DPS 310-S Programmable Servo Controller. DPS Controllers

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1 DPS 310-S Programmable Servo Controller DPS Controllers

2 DPS 310-S Operator s Manual Overview Thank you for selecting Danaher Precision Systems as your positioning equipment supplier. We understand that you can choose from a number of competitive suppliers, and are pleased that you have selected DPS. This manual addresses the DPS 310-S Programmable Servo Motor Controller. As you unpack and begin to use our product, we would like your conclusions as to our products appearance, quality, precision, and suitability to your ultimate application. By providing us with feedback in these and other areas, you can become an active participant in our on-going program of continuous improvement. Our Customer Service department can be reached at: phone: ( in the US) fax: support@neat.com We encourage you to visit our web site at It includes information on new products, along with our existing product catalog, a Motion Control Handbook covering 33 technical topics, and other useful information. Thank you again for choosing Danaher Precision Systems. We look forward to serving you in the future. Contents Set Variations Set Deletions Set Modifications Set Additions Hardware Variations Warranty & Terms Dahaner Precision Systems 7C Raymond Avenue Salem, NH 03079

3 DPS 310-S Controller Operator s Manual Set Variations With few exceptions, the DPS 310-S controller is software and hardware compatible with its companion DPS 310 and 310M Stepping Motor Controllers. The first exception is the most obvious; the 310-S drives either brush type (two terminal) or brushless D.C. servo motors. However, the DPS 310-S drive also differs from our 310 and 310-M models in that a two channel encoder must be present to provide position feedback information, and that position, velocity, and acceleration are entered in units of counts, counts/second, and counts/second2 instead of the corresponding, step-based values. Since the DPS 310-S controller implements a 4x multiplication of encoder line densities, a 500 line/revolution encoder will generate 2,000 counts/revolution. A number of commands, specific to stepping motors, have been deleted and seven new commands, specific to servo motors, have been added. These are detailed below. Set Deletions 1. HS E/D Half Step Enable/Disable Half step mode does not apply to servo motors. 2. IC E/D Idle Current Enable/Disable Because servo motors continuously alter motor current to implement the servo loop, idle current reduction does not apply. 3. VI nn Velocity Initial Stepping motors must begin operation above the primary resonance to avoid missed steps. Servo motors do not exhibit this problem and, hence, begin moves from zero velocity. 4. MI +, c Move to Input Comparator This command was one of two which permitted quasiclosed-loop moves with a stepping motor. Since all DPS 310-S drive moves are fully closed loop, this command has been deleted. 5. RC Report Comparator Omitted; Please see #4, above. Set Modifications 1. JI nn Jog Initial Since the trajectory generator begins moves from zero velocity (please see #3 in Set Deletions), there is no Jog Initial value in that sense. However, home moves consist of a high speed move (set by Jog Final) together with a lower speed final approach to the home switch. The Jog Initial command is retained to allow the low speed home move to be programmed. 2. AC nn ACceleration The trajectory generator in the DPS 310-S drive does not support separate setting of the acceleration and deceleration values. As a result, the AC+ and AC- variants of the ACceleration command are not supported. 3. SP Set Position to Zero The current location of the DPS 310-S drive can be reset to zero via this command. Unlike the DPS 310 and 310-M stepping motor controllers, this command does not accept an argument to allow arbitrary presetting of the position value. 4. RV Report Values Due to the deletion of the Velocity Initial command along with separate acceleration and deceleration values, the Report Values command will return five values: Velocity Final, ACceleration, Jog Initial, Jog Final, and Jog Acceleration. 5. RD Report Defaults Due to the deletion of the Half Step and Idle Current E/D commands, the Report Defaults command will not display these states. A new field called FE nn (Following Error nn) has been added to the Report Defaults returned data. (Please see #2 in Set Additions.) 6. MH 2/4 Move Home, modes 2 and 4 Home modes #2 and #4 are not currently supported by the DPS 310-S controller firmware.

