FAQ: Is it possible to troubleshoot fieldbus modules that won't respond to PLC commands?
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A. Make sure that main power is on (PWRON bit), and the NS module is ready to communicate (READY bit).
B. Make sure the e-stop bit (ESTP_R) is off. The ESTP_R bit reflects hardware and software e-stop conditions combined. If ESTP_R bit is on, check the status of the EMSTOP wiring and PN81B parameter. The physical EMSTOP input is on the CN4 connector. This input is default to Normally Closed (PN81B bit 1). To disable software e-stop, set ESTP bit ON.
Both the EMSTOP input AND the ESTP bit in the command message need to be set in order for the drive to be out of disabled condition. The EMSTOP input and the ESTP bit will have no effect if PN81B, bit 0 is set to xxx0. This may be useful in unloaded bench-top testing.
C. Make sure the SVON bit has been toggled from 0 to 1. The SVON enable command is edge sensitive.
D. Make sure there are no alarms (ALRM bit). If there is an alarm, clear it by toggling alarm reset bit (ALRST).
E. The SVON bit should be turned on after the ESTP_R = 0. The SVON bit and the ESTP bit cannot be set simultaneously.
Case #2: The drive is enabled and the SVON_R is 1 in the response message, but the motor won't move.
A. Check if a warning is being generated when the command is issued, e.g. the setup value is out of range (A.94), or command reception conditions are not met (A.95).
B. Check the status of the POT and NOT input and Pn819. POT or NOT are never displayed on the LED readout of the SGDH amplifier when used with the NS modules. The inputs are on the CN1 connector. They are set to Normally Closed as default. The status of the POT and NOT input can be read in the response message byte 3, bit 6 and 7. The POT and NOT will have no effect if Pn819 is set to xxx0, which may be useful in unloaded bench-top testing.
C. Make sure starting motion command bit must be toggled from 0 to 1. C_START, FEED, STEP, PTBL, STN, HOME commands are edge sensitive.
D. Make sure the commanded position is different form the actual position. If the INC bit is set to 0, target position is commanded in absolute terms. In this case, if the motor is at position 5000 and a Simple Positioning of 5000 is commanded, the motor should not move.
E. Check the MOD_R bit. If this is 1, the message format for the command response is SET/READ (commonly used for reading/writing parameters). The MOD bit in the command message should be set to 0. This problem is often accompanied by the A.95 alarm, Command Error.
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Please read and understand the product instruction manual before installing, servicing or operating Yaskawa products. FAQ content and illustrations are provided as technical advice to augment the information in manual, not supersede it. It is not possible to give detailed instructions for all types of installation or support activities. The information described in the FAQs are subject to change without notice to improve the product or FAQ. Yaskawa assumes no responsibility for errors or omissions or damages resulting from the use of the information contained in any FAQ. All warnings, cautions and product instruction for product use must be followed. Installation, operation and maintenance should be carried out by qualified personnel. Failure to observe these and other precautions highlighted in the product manuals will expose the user to high voltages resulting in, serious injury or death. Qualified personnel are defined as individuals who are familiar with the installation, starting, operation and maintenance of Yaskawa products of the type described and have proper qualifications to perform the work.
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