BASEstartm Classic DAS
for Modicon®
Programmable Controllers
Installation and User's Guide


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2.3 Postinstallation Tasks

This section describes the tasks to perform after installing the DAS for Modicon programmable controllers, including editing the configuration file, setting the BASEstar Classic DCM support block parameter, configuring ports, addressing a Modbus Plus or TCP/IP node, setting unsolicited parameters and setting up plant-floor equipment.

2.3.1 Editing the Configuration File

A configuration file template, BCC$SYSDATA:DCM_MOD_CONFIG.TEMPLATE, is supplied with the DAS kit. The configuration file contains definitions for types, paths, and devices. A type record represents a protocol emulator (PE). A path record represents a network interface (NI). Copy the template file, edit the file to include site-specific information about types and paths, and execute the file.

The following sections give examples of the type, path, device records. Refer to the BASEstar Classic Command Line Interface User's Guide for more information about creating type, path, and device definitions.

2.3.1.1 Editing Type Records

The following example shows the type records created by the configuration file:


create type MOD_584_TYPE/manufacturer="Modicon"/model=584 - 
  /protocol=MOD584/description="Modicon 584"/LOG 
 
create type MOD_984_TYPE/manufacturer="Modicon"/model=984 - 
  /protocol=MOD984/description="Modicon 984"/LOG 
 
create type MOD_HOST_TYPE/manufacturer="Modicon"/model=984 - 
  /protocol=MODHOST/description="Modicon 984"/LOG 

The /protocol fields identifies the PE to use in communicating to the device, so this field cannot be changed. The MODHOST protocol is used only with Modbus-Plus devices. The model and manufacturer fields are ignored by this DAS, so they can be any value valid to Device Connection Management.

2.3.1.2 Editing Path Records

The following example shows the path records created by the configuration file:


create path MODBUS_PATH /vaxport=LTAXXX:/netname=MODBUS - 
  /multidrop/io_size=512/retries=2 - 
  /line=(mode=rtu,type_ahead,speed=9600,data=8,stop=1)/LOG 
modify path MODBUS_PATH/line=(parity=even,full,hangup)/LOG 
 
create path MPLUS_PATH /vaxport=MPA1:/netname=MPLUS - 
  /multidrop/LOG 
 
create path MODTCP_PATH /vaxport=UCX$DEVICE:/netname=MODTCP - 
  /multidrop/LOG 

Devices using Modbus communications should use the MODBUS path. Devices using Modbus-Plus communications should use the MPLUS path. Devices using Modbus TCP/IP communications should use the MODTCP path.

If using the Modbus path, the /vaxport field refers to the port (either LAT or TT) that is connected to the Modbus line (either directly or through a modem). If a direct connection to the device is made, then the path can be set as POINT_TO_POINT . If the connection is to a Modbus network with more than one device configured, then the path must be set as MULTIDROP . The /netname field identifies the NI that is being used to communicate with the device.

Table 2-4 lists the path parameters for a Modbus connection and indicates the value(s) that are allowed for each.

Table 2-4 Modbus Path Parameters
Parameter Value(s)
VAXport 1 LTAXXX:, TTXX:
Netname MODBUS
Multidrop MULTIDROP, POINT_TO_POINT
Timeout 2 1-15
Retries 1-5
IO Size 3  


1This parameter should be set to the OpenVMS device name used to connect to the Modbus network or device.
2The timeout defaults to 9 seconds if no timeout is specified.
3The IO_SIZE parameter is ignored by this DAS.

Table 2-5 lists the line parameters and indicates the value(s) that are allowed for each. If only one value is allowed, then the DAS will generate an error if the user sets the parameter to anything other than the allowed value. Verify that the VAXport and the line parameters match your plant-floor configuration.

Table 2-5 Modbus Line Parameters
Parameter Value(s)
Stop Bits 1
Data Bits 7-8
Parity even, odd, none
Speed 110-19200
Full Duplex full
Mode rtu,ascii
Echo noecho
Host Synch hostsync, nohostsync
TT Synch ttsync, nottsync
Typeahead type_ahead
Hangup hangup
Modem modem, nomodem
Dialup dialup, nodialup
Disconnect disconnect, nodisconnect

If using the Modbus-Plus path, the /vaxport field refers to the OpenVMS device that implements communications to the Modbus-Plus network (MPA1-MPA4). Up to four Modbus-Plus communications cards are allowed on one system. On Alpha systems, the name of the OpenVMS dvice can be JPA1-JPA4 due to a conflict in device names on some OpenVMS systems. The path must be set as MULTIDROP since Modbus-Plus is a multidrop network. The /netname field identifies the NI that is being used to communicate with the device.

Table 2-6 lists the path parameters for a Modbus-Plus connection and indicates the value(s) that are allowed for each.