4 Seven new commands, specifically used in servo motor control, have been added to the DPS 310-S controller command set. These are detailed below. 1. SM E/D Servo MotorEnable/Disable This command permits the PID servo loop to be disabled, allowing the motor to be manually rotated without resistance. Once enabled, the servo loop will actively servo the motor at the current location. The encoder counter will track any movements made while the motor was disabled. 2. FE nn Following Error The argument following the FE command is saved and compared with the position error (difference between commanded and actual position). If the difference exceeds the programmed value, the motor will automatically disable the servo loop and an ASCII, E will be issued over the serial port. The programmed value can be saved for subsequent power-ups via the Set Defaults command. The value can also be read via the Report Defaults command. The factory supplied default value is 10,000 counts. This command is useful to prevent motor or amplifier damage for programmed moves which cannot be completed. 3. PT nn Proportional Term This command accepts a 2 byte number nn (0 to 65,535) which determines the proportionality between position error and motor current. Increasing the proportional term will increase the gain, or stiffness, of the servo loop. A typical starting value for the proportional term is 100. Too low a value will result in a large following error while too high a value will result in oscillation. 4. DT nn Derivative Term This command introduces damping into the servo loop by reducing the motor current with a tachometer-like signal proportional to the motor velocity. Too little damping will result in ringing or oscillation, while too much damping results in slower than ideal response to a position change. A typical starting value is IT nn Integral Term This command reduces or eliminates steady state error by preserving a memory of error values during previous sample periods. If a persistent position error exists, the integral term will generate a restoring torque which grows with time, eventually growing large enough to correct the position error. Properly chosen, the integral term will result in zero or one count position error. Too large a value will result in instability. A typical starting value is IL nn Integration Limit This command sets a ceiling above which the integral term (please see #S, above) will stop summing. This will prevent the integral term from reaching inappropriate values should the system (for example) be incapable of reaching its target location. A typical starting value is RT Report Tuning This command returns the programmed values of the Proportional Term, DerivativeTerm, Integral Term, and Integration Limit, in that order. The factory programmed values for these variables are 100, 200, 50, and 200, respectively. New values can be saved for subsequent power-up via the Set Defaults command. Set Additions

5 Hardware Variations The only hardware-specific difference between the DPS 310/310- M drives and the 310-S drive is in the MOTOR connector. The DPS 310-S drives conventional two wire, brush type D.C. servo motors. One terminal is wired to the motor connector pin #1 while the other terminal is connected to pin #6 on the DE-9 connector. While the order with which the motor terminals connect to the MOTOR connector is somewhat arbitrary (connecting them incorrectly will not destroy the amplifier or motor), there is an important and necessary relationship between the motor terminal orientation and the encoder A and B channel phasing. If this relationship is not observed, the system will exhibit positive feedback and the slightest deviation from the original exhibit position will result in full motor output and an uncontrolled, high speed move in one direction. If you purchase a DPS 310-S controller together with a DPS positioning table, our wiring conventions will ensure negative feedback. If, on the other hand, you are using a DPS 310-S controller with another positioning table, or are adding your own encoder, then the following, simple procedure will ensure a proper system relationship: 1. Wire the encoder A and B signals (and A, B, and/or Z, if applicable) together with the supply voltage and ground. Do not wire the D.C. motor. 2. Rotate the motor knob or leadscrew and, using the RP command, determine which direction of rotation (clockwise: CW; or counterclockwise: CCW) corresponds to increasing count (position) values. 3. Briefly connect a low voltage, D.C. power supply (a 9 Volt transistor battery will usually work fine) across the two terminals of the D.C. servo motor. Observe the direction of rotation and reverse the terminal connection, if necessary, so as to generate rotation in the same direction, as previously noted, corresponding to the increasing count direction. The motor terminal which was connected to the battery, or D.C. supply + terminal, should then be wired to the DPS 310-S drive, MOTOR connector pin #1. The other terminal should be wired to MOTOR connector pin #6 on the DE-9 connector. This procedure will ensure that the system exhibits negative feedback and is stable. If, for some reason, the direction of movement which results from + move commands proves to be in an opposite direction from that which is desired, the direction sense can be reversed by interchanging both the A and B encoder signals (as well as A and B, if present) and the motor terminal leads. The DPS 310 and 310-M Stepping Motor Controllers use a pair of user-changeable resistors (located at the front of the main PCB, below the enclosed top cover) to set the main and idle current settings. The DPS 310-S programmable servo motor controller is shipped with a shorting jumper in the main (rear) location and nothing in the idle location. Do not modify these settings. The DPS 310-S drive incorporates two, 24-bit encoder counters. One is used for the primary position servo and can be read via commands such as Report Position and Print Location. The second encoder counter is used solely to generate output strobes at preset locations. The commands Report Encoder andprint Encoder can be used to read this counter, and it may be preset to any value via the Set Encoder command. Home moves will reset the value of this counter to zero. This counter has a 24-bit compare register which can be preset via the Set Comparator command. Whenever the counter value equals the comparator value, a strobe pulse of 200 nanosecond duration is issued on the rear panel, Parallel Port connector at pin #14 (Comparator Output). This output is generated via a hardware comparison without any CPU-based latency (elapsed time between count equality and strobe output is less than one microsecond). Maximum count frequency for this counter is 300 KHz.

