Issue
Can a Niagara R2 UNC and a SIGNAL software-based computer simultaneously communicate to and poll values from a GCM-84000?
The UNC would be interfaced serially to the GCM and SIGNAL would communicate over the GCM-LAN.
Environment
Niagara R2 UNC with the Network 8000 GCM driver, all versions
SIGNAL, any version
GCM-84000 series
GCM-86000 series
Cause
The GCM cannot adequately process polling from more than one HMI.
Resolution
Although this architecture is physically possible to configure, it goes against the Best Practices of the Niagara Network 8000 Serial Driver. Here is the excerpt from the Best Practices section of the driver manual (F-27070):
When using the I/A Series Niagara Framework to poll a GCM network while simultaneously polling the same system with another Human Machine Interface (HMI) problems can occur. It is recommended that if the I/A Series Niagara Framework is to be used it should be the only system polling the NETWORK 8000 hardware. In particular, this should be noted that in the case of certain HMI systems (InVue™ and UltiVist™, for example), it may not always be obvious that there is something else polling the same hardware. These systems could be polling the same hardware by the Ethernet connection.