Modbus Slave Devices; Table 14 Modbus Slave Status - Honeywell 900 User Manual

Modbus Slave Devices

Modbus Slave Devices
This display gives you an overview of the individual Modbus or Modbus/TCP slave devices attached to the
controller. Navigate to the desired device to see its status.
Item
Slave Name
Slave Address
In Scan
Comm Quality
Messages Received
Data Link Errors
Application Errors
Scan Enabled
Revision 9
May 2014

Table 14 Modbus Slave Status

Name of slave device.
For Modus: 1-247 or 255. For Modbus/TCP: IP address.
Current scan status of slave device.
YES : The slave device is being scanned at its optimum rate. The scan rate is
computed by the controller.
NO: The slave device is being scanned at a reduced rate, or it is not being scanned
at all. The possible reasons are:
•
SCAN ENABLED is set to NO.
•
COMM QUALITY is NONE or BAD.
•
the Modbus address of the slave device is set to 255.
•
the slave device is not defined in the controller configuration.
•
The RS-232 port protocol is not set to one of the Modbus Master protocols.
NONE: This slave device is not defined in the controller configuration.
GOOD : The slave device is being scanned at its optimum rate because its operation
on the communications link is acceptable.
BAD : The slave device is being scanned at a reduced rate because it has
experienced an abnormal number of failed responses. Refer to the section
"Troubleshooting a Comm Quality Problem" below.
The number of messages that were received and processed correctly since the last
controller Cold Start.
The number of basic link-level errors generated by this slave since the last controller
Cold Start. Refer to the section "Troubleshooting Data Link Errors" for more
information.
The number of application errors generated by this slave since the last controller
Cold Start. Application errors are messages that the slave device responded to with
an exception code. For example, application errors can be caused by (a) writing to a
read-only register, (b) accessing a register that is not supported by the slave device,
or (c) using a Modbus function code that is not supported by the slave device.
YES : Scanning has been enabled
NO : Scanning has been disabled
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