jeremychoate (Customer) asked a question.
Hello,
I'm using a Click Ethernet PLC and SCL to communicate with a STP-DRV-4850 drive.
I notice in the documentation for the SCL language that the the homing function (Seek Home - SH) utilizes a home sensor wired to the EN input of the drive. I had already planned to use the EN input as part of my e-stop circuit (disabling the drive when an e-stop condition occurs).
I have two questions:
1) If I use the EN input as part of my safety circuit, would I be disallowed from using the Seek Home function and would be required to "roll my own" homing routine using a standard input on the PLC for the home sensor?
2) If I used the EN input for my home sensor, what else is an acceptable method for isolating power to the motor during an e-stop condition? Would it be acceptable to merely switch power to the drive itself at the VDC+ terminal?
Thanks for any help you could provide.
Hi Jeremy,
The enable input is not acceptable for any E-stop circuit since it's non-redundant, non-monitored, and 'active' disable (drive is off when enable is on). Same with small DC drives. Safety does not seem to be considered in their product range.
I would remove drive power during an E-stop since that's your only other option. You can't disconnect the motor leads when the drive is powered (that could blow the output stage).
Adisharr,
Thanks so much for your very informative reply! I was afraid that might be the case, but your suggestion is incredibly helpful.
Sure thing Jeremy!