6. Function blocks
6.1 Manufacturer function blocks
Other
Signal diagram
QN
EC
E1
RY
BY
t ≦ t response max t > t response max
t ≦ t response max
T_
EN
QV
A B C
Fig. 241: Signal diagram of frequency counter
EN: Activates the function block
T_: Trigger input; the function code is sent to the Modbus TCP server when there is a rising edge at T_.
BY: Busy; indicates waiting for the server response and switches to a state of 0 when time t
response
elapses.
RY: Ready; the request has been sent and the Modbus TCP client has received a response. RY=0 if EN=0
E1: Error; server rejection or formal error
QV: Actual number of elements
QN: Only for FC23: Actual number of elements in 2nd request
EC: Errorcode value
A: Normal operation; the server responds within specified time t
response
B: Fault scenario; the server does not respond within the specified time t
response
, potentially because
the cable has been disconnected.
C: Fault scenario; the server is sending an exception code, or wrong port selected, etc.
Retention
The function block does not recognize retentive data.
Example FC23
Keep the 0-based address system in mind.
If the address range does not match the Modbus server's address range
because the former starts from 0 and the latter from 1, you will need to
use an offset.
In this case, you will need to set the start address to the original value
minus 1.
Alternatively, the option Auto-decrement on all addresses can be
activated with a checkmark.
The following parameter configuration for the MC function block does the following:
easyE402/24 MN050009ENEaton.com
531
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