To configure the processor as a slave station, place the processor in program mode and follow the steps below using your programming software:
Use Table 2.4. to help you understand the communication parameters you need to specify on the Channel Configuration screen.
Use Worksheet 2.3 (page D-7) for an example configuration and to record your station’s configuration.
1.Double-click on the Channel Configuration file to bring up the Edit Channel Properties interface.
2.On the Channel 0 tab, choose System (Slave) for your Communication Mode.
3.Configure the Serial Port parameters according to Table 2.4.
4.Configure the Options parameters according to Table 2.4.
5.When all parameters are set, click OK.
Table 2.4 Communication Parameters for a PLC-5 Slave Station. RSLogix 5 Tab Parameter Selections
Channel 0 Diagnostic File Select an unused integer file to store channel status information. You must define a diagnostic file in order to be able to view channel 0 status. See Table 2.5 on page 2-18 for a description of what this file contains.
Remote Mode Change Enable
Check enable remote mode change if you want to switch the configuration of the channel during runtime. Leave the parameter set at the default (unchecked) if you are not using this feature.
Mode Attention Character Select a character that will signal a remote mode change. Leave the parameter set at the default if you are not using remote mode change.
System Mode Character Select a character that will signal the channel to switch into system mode. Leave the parameter set at the default (unchecked) if you are not using remote mode change.
User Mode Character Select a character that will signal the channel to switch into user mode. Leave the parameter set at the default if you are not using remote mode change.
Serial Port Baud Rate Select a communication rate that all devices in your system support. Configure all devices in the system for the same communication rate.
Bits Per Character Match the number of bits per character to the devices with which you are communicating.
Stop Bits Match the number of stop bits to the devices with which you are communicating. Control Line This parameter defines the mode in which the slave station driver operates. Choose
a method appropriate for your system’s configuration:
• If you are not using a modem, choose NO HANDSHAKING.
• If the master modem is full duplex and transmits a constant carrier and the slave modem is half-duplex, choose HALF-DUPLEX MODEM WITH CONTINUOUS CARRIER.
• If all the modems in the system are half-duplex, choose HALF-DUPLEX MODEM WITHOUT CONTINUOUS CARRIER.
Parity Parity provides additional message packet error detection. To implement even parity checking, choose Even. To implement no parity checking, choose None.
Serial Port Error Detect With this selection, you choose how the processor checks the accuracy of each DF1 packet transmission.
BCC: This algorithm provides a medium level of data security. It cannot detect:
• transposition of bytes during transmission of a packet
• the insertion or deletion of data values of zero within a packet
CRC: This algorithm provides a higher level of data security.
Select an error detection method that all devices in your system support. When possible, choose CRC.
Options Station Address Define the octal address of the processor on the DF1 half-duplex link. Each station on a link must have a unique address. Choose an address between 0 and 3768. Station address 3778 is the broadcast address, which you cannot select as a station’s individual address.
DF1 Retries The number of times a slave station retries a message before the slave station declares the message undeliverable.
RTS Send Delay RTS send delay is the amount of time, in 20 millisecond increments, that elapses between the assertion of the RTS signal and the beginning of the message transmission. This time allows the modem to prepare to transmit the message. The CTS (Clear-to-Send) signal must be high for transmission to occur.
RTS Off Delay RTS off delay is the amount of time, in 20 millisecond increments, that elapses between the end of the message transmission and the de-assertion of the RTS signal. This time delay is a buffer to make sure that the modem has transmitted the message but should normally be left at zero.
ACK Timeout Define the amount of time, in 20 millisecond increments, that you want the processor to wait for an acknowledgment from the master station to its transmitted message.
Detect Duplicate Messages Duplicate packet detection lets the PLC-5 processor detect if it has received a message that is a duplicate of its most recent message from the master station. If you choose detect duplicate messages, the processor will acknowledge (ACK) the message but will not act on it since it has already performed the message’s task when it received the command from the first message.
If you want to detect duplicate packets and discard them, check this parameter. If you want to accept duplicate packets and execute them, leave this parameter unchecked.
MSG Application Timeout Define the number of 30 second increments within which the reply message must be received before the error bit is set on the message. The timer starts when the ACK is received.