38003
Local supply voltage (8
–40 Vdc) as a floating point
Expansion I/O
115S Serial Expansion I/O modules can be added to provide additional I/O. When adding expansion I/O modules to
the WI-MOD-xxx-E-5W , the appropriate serial port must be configured as
“Expansion I/O.” The default serial
parameters of the port should be 9600, N, 8, 1, which matches the defaults of the 115S Serial Expansion modules.
These parameters can be changed to increase poll speeds in larger systems. However, the 115S serial port and the
WI-MOD-xxx-E-5W serial
port need to match. If more than three serial expansion modules are added, the Maximum Units to Poll field on the
Serial page will also need to be adjusted (see
“4.7 Serial Configuration” on page 35).
Connect the serial expansion module and make a note of the address (rotary switches on the bottom) because
this address will be used as an offset to locate the I/O within the WI-MOD-xxx-E-5W . Make sure that the devices
at either end of the RS-485 cable have the termination switch enabled (on)
—this includes the WI-MOD-xxx-E-5W.
Failure to terminate the RS-485 correctly could result in the modules not operating correctly.
115S Expansion I/O Memory Map
Input/output data on the 115S module is read into memory locations according to their Modbus address. The
maximum number of Modbus addresses is 24. Each 115S module has an offset that applies to the location of its
registers. This offset is equal to the units Modbus address (selected on the rotary switch on the end of the 115S
expansion I/O module), multiplied by 20.
For example, if connecting a WI-EX-IO-11 (16 x DIO) with address #15:
•
Digital input 1 will be at register location 10301 ((15*20) +10001)
•
Digital Output 1 will be at register location 301 ((15*20) +1)
If using a WI-EX-IO-12 (8 x DIO & 8 AIN) with address 16:
•
Digital input 1 will be at register location 10321 ((16*20) +10001)
•
Analog input 1 will be at register location 30321 ((16*20) +30001)
See Appendix D for a more detailed address map of the serial expansion I/O modules.
When adding expansion I/O modules to the WI-MOD-xxx-E-5W , there are two built-in registers used to
indicating the communication status of the module.
•
Communication Fail
—This register is located at register location 10019 + offset value. It will indicate “1”when
the module is in failure.
•
Communication OK
—This register is located at register location 10020 + offset value. It will indicate “1”when
the module is communicating OK.
Fail-safe Blocks
Fail-safe block configuration allows the internal registers to be set to a pre-configured value on startup, as well as
configuring the DIO to reset to a predefined value after a timeout period has elapsed. In addition, if a remote device
is sending I/O to the local DIO and it is in
“communications fail,” the output can set to the configured fail value after
a pre-configured time.
In Figure 69, register 40501 holds an analog value that is being updated from another module every 60 seconds. The
module is configured so that on startup the value 16384 will be written into register 40501, and then it will start
counting down the timeout period (in this case, 130 seconds), which is a little over two times the one-minute update
period from the sending module. After 130 seconds, if the module still has not received an update from the other
module, register 40501 will be set to the fail value (in this case, 0).
If the
“Invalidate on Fail” option is selected, the value is set to a null or invalidated value (~). See “Invalid Register
State” on page 64. If this register is mapped to another module and the state is “Invalidated” the mapping will
be inhibited from sending until the invalid value is updated with a real value. In addition, if the register is being read
by a Modbus master or client, an exception response will be returned because the register is invalid. If a Modbus
master or client is writing from a register with an invalid state to another device, the message will not be sent. The
maximum number of fail-safe blocks is 50.
