AMX UDM-RX02N, Руководство по эксплуатации/справочник

Страница: 67 / 96

UDM-RX02N NetLinx Programming
57 UDM-0808-SIG, UDM-RX02N and UDM-ABB-8-SIG Operation /Reference Guide
Additionally, it can control low traffic two-way devices not dependent on real time feedback. An appropriate
2-way example would be a query of lamp hours from a projector once per hour which is dumped into a
variable for viewing on a touch panel page.
An inappropriate use of serial control of a device via a RX02N would be the control of a verbose device via
programming that is heavily dependent on real time feedback. A 32 byte reply from a device would take
around 7 seconds, so this is significant. Because of this, for example, using a Duet module to control a video
conferencing unit will not work.
When using 2-way communication, the serial port on each RX02N connected to a UDM hub operates
independently, so the host need not wait for the reply from one port before sending data to another – they
operate in parallel, but data to and from the same port must be serialized in order to avoid data loss. The UDM
host would have to send the command and then wait until the reply had been received from the device, before
sending the next command. The UDM-0808 handles incoming serial data in the same way as a normal serial
port so data will arrive at the data event in the usual way. However, the next command should not be sent until
the previous reply has been received in order to avoid Rx data loss.
232 traffic considerations above apply to UDM-0808 and other AMX devices which
incorporate RX02N cat5 receivers such as DVX series.