When I watch TV I use my receiver for sound reproduction via HDMI cable between the two equipments. Unfortunately they have to be powered up in a certain way to function. First the TV must be switched on and after a delay of approximately 5 sec. the AVR can be switched on. If the AVR is switched on too early the sound from the TV is missing.

Is there a possibility to program the remote control to power up the AVR with a delay of 4-5 sec. or more?

You would have to contact Harmony support to have them insert a delay between the two devices powering up, it is not something we can do as users.

I believe that you can do this if you add a power-on delay of 4-5 seconds to your tv device in the Harmony software. That way the remote will wait 4-5 seconds before sending the next command. You may need to add a start up 'dummy' command to the TV in between in order for the 4-5 seconds to happen before the AVR turns on.
Let me know if you want to try this and if you need step-by-step instructions.
Happy New Year,
RC

The Power On delay is the time the Harmony will wait before sending another command to that device. It will not prevent the Harmony from sending commands to other devices. However, the TV 4-5 seconds power on delay may cure your problem due to some annoying HDMI handshaking issues. Also, since HDMI is "two way", this connection can be used to communicate between devices to have one device turn another on, or tune to that input, etc. This can interfere with your intent (especially when using programmable remotes like the Harmony). Thus you should go to the user menus for both devices to turn this "auto-tune" feature off (sometimes called EZ-Sync, Viera Link, AnyNet, BD-Wise, or similar).

Note: You can change the powering order under the Activity > Settings > Review the order in which devices are powered on.

If these suggestions do not cure your problem, then as mentioned by rehaz1, you will have to contact Harmony support to have them insert a delay between the two devices powering up.

Or you could cheat and tell the software your device does not have power commands. So when you enter the activity, the device stays off. You add a delay in the startup sequence and then you add the power on command for the device.

Then you add the power off command for the device for when you leave the activity.

(sorry for resurrecting a very old discussion, maybe there are more advanced techniques nowadays, but I found this while searching for a solution for myself and I thought about sharing)

Well, while we're sharing... in case people don't know this... in the software ("MyHarmony"), you can chose the device that requires a delay by clicking "Devices", then "Change Device Settings", then "Power Settings", then...(whichever choice you prefer here and again for the next screen), until you get to the "Power Settings" menu screen. Under the "Power On" command, click the pen under "Edit", and raise the 0.0 sec. under "Duration" to whatever delay you want. (You can also do this for power off).

n.b. You can also add delays between Activity steps under "Customize Activity".