Table 2-6 Modbus-Plus Path Parameters
Parameter Value(s)
VAXport 1 MPA1-MPA4, JPA1-JPA4
Netname MPLUS
Multidrop MULTIDROP
Timeout 2 1-15
Retries 3  
IO Size 4  


1This parameter should be set to the OpenVMS device name used to connect to the Modbus-Plus network. JPA1-JPA4 are used only on some OpenVMS Alpha versions where there is a conflict with the MPA1-MPA4 device names.
2The timeout defaults to 9 seconds if no timeout is specified.
3The parameter is ignored by this DAS. The DAS does not do retries.
4The IO_SIZE parameter is ignored by this DAS.

If using the Modbus TCP/IP path, the /vaxport field refers to the logical name that points to the OpenVMS internet pseudodevice that implements communications to the TCP/IP network. UCX$DEVICE is used on systems that have UCX installed. TCPIP$DEVICE may be used on systems that have the newer TCPIP interface installed. The path must be set as MULTIDROP , since there is only one pseudodevice defined, even though all connections are point-to-point connections. The /netname field identifies the NI that is being used to communicate with the device.

Table 2-7 lists the path parameters for a Modbus TCP/IP connection and indicates the value(s) that are allowed for each.

Table 2-7 Modbus TCP/IP Path Parameters
Parameter Value(s)
VAXport 1 UCX$DEVICE
TCPIP$DEVICE
Netname MODTCP
Multidrop MULTIDROP
Timeout 2 1-15
Retries 3  
IO Size 4  


1UCX$DEVICE is used on systems that have UCX installed. TCPIP$DEVICE may be used on systems that have the newer TCPIP interface installed.
2The timeout defaults to 9 seconds if no timeout is specified.
3The parameter is ignored by this DAS. The DAS does not do retries.
4The IO_SIZE parameter is ignored by this DAS.

2.3.1.3 Editing Device Records

The following example shows the device records created by the configuration file:


create device MOD_584 /type=MOD_584_TYPE - 
  /descrip="Modicon 584"/netaddress=YY - 
  /path=MODBUS_PATH/manuf="Modicon"/timeout=300/LOG 
 
create device MOD_984 /type=MOD_984_TYPE - 
  /descrip="Modicon 984"/netaddress=YY - 
  /path=MODBUS_PATH/manuf="Modicon"/timeout=400/LOG 
 
create device MPLUS_984 /type=MOD_984_TYPE - 
  /descrip="Modicon 984"/netaddress="YY-YY-YY-YY-YY" - 
  /path=MPLUS_PATH/manuf="Modicon"/timeout=400/unsolicited/LOG 
 
create device MHOST_984 /type=MOD_HOST_TYPE - 
  /descrip="Modicon 984"/netaddress="YY" - 
  /path=MPLUS_PATH/manuf="Modicon"/timeout=400/unsolicited/LOG 
 
create device MODTCP_984 /type=MOD_984_TYPE - 
  /descrip="Quantum TCP/IP"/netaddress="YY.YY.YY.YY" - 
  /path=MODTCP_PATH/manuf="Modicon"/timeout=400/unsolicited/LOG 

The timeout on the device definition controls the time that BASEstar Classic device connection management allows for a device operation to complete. The value for the device timeout should be larger than the expected time of the longest device operation and also larger than the timeout on the path definition. To control the timeout for individual I/O operations to the device, use the timeout on the path definition.

Unsolicited data collection is supported only for the Modbus-Plus and TCP/IP NIs, so the /unsolicited qualifier should be used only on devices with a Modbus-Plus or TCP/IP path.

The MODHOST PE is supported for use only with the Modbus-Plus NI and is used for unsolicited data collection. See Section 3.4.2 for more information.

2.3.1.4 Network Address Using Modbus

Modbus addresses are decimal numbers from 1-255.

2.3.1.5 Network Address Using Modbus Plus

Modbus Plus requires 5 bytes of routing information to address a particular node on the network. This method allows remote nodes to be addressed up to four networks away from the host. The range of node addresses on a single network is 1 ... 64. The format for the network address field within DCM is as follows:


xx-xx-xx-xx-xx 

Where xx is the routing address byte. All five bytes of routing information must be included in the network address field. A zero as a routing byte indicates that no further routing will occur. Once a zero is encountered as a routing address byte all of the remaining routing bytes must be zero.

2.3.1.6 Network Address for the Modbus Plus Host

When addressing the host node only one routing address byte is required. Specify the Modbus-Plus address of the host SQ-85/SA-85 card. Only one host device is allowed per Modbus-Plus card.

2.3.1.7 Network Address Using TCP/IP Ethernet Interface Module

To address a TCP/IP NOE module use the TCP/IP address of the ethernet interface of the module. The format for the network address field within DCM is as follows:


xx.xx.xx.xx 

Where xx is the routing sub-net byte. All four bytes of routing information must be included in the network address field. The DAS only supports sub-net routing format. Using a host name rather than a sub-net address is not supported.

For more information about maintaining type, path, and device definitions, refer to the BASEstar Classic Command Line Interface User's Guide.


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