User Guide

FS-8700-123 MetOne Particle Counter Serial Driver Manual Page 3 of 26
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1. MetOne Particle Counter Serial Description
The MetOne Particle Counter Serial driver allows the FieldServer to transfer data to and from
devices over RS-232 or RS-485 using MetOne Particle Counter Serial protocol.
This driver is based on a specification called “Standard Protocol FX (enhanced)” ENG110
Revision A dated 1999 by Pacific Scientific Instruments. This protocol provides an interface to
Particle Counters manufactured by HACH Ultra Analytics and labeled as METONE products.
Pacific Scientific Instruments is a former name of Hach.
The primary purpose of the driver is to obtain the current particle counts, but it does allow for
limited control and configuration of some counter parameters. While the driver provides Client
and Server emulation, the Server side of the driver is intended to support FieldServer’s Quality
Assurance program and is not intended to provide complete emulation of a MetOne Counter.
Thus the Server side is not fully documented and is not supported. At a customer’s request the
Server side functionality can be documented and enhanced. If you are interested in this
functionality, then please contact FieldServer’s sales group.
When configured as a Client the driver can start/stop a unit from sampling, change its mode, set
and get sample and hold times, startup or standby a unit and retrieve its current sample value.
Whenever the driver stores a sample value, it will also store a timestamp of when the record
was obtained.
In the configuration of the FieldServer each device is identified by specifying its device number
then the sub-device code or port number and finally by a device type. The device type will be
used to interpret the status byte obtained from the device.
For each configured node, each time the FieldServer sends a message to the device it will
select the device (and the select the sub-device or port if specified) and then the message will
be sent. If the most recent message sent was sent to the device, the driver will do the selection
to ensure the correct device response.
When the current record is read from a device then the driver will store the data extracted from
the response in a range of consecutive Data Array elements so that these values can be served
to another protocol. Even though the record data contains a time stamp, the driver will make its
own time stamp for new data. If there is no current record the driver will not update the data.
If the response is invalid in any way – invalid characters or invalid checksum the driver will
ignore the message and not store any data.
Max Nodes Supported
FieldServer mode Nodes Comments
Client 1
There can only be one Client node per FieldServer port.
The driver can poll any number of Server nodes provided
that they comply with the vendors numbering requirements
Server
Driver as a Server is not documented or supported. Used
only for QA purposes.