Digital Caliper Types Supported

 

The inexpensive Chinese calipers available on the market can be divided into two types (types A and B). The major difference between them is the data interface’s protocol. Type A: The data is transmitted in two 24bit long data packages (see fig. 1). Type B: Seven 4bit long data packages are sent (see fig. 2). The Caliper2PC Interface supports both caliper types. During initialization all ports are scanned and the caliper types connected are recognized automatically. It is characteristic of both caliper types, A and B, that the battery’s positive pole is connected to the ground / the caliper’s body. To find out the caliper’s type, the battery’s positive pole can be connected to the caliper’s body, using a short cable. This causes a short circuit of the battery. If the caliper turns itself off, it is neither a type A nor a type B caliper. Adapters are available for BIN6 calipers (6x4bit protocol with battery’s negative pole connected to the caliper’s body), iGaging DigiMAG scales (21bit protocol) and linear glass scales with 5V TTL quadrature output (A, B, Z). Hence most linear encoders available on the market are compatible with the Caliper2PC system.

 

  fig. 1: Caliper Clock- and Data Sylvac Protocol (48 bit 2X24 Type A)                          fig. 2: Caliper Clock- and Data 7-BCD Protocol (28 bit 7X4 Type B)

 

For some encoders (e.g. fig. 10) it is recommendable to reinforce the soldered connection after soldering with 2-component-adhesive to make it mechanically more sturdy. In the following figures different retrofitted calipers are shown, according to their protocols.

Calipers Type A:

 

  fig. 5: 150 mm 6" Digital Caliper Vernier                                                                 fig. 6: Data cable connected through small plasic cover

 

  fig. 7: 150 mm 6" Digital Caliper Vernier                                                                  fig. 8: Data cable inserted next to plastic cover

 

  fig. 9: Short Digital Caliper Vernier Type A                                                             fig. 10: Pin Out Digital Caliper Vernier Encoder Type A

 

 

Calipers Type B:

  fig. 11: 150 mm 6" Digital Caliper Vernier Type B                                                    fig. 12: Encoder enclosure without port cut Type B

 

  fig. 13: 150 mm 6" Digital Caliper Vernier Type B                                                    fig. 14: Encoder enclosure without port cut Type B

 

  fig. 15: 150 mm 6" Digital Caliper Vernier Type B                                                    fig. 16: Encoder enclosure with port cut Type B

 

 

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Copyright © Dipl.-Ing. Tomer Lanzman. All rights reserved.