Drive Information
Drive functions include absolute and incremental moves, clockwise (CW) and
counter-clockwise (CCW) jogging in both a high and low speed, a home
function with limit switch, making X number of steps at F velocity,
reading complex data instructions through thumbwheels, PLC communication and
several others.
It can drive its stepper motor in a number of modes: supplying power to the motor at all times when a holding torque at stand-still is needed; supplying power to the motor only when in motion (all windings off) when no torque is needed at stop or when motor heating is a concern; increasing the current during motion to increase acceleration and torque; or, with reduced current for better efficiency when full power is not necessary. In a free standing, no load demonstration application, these modes will have little effect on motor performance except for motor temperature.
Like most motor drives, the 3180 EPI produces lethal voltages. Care must be taken to avoid contact with motor or drive while power is supplied, and proper grounding procedures must be used. The drive contains a number of capacitors which store dangerous voltages after the drive has been turned off. Wait five minutes after shutting off power before making any connection changes or handling the drive.
RS-232 Connections
The 3180 EPI drive is not programmed so much as it is wired.
Although the 3180 EPI drive can be further programmed with additional
information and parameters, most commands can be given through switches
and thumbwheels. In fact, this drive can be operated right
out of the box without ever being connected to a computer.
The drive is connected to the controlling switches and thumbwheels by a 25 pin parallel connection located next to the 9 pin port. (See Appendix) This includes 7 outputs for PLC communication, 8 inputs and 8 outputs for switch and thumbwheel connections (which includes 2-4 programmable inputs).&nBy connecting the 8 outputs (or Strobe 0-7) to the 8 inputs (or Data 0-7) in various combinations, the drive can be run, given data and even programmed.&nStrobes 2-7 are dedicated to be used with thumbwheels for data collection.&nStrobes 0 and 1 are used for limit switches, cycle start and stop switches, jog control, programmable inputs, data-load and other drive controls.
During normal operation, only Strobe 0 and Strobe 1 are activated - the data fields are ignored and any changes to the thumbwheels or selector switches will be ignored. When the Load switch is actuated (Strobe 1 is connected to Data 2), Strobes 0 & 1 are deactivated and Strobes 2-7 are activated. The data from the thumbwheels is read and processed. Strobes 0 & 1 are re-activated and Strobes 2-7 are turned off again.
Information is taken from the thumbwheels in Binary Coded Decimal (BCD) format. Pin connections are assigned values 1, 2, 4, 8, 10, 20, 40, 80 through 80,000,000.
For example, if Strobe 7 were connected to Data 1, 2 & 7, Strobe 6 were connected to Data 0 & 3, and Strobes 4 & 5 were connected to no Data pins, the drive would read a value of 986. (see appendix). These connections are made inside the thumbwheel hardware. Example #2, if the ones digit read 6, it would connect Strobe 7 to Data 1 & 2.
There are two sets of data fields: Strobes 4-7 can read values from 0 to 99,999,999, which is recorded and a numeric value - for example, the number of steps to be taken; Strobes 3 & 4 can read values from 0 to 999 which activate commands, line numbers in a program, or set parameters and speeds.
The meaning of the data fields is determined by the selector toggle switches
connected to Strobe 4 and Data 5-7. Eight combinations are
possible (2^2) which allows the code Strobes (3&4) and the value Data
(5-7) to be read as:
0 Line Number to be executed 4 L Command which sets parametersMany G Commands, H commands and Strobe 0 & 1 commands are redundant. For further information about L, G, H commands and default settings, see Appendix in Superior Drive Manual.
1 G Command to be executed 5 H command to be executed
2 Distance or number of steps 6 Return to default settings
3 Velocity 7 not used
By wiring the drive to one or two thumbwheels and an number of switches or relay contacts, the drive can be run, jogged, programmed and adjusted to meet changes in application. Not all pins need be wired. This drive was originally set up to be run with only one thumbwheel for data values and a few switches.
Applications
An open loop stepper motor can be used in a great number of applications and
has the advantage of being cheaper than a full servo system.
Their best use is in simple intermittent motion or when precise steps
are needed. Such applications may be advancing a printer one
line at a time, twisting a wire a determined number of turns, some
intermittent motion conveyor applications, laser or pen positioning and
table movement.
The Strobe and Data pins can be connected in variety of ways, suited to each application. The easiest way to enter numeric data is either through thumbwheels or through a computer terminal. The remainder of the connections could be controlled by push-buttons, selector switches, toggle switches, limit switches, relay contacts (which could be energized by a PLC or hard-wired logic) or a combination of these.&nThe Cycle Start command could be wired to a push-button switch that an operator would activate as well as a set of relay contacts which may be energized by a PLC.&nSome other connections may not be used at all, depending on the application.
Appendix Strobe 0 Strobe 1 Pin# Assignment 1 Signal Common Vo Data 0 CW Limit CW Jog 2 Data 7 Input Data 1 CCW Limit CCW Jog 3 Data 5 Input Data 2 Home Limit Data Load 4 Data 3 Input Data 3 Clear Cycle All Windings Off 5 Data 1 Input Data 4 Pause High/Low Speed 6 Motion Busy Output Data 5 Input #1 Enable Jog 7 Strobe 7 Output Data 6 Input #2 Cycle Start 8 Strobe 5 Output Data 7 Stop Cycle 9/25 Pin Connection 9 Strobe 3 Output 10 Strobe 1 Output 11 Output #2 12 All Windings Off Output 13 CW/CCW Output 14 Signal Common Vo 15 Data 6 Input 16 Data 4 Input 17 Data 2 Input 18 Data 0 Input 19 Position Error Output 20 Strobe 6 Output 21 Strobe 4 Output 22 Strobe 2 Output 23 Strobe 0 Output 24 Output #1 25 Pulse Output Strobe2 Strobe3 Strobe4 Strobe5 Strobe6 Strobe7 Data 0 1 100 1M 10k 100 1 Data 1 2 200 2M 20k 200 2 Data 2 4 400 4M 40k 400 4 Data 3 8 800 8M 80k 800 8 Data 4 10 +/- 10M 100k 1k 10 Data 5 20 Sel 1 20M 200k 2k 20 Data 6 40 Sel 2 40M 400k 4k 40 Data 7 80 Sel 4 80M 800k 8k 80 Code Data Value Data Example: Connecting Strobe 7 to Data 1, 2 & 7 yields 2 + 4 + 80 = 86 Connecting Strobe 6 to Data 0 & 3 yields 100 + 800 = 900 Connecting Strobes 4 & 5 to no Data pins yields 0 86 + 900 + 0 =986 Example: Connecting Strobe 2 to Data 0, 3, 4, 5 yields 1 + 8 + 10 + 20 = 39 Connecting Strobe 3 to Data 5 & 7 yields (Sel 1) + (Sel 4) = Select 5 = H code H Code 39 Enables Reduce Current Mode By setting the Data Value Thumbwheel to 986, the Code Data Value to 39 and the Selector Toggle switches Up, Down, Up these connections are made within the hardware.
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For more complex sequences, the drive can be programmed with Slo-Syn DOS
based software through a RS-323 communication cable.
The information provided both in the software help files and the drive
manuals for the computer connections is incorrect. The
proper connection for 9-pin to 9-pin communication is to connect pins 2
to 2, 3 to 3, 5 to 5 (or Tx to Tx, Rx to Rx & Vo to Vo).
For further information, consult manual pg 5-1 through 5-22
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Evan Garrett
Paul Adleman
March 20, 2000
2nd year APKG