6 One final variation between the DPS 310/310-M stepper controllers and the DPS 310-S servo motor controller relates to current requirements. Stepping motors have a fixed current rating; while efficient recirculating drives may reduce the power supply loading at rest, maximum supply current is predictable and does not exceed the capability of the supply. A servo motor, on the other hand, will require a current proportional to the acceleration demands which are made on it. An unrealistically high, commanded value for acceleration can easily exceed the capabilities of the power supply and output FET s. This has two effects: 1. After a short, high current output from the power supply s 10,000 microfarad capacitors, the supply will be incapable of providing the required current. The motor will, accordingly, exhibit increased following error from the commanded trajectory. This could exceed the programmed following error limit and result in the motor being disabled. 2. The power supply capacitors are capable of supplying brief, high currents in response to a high commanded acceleration, which would exceed the limits of the PWM output stage FET s. The DPS 310-S drive has built-in, overcurrent limiting which will prevent FET damage. It functions by inhibiting the output FET s whenever the motor current exceeds 10 amps. The NEAT 310S then attempts to return to normal operation every 8 microseconds until the overcurrent condition disappears. If the FET s exceed 170 C, an additional overtemperature limit inhibits operation until the overtemperature condition disappears. Either, or both, of these effects, if experienced during a high commanded acceleration, can de-stabilize the PID loop and cause oscillations. Accordingly, applications which require high acceleration should be observed cycling back and forth while the acceleration is slowly incremented. Eventual, erratic behavior will be a sign that the commanded acceleration exceeds the capabilities of the power supply or is tripping the overcurrent or overtemperature functions. Hardware Variations, cont.

