Showing results for 
Search instead for 
Did you mean: 

I need to program a pulse on time of day

I am needing to send a pulse out of the HMI ever morning at 02:05 ( 2:05 am) using the PC clock to the PLC clock.  Wanting to synchronize the PC and PLC clocks.

0 Kudos
Message 1 of 9

I think this depends the specific driver\protocol you use.

0 Kudos
Message 2 of 9

I am not sure I understand why driver\protocol I use.  please elebrate.


The PLC and HMI are working now.  I just want to send a digital pulse to the PLC from the HMI ( or PC clock ) at a certain time of day. I have done it on other HMI/PLC but I cannot determine how to do it in NI.

0 Kudos
Message 3 of 9

I think you have to make clear if this function is supported by your PLC, that means if the function is the supported by the protocol and recognized by the hardware,  that is why I ask the specific object for communication you are using in Lookout.

0 Kudos
Message 4 of 9

In the PLC I have logic that when an internal contact is made it will set the clock to a preset time. In this case 02:05:00. This works.

What I now need is for Lookout to read the PC clock and at 02:05:00 send a pulse from the HMI to the PLC internal contact so that the logic in the PLC will set the internal clock to 02:05:00.


I have done this with Rockwell Factory Talk HMI but am unable to find a similar function in NI Lookout to accomplish this.

0 Kudos
Message 5 of 9

You can take this KB as a reference, http://digital.ni.com/public.nsf/allkb/893486CFE12B35F186256E920054EE89, it can tells you how to trigger an action at certain time. Then, if you have a PLC connecting to Lookout , there must be communicaiton between these, that meas, you can read and write data to the registers, you can trigger a register to change this value at a certain time, you can set when PLC get this change, it will sync the time.

0 Kudos
Message 6 of 9

I saw this and have not yet been able to get it to work.  Will keep working on it.  Thought maybe another way.


0 Kudos
Message 7 of 9

Time of Day timer will do this, but there may be a timing issue depending on a few things.

If the PLCs use a shared communications channel serial for example.  With many slaves you will have a delay before the last PLC receives the sync pulse.  We have some systems with 70+ PLCs on a serial bus and can have delays as much as 1-2 minutes for the entire network to get full updates. 



Forshock - Consult.Develop.Solve.
0 Kudos
Message 8 of 9

I will keep the time delay in mind when multiple PLCs used.  Fortunately I have only one PLC to concerned with at this time.  Have been pulled on another project at this time.  Thanks for the information.

0 Kudos
Message 9 of 9