Cfm | Elmo DBP SERIES guide

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4.2.1Current feedback, Current feedback multiplier (CFM) and Current loop

Three current feedbacks are obtained by measuring the voltage drop across current sensing resistors or by current transformers (when using the isolation option). These three signals are synthesized and multiplexed which result in a single voltage signal proportional to phases currents. It is then compared to the current command. The error is processed by the current amplifier to provide a voltage command to the PWM section.

Current loop control is obtained by op amp U21/A (current amplifier) and R4, C1 which form a lag-lead network for current loop. The standard amp is equipped with R4 and C1 to get optimum current response for an average motor in this power range. These components are mounted in solderless terminals.

Error amplifier

Current amplifier

x2 Current feedback

CFM

The amplifier is equipped with a Current Feedback Multiplier (CFM). By turning DIP switch 2 (on the upper board of the power stage) to ON, the signal of the current feedback is multiplied by 2 and consequently the following changes occur:

-Current gains are multiplied by 2.

-Current monitor is divided by 2.

-Current limits are divided by 2.

-Dynamic range is improved.

-Commutation ripple is reduced.

DBP - Rev 6/93

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Elmo DBP SERIES manual Cfm

Contents

Rev 6/93 DBP Rev 6/93 ELMO-WARRANTY Performance How to use this manual Flow Chart Table of Contents Step Panel H, DBP1 Description Analog Section Standard Features Type Designation Digital Section Standard Features Technical Specification Digital Outputs Digital I/O specificationGeneral Digital Inputs Digital Outputs Digital Inputs Analog Input Analog input specification Resolver Sensors specificationResolver Option Feature Encoder Encoder Inputs Communication 1 RS232 Configuration2 RS485 Configuration Battery backup Communication Current Control System Operation RS485 and Checksum Protocol CFM Time dependent peak current limit Digital current limits Digital position and speed control Motor Off Mode Position ModeVelocity Mode Servo Mode Input condition Direct commandLatch Mode Program Digit display Hardware signalAuto restart Operation of the shunt regulator Shunt specifications Commutation signals format Short circuit protection Temperature protectionInternal power supply failure Low back-up Battery voltage DBP 3U Block Diagram DCB Block Diagram DCB Components Layout DCB Resolver Option Block Diagram Resolver Board Components Layout Function Terminal Description 20ac,18ac 4ac,2ac8ac 14ac,12acPage Page Control board Reference voltage to the resolver must be Mode 24b ResolverFunction Remarks 24a Auxiliary Encoder Complementary Input Direction Input For Pulse Terminals of DBP Terminals Layout DBP Panel H Mounting Type Double Eurocard Size Type DBP-6U Rack Type Connectors Mother Boards terminals MBA-DBP/3U and MBA-DBP/6U Power Terminals for MBA-DBP/3U Power Terminals for MBA-DBP/6U Circuit common DBP Rev 6/93 Signals connector J3 Signals connector J4 Pin Function Remarks Output J1A, FAN Terminals MBA-DBP/6U only Page MBA DBP/3U MBA-DBP/6U Terminal Function Terminals for DBP mounted in Encd Circuit common DBP Rev 6/93 Signals connector J3 Signals connector J4 Pin Function Remarks Output Page Page MBA-DBP/3UE MBA-DBP/6UE RS232 Communication Port ConnectorRS485 Wiring Installation procedures Mounting Load inductance AC power supply Motors windings Wiring diagrams AC power wiring Ground Guide lines for connecting non-isolated AC suppliesDo not ground AC DBP + I option AC NON-ISOLATED DBP AC DBP Isolating Transformer NON Single Phase Connection AC DBP AC Hall Sensores Connection Hall sensors wiring RS232 Communication 4 RS232 Communication wiring RS 485 Communication 5 RS485 Communication wiring RS485 Communication Differential Encoder Connection Main encoder wiring Resolver Connection Resolver wiring Differential Auxiliary Encoder Connection Auxiliary encoder wiring Input Connection Pulse/Direction signals wiring CFM function Commutation signals formatAbort logic Selecting the communication bus Setting the auxiliary position input formatWhen using an Optical encoder When using Pulse and Direction signals Setting the R/D circuit Setting the main optical encoder formatConverter Oscillator Frequency/Amplitude Selection R228,R233 OscillatorPage OFF Page Page Page Applying Power Applying power Adjustments Defining the amplifier type Adjusting the current limitsEstablishing the communication Checking the feedback elements Self Restart LM0 Latch mode of the protective functionsConnecting the Motor Current limit adjustments Tables and Summaries Display diagnostics Control stage board Poles DIP switch Summary of DIP switches Power stage board Poles DIP switchPoles DIP switch for Resolver Appendix a Current loop response Fig. A-1 Typical current response waveforms DBP Rev 6/93 Appendix B Adding a velocity feedback This page is Blank Appendix C Differential amplifier connection See schematic in chapter Dimensional Drawings DBP1 TOP View 104 111.76 32.3 DBP2 TOP View 107 108 DBP3 TOP View 110 DBP3 Side View DBP4 TOP View DBP4 Side View DBP4 Side View DBP6 TOP View DBP6 Side View 117 DBP6 Side View DBP Rack Mounting 3U/ 13T 119 120 Front Panel for DBP 3U/13T DBP Rack Mounting 3U/20T 122 128.7 101.4123 DBP Rack Mounting 6U/14T Side View DBP Rack Mounting 6U/14T Side View 262 70.92126 DBP Rack Mounting 6U/21T Side View 128 Front Panel for DBP 6U/21T Encd 3U Encd 3U Encd 6U Encd 6U External Shunt Resistor ESR Israel List of Elmo Service Centers Finland