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X and Y Motor Connectors, Wiring the Motor

The following table summarizes the currently released stepper motor control product key capabilities when using our non-current-controlled models.  Note that the double current mode (using a single motor) is only available using firmware version 1.59 or later.   You will want to review the calculating motor current faq in order to determine the current requirements for your motor.

Product Unipolar Bipolar Current/Winding with 2 motors Current/Winding with 1 motor Motor Voltages
SS1010USB x   0.5 to 1.0  Amp not supported 5-26
BS1010 x x 1.0 Amp 2.0 Amp 5-34

The following table summarizes the currently released stepper motor control product key capabilities when using our current-controlled models.   These products require only that you select a power supply whose voltage and current can handle your stepper motor.   You will first want to review the calculating motor current for current controlled products faq in order to determine the current and voltage requirements for your motor.

Product Unipolar Bipolar Maximum Number of Motors Current/ Winding, each motor Motor Voltages
BC2D20   x 2 0.2-1.5 Amp up to 34
BC4E20   x 4 0.2-1.5 Amp up to 34

All of the products have multiple identical connectors (labeled the W, X, Y and Z connectors. depending on how many motors are capable of being operated by the controller) which are used to operate to the X and Y motors, respectively. They are wired as follows for the all products except the BiStepA04 (pins counting from top to bottom).

Pin Name Description
1 GND or +V If BiStep board, GND; if SimStep or UCC30xx board, +V
2 WB2 Winding B, pin 2
3 WB1 Winding B, pin 1
4 WA2 Winding A, pin 2
5 WA1 Winding A, pin 1
6 GND or +V If BiStep board, GND; if SimStep or UCC30xx board, +V

This pinout was selected to allow a simple reversing of the connector (i.e., take it out and turn it around) to reverse the direction of the motor, and for simpler connection to unipolar motors.

 

Single Motor, Double Current Mode of operation

Starting with GenStepper firmware version 1.59 and above, our SimStep and BiStep products can now be configured to operate a single motor at twice the rated capacity of the board

All of the drivers on many of our boards (see the table at the top of this page) can be operated in parallel, in order to double the current available.  However, due to timing issues, our updates to each motor are usually offset by 8 microseconds; therefore, in prior firmware releases, you could not simply connect a single motor to the X and Y connectors in parallel, and expect correct operation of the system -- even if you always ran both motors identically.  Actually, you would be shorting power to ground!

Starting with GenStepper version 1.59, you can configure the board to send the same signal to the Y motor as is sent to the X motor (with the internal Y operations ignored).  If you then wire your motor to BOTH the X and Y connectors (in exact parallel, so that WA1 from both the X and Y connectors is connected to your Winding A, pin 1 of your motor), then the board can provide double its normal per-winding capacity.  This is only available with the GenStepper firmware!

You configure the board to operate this way by GROUNDING both the LY- and LY+ signals from the J1b connector (also called the A0 and A1 lines).  This tells the board that there is no separate Y motor, so it directs the output system to duplicate all X motor signals on the Y connector.  You then wire your motor to BOTH the X and Y connectors (as described above); double the current will be available.  Please note that if you do not correctly do the above wiring, then you will not get the benefit of the double power mode, and the board is quite likely to fail.

Stepping Sequence, testing your connection

The current is run through these connectors to generate a clockwise sequence as follows:

 

Step

WB2

WB1

WA2

WA1

0

0

0

0

1

1

0

1

0

1

2

0

1

0

0

3

0

1

1

0

4

0

0

1

0

5

1

0

1

0

6

1

0

0

0

7

1

0

0

1

 

Note also that it is explicitly legal when using the GenStepper firmware to operate your motor in “double current, ½ power mode”.  In “double current” mode, you wire your motor to both the X and Y motor connectors, and you jumper the “LY-” and “LY+” signals to ground to tell the board that double current mode is enabled.  In all other respects, you follow the rest of the instructions in this manual.

The actual wiring configuration to connect to a given stepper motor depends on the motor type.  For most unipolar motors, each winding has three leads.  The center-tap (shown in the above schematics as “COMMON-A” or “COMMON-B”) is connected to the GND signal in the BiStep series controllers, or to +Vm on the SimStep/SS0705 series of controllers.  The other two leads are connected to pins WA-1 and WA-2 or WB-1 and WB-2, as shown in the above schematics.  For bipolar motors, the windings match the labels – that is to say, pins 2-3 are for winding B, and 4-5 are for winding A.  Note that the unipolar motors will also match the labels, but it may be more difficult to identify the windings.

Determining Lead Winding Wire Pairs

If there is no manufacturer’s wiring diagram available, unipolar and bipolar motor windings can both often be identified with an ohm-meter by performing tests of their resistances between the motor leads.  

For any motor, number the leads (from 1 to 4 for a bipolar motor, from 1 to 5 or 6 for a unipolar motor).  Then measure the resistances and record the values in the empty cells in a table like the following:

 

 

1

2

3

4

5

6

1

-

 

 

 

 

 

2

-

-

 

 

 

 

3

-

-

-

 

 

 

4

-

-

-

-

 

 

5

-

-

-

-

-

 

6

-

-

-

-

-

-

 

For example, the cell at location (1,2) would be filled in with the resistance between leads 1 and 2.  The ‘-‘ entries show values which do not need to be separately measured, since they are already measured in another row/column pair (or are a self-reading).  For example, having measured the resistance between leads 1 and 2 to fill in cell (1,2), there is no reason to separately measure leads 2 and 1!  If you have fewer leads than those shown in the table, ignore the rows and columns with the nonexistent leads.

For a 4-wire bipolar motor, the low-resistance pairs are the opposite ends of matching windings; high-resistance pairs are different windings.  For example, if cell (1,2) shows 10 ohms, while (1,3) shows greater than 1000 ohms, then wires 1 and 2 can be called winding A, while wires 3 and 4 can be called winding B.

