With Motion Control, how do you diagnose the configuration error if you do not get any valid encoder values with the modules TM PosInput and TM Count?
There are the following differences between the TM PosInput and TM Count modules.
With TM Count (high-speed counter module), incremental encoders are read in with HTL signals.
With TM PosInput (travel path acquisition module), incremental or SSI encoders are read in with RS 422 or TTL signals.
Enable the diagnostics monitoring for the TM PosInput module to have more precise diagnostics of the above-mentioned error message. Proceed as follows in STEP 7 (TIA Portal):
- Open the Properties in the device configuration for the module and navigate to the "Diagnostic interrupts" dialog.
- Enable the two diagnostic interrupts:
- Enable diagnostic interrupt on wire break
- Enable additional diagnostic interrupts
- Save and compile your station via the two menu commands
- "Compile > Hardware (rebuild all)" und
- "Compile > Software (rebuild all blocks)".
- Load the station into the CPU.
- Via the "Online & Diagnostics" function in STEP 7 (TIA Portal) you can evaluate the diagnostics in the diagnostic buffer.
If you diagnose a wire break for the TM PosInput module, check the wiring of the front connector and measure the voltage on the two channels. The difference in voltage between A and /A and between B and /B must be about 2V. If the value is not reached, the module reports a wire break. In the case of wired, differential, serial data transmission (RS-422), when operating with SSI encoders, current must always flow between A and /A (or D and /D) and in the opposite direction between B and /B (or C and /C). If not, no valid encoder signal is recognized and in Motion Control you get the message that the TM module has not started up or has not been initialized.
The error message received from the TM module
Technical data, description and wiring diagram of the encoder
Firmware version of the TM module
If possible, measure the phase sequence of the signals of the connections A+/A, B+/B and N+/N via a scope. In this way you can also check the voltage excursion of about 2V between the above-mentioned connections.
The signals of the connections A and B must be set at 90° to each other.
The signal for N must be True if the signals for A and B overlap (offset by 45° to A and B).
The negated signals must be set at 180° to the non-negated signals.
Furthermore, you can also recognize EMC problems or wiring faults from the shape of the signals.
If you disable diagnostics in the device properties, you can also diagnose the message directly on the module.
An encoder is connected to a TM Count or TM PosInput module and via Motion Control you get this message: "Configuration error encoder driver 58, encoder driver not initialized during startup". In the device configuration you switch to Online Mode and open the module's dialog "Online & Diagnostics". In the "Diagnostic status" tab you receive detailed diagnostics allowing you to clear the cause.
Enable the diagnostics interrupts for all modules and in the device properties of the modules under "Diagnostics" you enable all the options to ensure that diagnostics of all errors.
Detailed information is available in the manual "SIMATIC S7-1500 TM PosInput 2", under Connections.
The screen in this FAQ response was created with STEP 7 (TIA Portal) V14.