• We will be performing upgrades on the forums and server over the weekend. The forums may be unavailable multiple times for up to an hour each. Thank you for your patience and understanding as we work to make the forums even better.

Enable Input True

Learn the NEC with Mike Holt now!
Status
Not open for further replies.
M

mannyb

Senior Member
Location
Florida
Occupation
Electrician
What is meant when the instructions ask you Enable Input True ? Are they asking if the input terminals has power? Thanks for any help
 
synchro

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
That probably means that there's a property called "Enable Input" that you can program to either the True or the False state. If it's programmed to the True state then the "Enable Input" function is turned on and activated such that the device will accept and use this input. Now what that input actually is (i.e., power, external control, etc.) would depend on the device.
 
ptonsparky

ptonsparky

Tom
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
synchro said:
That probably means that there's a property called "Enable Input" that you can program to either the True or the False state. If it's programmed to the True state then the "Enable Input" function is turned on and activated such that the device will accept and use this input. Now what that input actually is (i.e., power, external control, etc.) would depend on the device.
Click to expand...
I like your answer better.

IIRC, most seem to be enabled already, you have to choose what they are used for. I have disabled a few but generally leave them at factory default.
 
ptonsparky

ptonsparky

Tom
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
nik147 said:
The INPUT is what sort of electrical system you need to supply to the adapter (i.e. what your power company supplies). The OUTPUT is what is supplied to your device. Note that he amount of DC electrical power is calculated by multiplying the current by the voltage (P=I. · V)
Click to expand...
I believe the OP has power to the drive. He now needs to get power out of it. Assume the drive is functional.

Digital Inputs can be assigned one of several functions or not used. Disabled/enabled. One of those DI is assigned the function of allowing the VFD to start or Enable. Think of it as an E Stop. That input must be True, voltage applied, for the VFD to have an output no matter where the control is from.
 
Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
On some VFD enable inputs, “enable true” means that for the drive to function, the input must be True (High, On, contact closed), or it can be set to “enable false”, meaning that the input must be False (Low, Off, contact open). If you enable false, you need a contact closure to DISABLE the drive, which is not considered fail safe. But in rare cases you may want that, for example where disabling a drive may actually create a MORE dangerous situation, such as losing controlled decel or braking, because a disable command just immediately disallows the transistors to fire no matter what. Most drives I have seen either don’t give you that choice, meaning you must do it in external logic, or the default is enable true, and you must go into advanced programming to change it.
 
G

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
If there is a problem with the hardware of the Enable input, then changing from Enable True to Enable False might allow the drive to think that Enable is properly asserted. Not a real solution, since it would mean that there is no Enable functionality available for safe operation, but it would be an interesting diagnostic.
Can you change the value of that setting?
 
Status
Not open for further replies.
Top