Background
The SICK Stegmann SNS series of encoders are one of their first encoder offerings to use the Hiperface serial output. These legacy encoders are a bit more complicated to test than newer models like SRS/SRM and SKS/SKM. The serial line is also shared with the index line. The encoder first starts in serial mode where you can read memory data (if present), then a command button in the software tells it to change to index mode for alignment purposes. Our newest Athena software offers fixes to our legacy SNS software which makes testing much simpler and less prone to crashing, however, we recommend you follow the sequence below in most cases.
Test Sequence
- Connect the encoder to the TI-5000JX using the appropriate Stegmann SNS cable and the TI-5104 Adapter Module. Note: Make sure your test cable has the index pulse and serial channels wired together. This means that J1 pins 7, 9, and 11 should be jumpered together, and pins 8, 10, and 12 as well. If you are connecting directly with the TI-5069 test cable then you will need to add jumpers from pins 9/11 to 7, and pins 10/12 to 8.
- Select the Stegmann SNS Hiperface encoder.
- In the Data Display, the Encoder ID box should say SNS OK. That means that it has read the SNS
encoder ID from the serial lines, and it is telling you that you have selected the correct encoder.
Obviously this also tells you that the serial lines are functional and that you are receiving data from the encoder. The normal box for indicating receiving data is not functional for the SNS encoder. The INTERNAL ERROR box should say OK. If it says ALARM, it will also display a 2 digit hex code describing the alarm. A code of FF usually means that it is not sending any data. This could mean anything from a cabling problem to a bad encoder. When you turn the encoder (or motor) shaft CW (facing the shaft), the Count should increment and decrement when turned CCW. Remember that this is not absolute position data and cannot be used for alignment. The mechanical and electrical angle boxes will contain dashes because the data is not absolute. - If the motor is an Allen Bradley or Fagor, and if you have these memory options, you can click on the Memory Test button to perform a memory test. The memory data will be displayed, and you can check for correct checksum results. If it is not an Allen Bradley or Fagor motor, the data displayed will be meaningless. However, in either case, you can click the Save Encoder Data File button to save the data to your PC.
- Click on the Data Display button to return to the Data Display. Click on the Sin/Cos Commutation radio button, and the display should change to the sin/cos display. The individual cosine and sine readings are displayed as well as the A and B channel differential voltages that caused them. There will now be data in the mechanical and electrical angle boxes because the sin/cos signals produce absolute position data. You can record static lockup rotor angles if the motor is a permanent magnet brushless type. You must set the POLES selection to the correct number of poles, and for documentation purposes (saving reports), you should set the LOCKUP selection to the voltage polarity that you are using for the lockup. These angles will be similar to the angles you will get using the 4096 count, but they will not be exact. In order to get more exact results form the sin/cos, the correction data from the memory must be used. The software does not currently make corrections using this data.
- Click on the 4096 Count/Rev radio button to go back to the incremental mode. Again the angles boxes will contain dashes because the position data is not absolute. Click on the Enable Z Pulse button so that the encoder will begin providing an index pulse. Several of the boxes will become disabled, and the INDEX box will be come enabled and probably show ALARM. Rotate the shaft until the INDEX box changes to OK. This will mean that you have indexed the encoder. If this does not occur after turning an entire revolution, you may have a problem with the encoder or cabling. When the encoder is indexed, the angle boxes will again show data because the incremental channels are now providing absolute data. This data can be used to check or set alignment by static lockup of the rotor if the motor is a permanent magnet brushless type. You must set the POLES selection to the correct number of poles, and for documentation purposes, you should set the LOCKUP selection to the voltage polarity that you are using for the lockup.
- Once the index pulse is enabled, a standard Count Test may be performed on the encoder. Click on
the Count Test button and perform the Count Test in the normal manner. - The TI-3000JX Generic Hiperface selection contains an SNS option for running your motor.
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