Control Techniques has an obsolete line of motors known as the SL series. They can come with a proprietary feedback listed in their manuals as "CT-Coder + SLM3 Electronics". This CT-Coder is made by SICK Stegmann but does not function like the more common Hiperface serial encoders (SNS, SRM, etc). Instead it functions more like a Generic Incremental Encoder with Sin/Cos commutation, like the Heidenhain ERN1387. The CT-Coder also has four data lines (CS, DI, D0, SK) and an EEPROM which stores encoder parameters that can be adjusted such as counts/rev, motor poles, etc. We do not support using these data programming lines, and Stegmann likely does not support it on their testers either since it is proprietary to Control Techniques.
The CT-Coder feedback is then routed into an "SLM3" electronics board within the motor feedback cover. This terminates to a 5 pin circular connector as the main motor feedback connection. While we do offer limited support for testing the CT-Coder directly, we do not support the SLM3 board. The only way to properly test the SLM3 output is to use the corresponding Control Techniques drive. Even if the encoder is testing well directly, the SLM3 board could be damaged and cause issues.
Since both the motor and encoder are now obsolete, there are very few options for replacing the encoder aside from finding spare parts on eBay or similar. Customers with these motors have been told by Control Techniques to update their machines.
Here is a document which details the testing of these unique feedbacks on our systems: https://www.dropbox.com/s/p66t4qkvffq40zg/MEMO_TI-5724_Testing_Stegmann_CT-Coder.pdf?dl=0