7 Terms and Conditions Warranty and Terms Danaher Precision Systems (DPS) warrants to original equipment manufacturers, distributors and industrial and commercial users of its products that each new product manufactured or supplied by DPS shall be free from defects in materials and workmanship. DPS s sole obligation under this warranty is limited to furnishing without additional charge a replacement for, or at its option, repairing or issuing credit for any product which shall within one year from the date of sale by DPS be returned freight prepaid to the plant designated by DPS and which upon inspection is determined by DPS to be defective in materials or workmanship. Complete information as to operating conditions must accompany any product returned for inspection. The provisions of this warranty shall not apply to any DPS product which has been subjected to misuse, improper operating conditions or which has been repaired or altered. Seller makes no warranty that its products are fit for the use or purpose to which they may be put by the buyer, whether or not such use or purpose has been disclosed to seller in specifications or drawings previously or subsequently provided seller, and whether or not seller s products are specifically designed and/or manufactured for this purpose. THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING ANY IMPLIED WARRANTY OF MER- CHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. DPS s sole liability on any such claim of any kind, whether in contract, tort or otherwise, for any loss or damage arising out of, connected with, or resulting from the manufacture, sale, delivery or use of the products sold thereunder shall in no case exceed the cost of replacement or repair as provided herein. IN NO EVENT SHALL DPS BE LIABLE FOR ANY SPECIAL, INCI- DENTAL OR CONSEQUENTIAL DAMAGES. There are no other warranties, expressed or implied, made by DPS except the warranty against defects in materials and workmanship set forth above and neither assumes nor authorizes any other person or firm to assume for it any other obligations or liability in connection with its products. Custom design work performed by DPS will be subject to engineering charges. Payments are due upon acceptance of the custom design work. DPS will retain all copyright and other proprietary rights to the product and any additional custom work. The Purchaser shall respect the proprietary rights of DPS and shall take measures to prevent unauthorized disclosure of information relating to the product and any additional custom design work. DPS shall retain all proprietary rights and shall have the right and authority to use, sell, market, research, and utilize for any other purpose at it sole discretion said product and custom design work without notification or any liability whatsoever, including but not limited to monetary remuneration, to the Purchaser. Prices in this quotation do not include any taxes or charges of any nature imposed by any governmental authority which shall become payable by reason of sale, purchase, delivery, storage, processing, use, consumption, or shipment of equipment hereunder. All such taxes or charges shall be the obligation of the buyer and may be either billed to the buyer separately, or added to the price of the equipment shipped. Returning Goods Procedure Shipping/Risk of Loss Field Service Policy Order Cancellation Policy Blanket Order Policy Claims for incorrect or defective materials must be received in writing within thirty (30) days from delivery at buyer s place of business. No units or systems may be returned, in or out of warranty, without first issuing a purchase order and obtaining a return authorization number from the seller, and no claim will be allowed nor credit given for units or systems returned without such approval. Buyer will not be allowed to debit accounts. All credits must be issued by seller. Units which have been exposed to hazardous or toxic materials must be decontaminated at the expense of the Purchaser before being returned. Equipment that has not been decontaminated and certified will not be accepted for repair. After approval from DPS, the defective unit or system is to be Unless express shipping instructions are furnished by buyer, seller will use its discretion. All shipments are F.O.B. seller s If the system or unit cannot be made functional by no-charge telephone assistance or purchased replacement parts, and cannot be returned to the DPS factory for repair, then the following field service policy will apply: DPS will provide an on-site field service representative in a reasonable amount of time, provided that the customer issues a bonafide purchase order to DPS covering all transportation and subsistence costs Any order placed with DPS that has more than one delivery date for the same line item shall be termed a Blanket Order, and is is subject to the following conditions: Specific ship dates must be given for the entire quantity of each item when an order is placed. DPS must receive written confirmation of a purchase order verifying these dates. The entire quantity of each item on an order must be shipped within 12 months of receipt of order. returned to the factory with a written statement of the problem and transportation prepaid. (No C.O.D. or collect freight shipments will be accepted). After DPS s in-plant examination, warranty or out-of-warranty status will be determined. If upon examination of such unit or system, warranted defects exist, then the unit or system will be repaired at no charge and shipped prepaid back to the buyer, via common carrier. If an out-of-warranty situation exists, the buyer shall be notified of the repair cost immediately. At such time, the buyer must issue a purchase order to cover the cost of the repair or authorize the unit or system to be shipped back as is, at the buyer s cost. Warranty work will be suspended when owner/user is in default of financial obligation to seller. plant. Upon delivery to a common carrier, title and all risk of loss or damage in transit shall pass to buyer. and the prevailing cost per hour (eight hour minimum) including travel time necessary to complete the repair, regardless of warranty determination. If the DPS field service representative determines during his on-site repair that the system or unit s problem is not warranty-related, then the prevailing service charge per hour (eight-hour minimum) shall be assessed against the issued purchase order. Cancellation of orders consisting of standard products, for any reason, is subject to a minimum fifteen (15) percent cancellation charge. All standard, non-standard products, custom products, or systems are subject to a cancellation charge to be determined by DPS. DPS reserves the right to refuse any rescheduling of delivery dates. Quantity increases to items on existing orders may not be subject to the same quantity discount as given on the original order. Prices and specifications are subject to change without notice.