Controller Properties Dialog Box - System Protocol Tab Overview

NOTE:
Logix Designer versions 37 and later do not support controllers with serial ports. This topic applies only to Logix Designer versions 36 and earlier.
This tab is not visible when configuring a controller that does not have a serial port. For example, the 1756-L7x controllers have replaced the serial port with a higher performance USB port for uploading and downloading.
The Controller Properties dialog box displays controller configuration information for the open project and, when online, for the attached controller. The System Protocol tab allows you to configure the controller’s serial port for DF1 Master, DF1 Point to Point, DF1 Radio Modem, DF1 Slave, or DH485. The parameters present on this tab are dependent upon the protocol you select.
The ability to change the settings on this tab can be controlled by
FactoryTalk Security
 permissions.
TIP:
If you wish to configure your system for ASCII, click the User Protocol tab.
Parameters
The parameters present on this tab are dependent upon the protocol you select.
Common Parameters
Protocol
Choose the Protocol from the menu. Choose from DF1 Master, DF1 Point to Point (default), DF1 Radio Modem, DF1 Slave, or DH485.
Station Address
Enter the current station address for the serial port to which the DF1 protocol is now associated. Valid values are in the range of 0...254; the default value is 0.
Error Detection
Click one of the radio buttons to specify the error detection scheme used for all messages.
  • BCC - the processor sends and accepts messages that end with a BCC byte.
  • CRC - the processor sends and accepts messages with a 2-byte CRC.
Enable Duplicate Detection
Select this box to enable duplicate message detection, which causes the protocol to ignore all duplicate messages. This option is unavailable by default.
DF1 Master Parameters
Transmit Retries
Enter the number of attempted transmits without getting an acknowledgment before a message is deemed undeliverable. Valid values are in the range of 0...255; the default value is 3.
ACK Timeout
Enter the time the object waits for an acknowledgment to a message transmission. Valid values are in the range of 0...65,535, in 20 ms increments; the default value is 50 (that is, 50*20 ms, or 1000 ms, or 1 second).
Reply Message Wait
Enter the time (in ms) that the master will wait after receiving an acknowledgment to a master-initiated message before polling the slave for a reply. Specify this time in 20 ms increments; the default value is 50 (that is, 50*20 ms, or 1000 ms, or 1 second).
Polling Mode
Choose a polling mode from the menu. Choose from:
  • Message Based - Do not allow the slave to initiate messages.
  • Message Based - Allow the slave to initiate messages.
  • Standard - Multiple message transfers per node scan.
  • Standard - Single message transfer per node scan.
The default mode is Message Based, allowing a slave to initiate messages.
Master Transmit
Choose the master message transmit that designates when to send any DF1 master message. Choose from:
  • Between Station Polls - The master transmits a message before the next station.
  • In Poll Sequence - The master transmits messages only when the station number is encountered in the poll list.
The default is Between Station Polls.
Normal Poll Node Tag
Choose the tag name of the structure that contains the normal poll node list. Use the Tag Browser to select the appropriate tag name.
The default tag is <none>.
Normal Poll Group Size
Enter the total number of active stations polled from the poll node list. Valid values are in the rage of 0...255; the default value is 0.
Priority Poll Node Tag
Choose the tag name of the structure to store the priority poll node list. Use the Tag Browser to select the appropriate tag name.
The default tag is <none>.
Active Station Tag
Choose the tag name of the structure to store the status (active or non-active) of each node. Use the Tag Browser to select the appropriate tag name.
The default tag is <none>.
DF1 Point to Point Parameters
NAK Receive Limit
Enter the number of NAKs the processor can receive in response to a message before stopping the transmission. Valid values are in the range of 0...255; the default value is 3.
ENQ Transmit Limit
In the ENQ Transmit Limit field, enter the number of inquiries this controller sends to the target of our message after getting an internal ACK timeout. This controller did not see an ACK from the target controller so we are going give it another chance (send ENQ) to reply before a full retransmit of the original message.
Valid values are in the range of 0...127.
ACK Timeout
Enter the time the protocol waits for an acknowledgment to a message transmission. Valid values are in the range of 0...65,535, in 20 ms increments; the default value is 50 ms (that is, 50*20 ms, or 1000 ms, or 1 second).
Embedded Responses
From the Embedded Responses menu, choose one of the following.
  • Enabled - If the controller is in the middle of transmitting a message and it simultaneously receives a complete message, it can ACK or NAK the newly received message directly inside the one it is currently sending. Thus, there is no need for a separate message containing the ACK/NAK.
  • Autodetect - All Logix controllers are able to recognize an incoming embedded message. Once a received embedded message is detected, this controller lets itself transmit embedded responses. This receiving controller behaves the same as having the Embedded Response field set to Enabled.
This functionally can help cut down on message traffic. The embedded messaging scheme only works when in Full Duplex (must be able to send and receive at the same time). At least one controller must have Embedded Responses ENABLED to invoke this functionality.
DF1 Radio Modem Parameters
Enable Store and Forward
Select this box if you want to use the Store and Forward feature. By default, this box is cleared. When enabled, the destination address of any received message is compared to the Store and Forward tag table. If there is a match, the message is then forwarded (re-broadcast) out the port.
Store and Forward Tag
Enter the name of the controller-scoped tag which contains the Store and Forward table.
Each bit represents a station address. If this controller reads a message destined for a station that has its bit set in this table, it forwards the message.
TIP:
For broadcast messages, the last bit of the Store and Forward tag must be set to 1 (array 15, bit 15).
DF1 Slave Parameters
Transmit Retries
Enter the number of attempted transmits without getting an acknowledgment before a message is deemed undeliverable. Valid values are in the range of 0...255; the default value is 3.
Slave Poll Timeout
Enter the amount of time that the master will wait for an acknowledgment to a message sent to the slave.
EOT Suppression
Select the EOT Suppression box if you want to suppress the transmission of the EOT symbol at the end of a slave message.
DH485 Parameters
Max Station Address
In the Max Station Address field, enter the largest node address on a DH485 network.
Valid values are in the range of 0...31; the default value is 31.
Token Hold Factor
In the Token Hold Factor field, enter the maximum number of messages a node can transmit on a DH485 network for the time it has the token.
Valid values are in the range of 1...4; the default value is 1.
OK
Click this button to accept your edits and close the Controller Properties dialog box.
Cancel
Click this button to cancel your edits.
Apply
Click this button to apply your edits and continue editing in the Controller Properties dialog box.
Help
Click this button for help on the System Protocol tab.
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