Page Comparison

Enter the Master Channel name.

This is the name which appears in the user diagnostics menu, and is also see in an HCP diagnostic window if used with Elecsys HCP. 

In some configurations this may be listed as "Direct Master", which includes a few operational differences noted below. The main differences between the Channel Types are listed below:

Direct Master

• Global Scan Period
• One failed poll changes RTU comms status.

Direct Master Flex Scan

• Scan Period configured for each scan.
• All "effective" polls must fail before RTU comms status fails. 

Select the automatic polling method for the channel.

Automatic polling types supported are:

• Yes – polling started automatically upon power-up
• No – polling started manually through the MMI
• Link Based Poll – polling is started only after a P/R connection has been made from an HCP. 

Enter the response timeout in milliseconds.

Time in milliseconds to wait for a poll response before declaring the message failed.

For Network Circuits, if a scan fails because the socket is broken or interface is unavailable, then the Master Channel protocol will wait a period of time (Response Timeout * 2) to try the next IP address in the Circuit. 

Unused.

Enter the interpoll delay in milliseconds. Use this to add a delay between each poll sent by the channel to any field unit.

Time in milliseconds to wait between each poll. 

The Scan Effective Limit is the time (in seconds) defining which scans in the Scan Table are considered "effective" – meaning, polls which affect the status of the Field Unit if there are poll failures. Scan Table entries which have a Scan Period greater than the Scan Effective Limit do not mark the Field Unit offline when the scan fails.

For instance, if the Scan Effective Limit is configured for 30 seconds, then any scans defined with Scan Period <= 30 will be used to mark the Field unit online or offline. Scans with Scan Period greater than 30 will not mark the Field Unit offline even if they fail. The Scan Effective Limit only applies to the "Direct Master Flex Scan Table" version of the channel object.

A Scan Effective Limit of 0 disables this feature, thus all polls will affect the Field Unit status. 

Enter the network recovery period in seconds.

Time period to wait after an RTU fails, before attempting to re-establish communications with that RTU. This will take the device off scan, allowing other devices on the channel to be polled more frequently and not waste as much time retrying a failed device. 

Click the Edit Table button to define the order and selection of polls to be sent to all field units on this channel, independent of protocol. Field Unit configurations (Modbus, etc.) define the protocol-specific nature of the individual polls that are sent.

Only one Unit Address/Poll Record combination can be entered in the Scan Table. Any subsequent table entries with duplicate Unit Address/Poll Record will be ignored.

Scan Table details:

Unit Address - This is the Field Unit Address as configured in each field unit on this Channel. (To force the Scan Table to ignore the Scan Period, enter a Scan Table row with the Unit Address of -1.) 

Poll Record - This is the row number in the Poll Record in the Field Unit definition. The first row in a Poll Table is referenced as record 1. Only those polls which are to be polled continuously need to be listed in this Scan Table. 

Scan Period - Enter the scan period in seconds. The Scan Period is the amount of time to use for scheduling each scan (global for all scans in the Direct Master, or configured per scan row in the Direct Master Flex Scan Table). 

For the Direct Master, the channel will restart the scan table sequence after the Scan Period has expired. If the total time for a given channel exceeds the scan period, the next scan shall be scheduled immediately.

For the Direct Master Flex Scan Table, each poll is scheduled based on its own Scan Period. If the total time required for scans at any point is greater than allowed by the Scan Periods, the scans will operate as fast as possible. 

Setting a Scan Period to a negative number will disable a scan. However, the first entry in the Scan Table for each Unit Address should not be disabled, or it may not correctly set the Alive/Dead status of the unit. 

Comment - Optional column, allowing a descriptive comment to be entered for each row in the table. The Comment field is unused in the configuration.