L298 more speed needed

Hi Everyone

I've got a Solarbotics L298 stepper motor driver, various stepper motors nema11, 23, 17, 34, and a Comfiletech Cubloc cb290 PLC embedded controller.
I've read somewhere that the stepper motor is able to rotate at high speed but it's losing torque.
So I need to run a stepper motor around 200 rpm.
The PLC code is written in basic language. The code:

Const Device = CB290
Set Outonly On
Usepin 16, Out, l1
Usepin 17, Out, l2
Usepin 18, Out, l3
Usepin 19, Out, l4
Usepin 14, Out, en1
Usepin 15, Out, en2
Dim a As Byte
Dim b As Byte
Dim c As Integer
Do
c=In(72)

If c=1 Then
High 14
High 15
For a=1 To 200
Byteout 2, 1
Delay 5
Byteout 2, 4
Delay 5
Byteout 2, 2
Delay 5
Byteout 2, 8
Next

End If


The ports 16 to 19 are on the port2, so I can give impulses with byteout like

1000 0000 '(16)
delay x
0100 0000 '(17)
delay x
0010 0000 '(18)
delay x
0001 0000 '(19)
delay x

I've tried with various delays, but the motor won't rotate faster than 60 rpm.
Can anyone help me?

p.s. Sorry for my bad english

I forgot the manual for L298
[solarbotics.com]
And the CB290 (from page 49 )
[www.comfiletech.com]

The L298 is a hopelessly antiquated constant-voltage stepper motor driver chip, completely unsuitable for achieving high speeds. Use a modern constant current stepper motor driver chip or module instead. See the pololu web site for a good selection, or do a search on eBay. I think there is or was another chip, the L297, which can be used with the L298 to turn it into a constant current driver, but that's an ugly, complicated and expensive solution compared to using a modern chip or module.

When you switch to a constant current driver, you will also need to increase the supply voltage. It's normal to use these drivers with e.g. a 12V or 24V supply even if the motor voltage at the rated current is only around 3V. The higher the speed you want, the higher the supply voltage you need.

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Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks for quick answer. I've got a Microstep ZM-2H606 driver too, but the problem is the same. Can't make it rotate faster. I think that the 200 rpm isn't too much at all.

1. What voltage are you running the ZM-2H606 from? It needs to be several times higher than the stepper motor coil voltage to get torque at high speeds.

2. Are you accelerating the motor smoothly? You can't get a stepper motor to move at high speed instantaneously from rest because of the rotor inertia.

Edited 1 time(s). Last edit at 09/10/2015 04:39AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].