PRTInchUnits

From Shopbot Wiki

Contents

Inch unit values (Steps per Inch):

The PRT4g upgrade and PRSstandard tools use 1/10 stepping Gecko Drives but earlier PRT tools used several different drivers and could be set to three different microstepping values to give extra resolution. 1/4 stepping divided each step into 4 parts, 1/8 stepping divided it into eight parts, and 1/16 stepping divided each step into sixteen parts.


Once you find the microstepping value for your tool, use that value to select the correct chart below. Then find the correct unit values for your tool in that chart using the gear ratio of your motors and the number of teeth on the pinion gears. The X and Y Axis will be the same but the Z axis will probably have a different pinion size and possibly a different motor gear ratio. Once you've found the correct Unit Values, enter them in the ShopBot Control Software using the [VU] command.


PRSstandard ShopBots and PRT Version4g Board (these tools use 1/10 stepping Gecko Drives)

Number of teeth in pinion
Motor gear ratio 18 20 25 30 36
1:1 707.3553 636.6198 509.2958 424.4132 353.6777
3.6:1 2546.4791 2291.831 1833.465 1527.887 1273.24
7.2:1 5092.9582 4583.662 3666.93 3055.775 2546.479
10:1 7073.553 6366.198 5092.958 4244.132 3536.777
25:1 17683.883 15915.49 12732.4 10610.33 8841.941


PRT 1/4 Stepping (covers most PRTs that were not updated to Version4g boards)

Number of teeth in pinion
Motor gear ratio 18 20 25 30 36
1:1 282.94212 254.6479 203.7183 169.7653 141.4711
3.6:1 1018.5916 916.7325 733.386 611.155 509.2958
7.2:1 2037.1833 1833.465 1466.772 1222.31 1018.592
10:1 2829.4212 2546.479 2037.183 1697.653 1414.711
25:1 7073.553 6366.198 5092.958 4244.132 3536.777


PRT 1/8 stepping (early and specialty PRTs)

Number of teeth in pinion
Motor gear ratio 18 20 25 30 36
1:1 565.88424 509.2956 407.4367 339.5305 282.9421
3.6:1 2037.1833 1833.465 1466.772 1222.31 1018.592
7.2:1 4074.3665 3666.93 2933.544 2444.62 2037.183
10:1 5658.8424 5082.958 4074.367 3395.305 2829.421
25:1 14147.106 12732.4 10185.92 8488.264 7073.553


PRT 1/16 stepping (specialty PRTs, few)

Number of teeth in pinion
Motor gear ratio 18 20 25 30 36
1:1 1131.7685 1018.592 814.8733 679.0611 565.8842
3.6:1 4074.3665 3666.93 2933.544 2444.62 2037.183
7.2:1 8148.7331 7333.86 5867.088 4889.24 4074.3665
10:1 11317.685 10185.92 8148.733 6790.611 5658.842
25:1 28294.212 25464.79 20371.83 16976.53 13147.11
Personal tools