ENGLISH 7/8
MI004640-E
Use of the network
To use the devices in the best way, mind that all RS485 buses headed by a Z-LINK1 must be
properly polarized and terminated.
Important points:
- Only for the Z-LINK1 configured in REMOTE I/O modality as master, the max number of
input/output that can be configured in the I/O repetition map:
* is 20, for digital inputs/outputs
* is 50, for analog inputs/outputs
- The Easy setup software allows to negate the status of digital outputs, compared with the
corresponding input; allows to scale the analog inputs, repeating the values in the
corresponding analog outputs. In both cases, it is possible to set the fail conditions.
- It is advisable to connect the (digital or analog) outputs in the Modbus master local bus
- At the first start, the master module checks which slaves belong to the network effectively.
For this reason: first, power on the Z-LINK1 «slave» devices; final, power on the Z-LINK1
«master» module
- In the Test Configuration window of Easy Setup software there is a incremental counter, to
display eventual fails in the modules connected and the radio communication quality. In
correspondence of each module of displayed I/O map, there is a flag that signals eventual I/O
fails in reading/writing.
After a time interval of about 1 minute, the timeout message on the slave devices actually
belonging to the network disappears, returning to the normal functioning.The behavior just
described can be observed if there is the absence of the Z-LINK1 device connected to the
interested Modbus slave device, too (for example, the previous Z-LINK1 connected to the Z-
4AI via local bus).
Infact
the Z-LINK1 devices can detect network paths with timing usually much higher
than the timeout of the Modbus Master.
Therefore, the PC (Modbus master) continuing to
poll, but the network is still employed to locate the device no longer connected. In particular,
the requests that arrive to the network when it is employed by another request will be
discarded, causing the subsequent failure on the slaves in the list (timeout temporary).
PC
(master)
Z-LINK1
(SW1-1
=on)
bus RS485
Z-4AI
Z-LINK1
(SW1-1
=off)
bus RS485
Z-8TC
Z-LINK1
(SW1-1
=off)
bus RS485
timeout
timeout
(temporary)
Missing of a slave device in a network of Z-LINK1
it is possible to observe a timeout message on all slave devices enquired (Z-8TC).
connected directly to a Z-LINK1 via local bus) during interrogation by the Modbus master,
via bus). If there is the absence of a Modbus slave device (for example, one Z-4AI
devices connected directly via bus and a PC as Modbus master (with a Z-LINK1 connected
Assume a system consisting of: a network of Z-LINK1 devices with some Modbus slave