For a 5-wire unipolar motor, you will observe 2 reading values in the resulting table, with the higher reading being about double that of the lower reading.  The single line which has the lower reading on all of its entries in the table is the common lead; the other wires are the winding leads (unfortunately, this test cannot show which is winding A and which is winding B through resistances alone).


For a 6-wire unipolar motor, you will observe 3 reading values in the resulting table.

·        If you see a single reading near 0, then the two leads associated with that reading are the common leads, and the remaining 4 wires are the windings WA1, WA2, WB1 and WB2 (this test cannot determine which is winding A or B through resistances alone).   As a check, you can observe that all readings between the other wires and either of the 2 common  wires have value ½ that of all of the readings between the non-common wires.

·        Otherwise, you will see readings which are near infinity (which identify leads from different windings), are at some value (such as 10), or are at double that value (such as 20).  The pairs which show the “double value” are the opposite ends of a given winding (i.e., WA1 and WA2, or WB1 and WB2).  The remaining wires are the “common” leads for their given windings.

 

A 6-wire 4-phase unipolar motor will have two “common” wires.  You will normally connect one of the wires to pin 1, and the other to pin 6.  However, you can often operate a 6-wire unipolar motor as if it were a 4-wire bipolar motor (when using the BiStep series of controllers) by insulating the common leads and leaving them disconnected.  When it works, this usually provides more torque for the motor, but it requires double the voltage (at the same level of current) from the power supply.  You cannot operate with this pair of wires disconnected if they are connected together inside the stepper motor -- if the resistance between the common leads is very low (less than 10 ohms), such a connection exists and you must therefore operate using the regular unipolar wiring scheme.


 

Sequence Testing

Always double check all of your power and motor connections before you apply power to the system.  If you have reversed any power leads, you will blow out our board and you may blow out your power supply!  If you are operating a unipolar motor and you short a common lead to a winding pin (WA or WB), then you will blow out our drivers!  Similarly, any winding which is shorted to any other winding may burn out our board.  If you are setting up to use double-power mode (connecting one motor to both the X and Y motor connectors in order to drive a larger motor), failure to connect the LY- and LY+ limit inputs both to ground will also cause the board to fail.  None of these issues are warranted failures; repairs for such are not covered!

After winding lines have been determined, identifying a running sequence can be done by testing the lines using following sequence, connecting to the X motor with clip leads.  Turn off power to the board in between each test, so that power is not on while you change the wiring.  For your initial testing, use a power supply voltage of 2 times the official voltage for your motor (since we are operating in ½ power mode as part of this test).  This will always be less than what you will determine is the “best” supply value, but it will be adequate for these tests.  Be sure to keep your supply voltage within the range supported by your controller!

For wires A, B, C, and D (where A, B, C, and D are initially connected to the WA1, WA2, WB1, and WB2 lines) try these orders:

             

 

WA1

WA2

WB1

WB2

1.

A

B

C

D

2.

A

B

D

C

3.

A

D

B

C

4.

A

D

C

B

5.

A

C

D

B

6.

A

C

B

D

 


 

For each pattern, request a motor motion in each direction using the applicable technique:

·        UCDualStepper Firmware (with the UCC30xx series), using a terminal emulator:

o       Issue the correct "H" command to select the right current level for your motor.  See the "UCDualStepper" manual for details of this command.

o       Issue the command “x1000gi0gi”, which should cause the motor to spin to logical location 1000, then back to 0.  Wait for the “*” response after each sub-command (the “h”, “x”, “g”, and “i” commands) before typing the next command, in order to let the firmware finish processing the request.

·        GenStepper Firmware, using a terminal emulator:

o       Issue the command “x1000gi0gi”, which should cause the motor to spin to logical location 1000, then back to 0.  Wait for the “*” response after each sub-command (the “h”, “x”, “g”, and “i” commands) before typing the next command, in order to let the firmware finish processing the request.

·        NCStepper Firmware, using a terminal emulator:

o       Issue the command “1000xg0xgi”, which should cause the motor to spin to logical location 1000, then back to 0.  Wait for the “*” response after each sub-command (the “h”, “x”, “g”, and “i” commands) before typing the next command, in order to let the firmware finish processing the request.

·        UCDualStepper Firmware (with the UCC30xx series), using a terminal emulator:

o       Issue the correct "H" command to select the right current level for your motor.  See the "UCDualStepper" manual for details of this command.

o       Issue the command “x1000gi0gi”, which should cause the motor to spin to logical location 1000, then back to 0.  Wait for the “*” response after each sub-command (the “h”, “x”, “g”, and “i” commands) before typing the next command, in order to let the firmware finish processing the request.

·        UCNCStepper Firmware, using a terminal emulator:

o       Issue the correct "H" command to select the right current level for your motor.  See the "UCNCStepper" manual for details of this command.

o       Issue the command “1000xg0xgi”, which should cause the motor to spin to logical location 1000, then back to 0.  Wait for the “*” response after each sub-command (the “h”, “x”, “g”, and “i” commands) before typing the next command, in order to let the firmware finish processing the request.

Only when the motor is wired correctly will you get smooth motion first in one direction and then the other.

Once a possible pattern has been determined, you may find that the direction of rotation is reversed from that desired.  To reverse the rotation direction, you can either turn the connector around (this may be the easiest method, if a SIP style connector is used), or you can swap both the WA (swap pin 2 with pin 3) and WB pins (swap pin 4 with pin 5).  For example, to reverse

      A B C D, rewire as

      B A D C.

For the purposes of testing, the default power-on rate of 100 ½-steps/second should work with most motors. Otherwise, use the serial connection to define the precise rate needed.