About SNP and SNPX Communications
The SNP Communications enabler uses the Series Ninety Protocol (SNP) to communicate with Series 90 controllers over a serial line.
The SNPX Communications enabler uses the SNPX protocol to communicate with Series 90-30 controllers over a serial line.
SNP and SNPX are half-duplex protocols that uses the RS-485 (enhanced version of RS-422) and RS-232 electrical interfaces. These protocols permit communication between one master and one or more slaves. Communication between CIMPLICITY software and Series 90 controllers may be set up as a point-to-point connection or a multi-drop configuration. Connections may be established on the RS-485 CPU port of the Series 90 or via the CMM card.
Both enablers support the following CIMPLICITY features:
- Polled reads at user defined rates
- Poll after setpoint
- Triggered reads
- Analog deadband
- Alarm on communications failure
- Server Redundancy configurations
Both enablers support the following data types:
- Signed 8, 16, and 32 bit integer
- Unsigned 8, 16, and 32 bit integer
- Floating point
- Text
- Arrays