Sequence Timing

Next to sending the right commands, timing is the most important consideration, when creating devices. The timing between two RS-232 commands are different depending on the action your device takes when receiving the command.

Some manufacturers do supply the waiting times, but most do not. In the latter case you have to find a stopwatch and determine your own times. Remember that the timing can change from device to device even when the devices come from the same manufacturer.

Be aware of projectors where the warm up time and cooling time can change a lot, depending on the model number (largely related to the lumen output of that model). There are two reasons why timing is important: First, because sending commands to a projector/device that is not ready, will make the device ignore the command or even stop the device from handling further commands sent to it. Second- and most importantly - all the delays that you enter will be used by the control system to indicate (by LED) when your device is ready to be controlled and when it is not. Also the times are used to “lock” the keyboard, so that unwanted
action can be prevented.

So when you enter times in your device, keep in mind that it is preferable to enter a longer delay than a shorter delay. A good rule when measuring for example warm up time on a projector is to add 1 or 2 seconds, just to be on the safe side.