnostic bytes 11-14 contain the real (physical) resolution per revolution of the encoder. 6.2.1 Extended diagnostics header 6.2.6 Number of revolutions Byte 7 contains the length of the extended diagnostics (including header itself). Diagnostic bytes 15 and 16 contain the real (physical) number of revolutions of the encoder.
6.2.11 Zero offset 6.2.14 Serial number The zero offset is output in diagnostic bytes 32 to 35. Diagnostic bytes 48-57 are intended for a serial number. With the current version the serial number is not saved in the encoder, the bytes contain the default value 2A hex. 6.2.12 Programmed resolution The programmed resolution per revolution is output in diagnostic bytes 40 to 43. The value is only valid if the scaling factor is based on the parameter „resolution per revolution“ (cp. 5.1.3). 6.2.
6.3 Status indication by the LEDs in the connection cap Two LEDs are implemented in the connection cap. They optically indicate the status of the encoder in the profibus network. The red LED is used to display errors, the green one displays the status of the encoder. Both LEDs can have one of three possible conditions: dark, bright and flashing. Seven of the nine possible combinations are used to indicate a special condition.
7 Configuring with STEP 7 In the following the configuration of the encoder with the configuration tool STEP 7 is shown exemplarily. In this example STEP 7 Version 5.1 and the CPU 315-2DP (profibus-master integrated) are used. If there are questions about other software tools please contact the manufacturer. 7.1 Installing the GSD file If encoders are used for the first time it is necessary to install the GSD file („FRAB4711.
7.2 Configuring the encoder After inserting the Profibus master system in the hardware configuration (“Insert” – “Master System”) the encoder can be chosen from the hardware catalogue and added to the profibus network: Select the device “ Encoder” and drag it with the mouse to the network (or choose the network and double click the “ encoder”). Now the slave address has to be entered (has to be equal to the address setting in the connection cap).
7.3 Selecting the encoder version As described in chapter 3 the functionality of the encoder depends on the selected encoder version. After the “ encoder” has been added to the network the desired encoder version can be selected. For Revision 03/10 this, one of the modules listed under encoder has to be dragged to Slot 1 in the displayed configuration table of the encoder.
7.4 Setting the parameters Select the encoder in the hardware configuration and double click slot one in the configuration table of the encoder. The dialog „Properties – DP slave“ appears. The input and output addresses can be changed (if desired). To set the encoder parameters the tab “Parameter Assignment” has to be selected. After choosing the „Device-specific parameters“ the different parameters (depend on the encoder version) can be set.
Due to the old versions of software tool STEP7 32-bit parameter values (e.g. total measuring range, software limit switches) have to be divided into high and low word. This is not necessary with the new STEP7 versions and our actual GSD file.
Page 36 BEI Sensors Profibus Manual serie M Revision 03/10
8 Technical Data 8.1 Electrical Data General design According to DIN VDE 0160 Protective Class III, degree of pollution 2, over voltage Category II Power supply voltage 10 - 30 V DC (absolute limit values) * Power drain max. 2.5 Watt Current consumption max. 230 mA with 10 V DC, max.
8.3 Mechanical Data Housing Aluminum, optional stainless steel Lifetime Dependent on shaft version and shaft loading – refer to table Max. shaft loading Axial 40 N, radial 110 N Inertia of rotor 30 gcm2 Friction torque 3 Ncm / 5 Ncm (without / with shaft sealing) RPM (continuous operation) Singleturn: max. 12,000 RPM Multiturn: max.
9 Dimensioned Drawings Synchro flange (S) available in 2 versions Synchro flange d / mm l / mm Version S06 6 f6 10 Version S10 10 h8 20 Clamp flange (C) Revision 03/10 BEI Sensors Profibus Manual serie M Page 39
Hollow shaft (B) Mounting instructions The clamp ring may only be tightened if the shaft of the driving element is in the hollow shaft. The diameter of the hollow shaft can be reduced to 12mm, 10 mm or 8 mm by using an adapter (this reducing adapter can be pushed into the hollow shaft). Page 40 Allowed shaft movements of the drive element are listed in the table. axial radial static ± 0.3 mm ± 0.5 mm dynamic ± 0.1 mm ± 0.
10 Appendix 10.1 Type designation / ordering code Description Interface Version Code Revolutions (Bits) Steps per revolution (Bits) Flange / Shaft Diameter Mechanical options Connection Type Key MHM5 MHK5 DP Profibus DP C1 B- __ __- ___ _- ___ C1 Binary Singleturn Multiturn (4,096 revolutions) B 00 12 Multiturn (16,384 revolutions) 14 4,096 (0.09°) 12 8,192 (0.04°) 13 65,536 (0.
Accessories and Documentation Description Article name Article number Aluminium housing with 3x M12 cable glands for cable diameters between 6,5 – 9 mm AH 58-B1DP-3PG 0246370340 Stainless steel housing with 3x M12 cable glands for cable diameters between 6,5 – 9 mm AH 58-B1DP-3PG-VA 0246370355 AH58-B1DP-072 0246370359 AH 58-B1DP-2M20 0246370344 Shaft coupling ** Drilling: 10 mm / 10 mm Drilling: 6 mm / 6 mm GS 10 GS 06 29100450 29100350 Clamp disc ** 4 pcs / encoder SP 15 32400155 Clamp h
10.2 Further encoder configurations The encoder versions described in the following are still supported for reasons of downward compatibility. They should not be used in new projects! 10.2.1 Version 2.0 Multiturn This version differs from version 2.2 in the fact that there is a smaller number of parameters shown in the configuration tool. 10.2.2 Version 1.1 Multiturn This is an older version formerly called Class „3“. It is similar to class 2 but has an additional velocity output.
10.3 FAQ absolute encoder Profibus Problem There are problems with the profibus network (bus error, no answer from the encoder) if one of the following profibus masters is used: - SIEMENS S5-95U Master Interface SIEMENS IM 308-B Softing PROFIboard Allen Bradley 1785 PFB/B Mitsubishi A1SJ 71PB92D Solution If it is possible the maximum number of diagnostic data per slave should be increased in the master.
Problem Sporadic bus errors The resistance value must be about 110 Ω (220 Ω parallel 220 Ω). Possible cause Terminating resistors not correct Possible cause EMC problems Possible solution Check terminating resistors! The resistors of 220 Ω must be switched on at the beginning and at the end of the bus segment. Switch off the power supply and measure the resistance between the terminals A and B in the connection cap.
GSD file File that contains slave-specific characteristics. The GSD file is supplied by the manufacturer of the profibus slave. The GSD format is standardized (defined in GSD specifications), so configuration tools of various manufacturers can use the GSD files. Master “Active” device in the network that can send data without request. Controls the data interchange.
11 Index B L Bus termination ................................................. 5 LEDs................................................................30 Low word .........................................................35 C Class 1............................................................ 12 Class 2............................................................ 12 Code sequence............................................... 13 Commissioning mode .....................................
12 Revision index Revision Date Revision Changed to new type key DPC, new technical drawings, new connection cap 9.4.2010 03/10 4.
