4.4 Terminal Command Decoders
4-9
Chap. 4 BLOCK DIAGRAMS FOR CONTROL LOGIC
Programmable digital input terminals [X1], [X2], [X3], [FWD] and [REV] can be assigned to internal terminal
commands such as (FWD) or (REV) decoded by data settings of related function codes as shown in the block
diagrams in Figures 4.3 (a) through 4.3 (d). In the decoders, negative logic input signals are also applicable if you
set data of 1000s to the function code.
The contents of the block diagram are divided into five groups, depending on whether inputs are assigned for the
same internal terminal commands respectively or the commands issued from the communications facility (linked
operation) specify the internal commands. Each of the diagrams shown in Figure 4.3 has following role.
- Figure 4.3 (a) The terminal command decoder (general) shows the decoding process of the internal
commands functioning with the negative logic inputs. This is switchable with inputs from the
communications facility (for example, link operation commands received through RS-485
communications).
- Figure 4.3 (b) The terminal command decoder (terminal signal inputs) shows the process to decode internal
terminal commands dedicated to the control signal input applied to the inverter's terminal
block. These commands cannot be changed via the communications facility (link operation
command).
- Figure 4.3 (c) The terminal command decoder (terminal signal input excluding negative logic) shows
process to produce (FWD) and (REV) commands. In this process, settings via the
communications facility do not take effect. In the next process of the drive command
generator, however, they may take effect. (Refer to the block diagram in Section 4.3, "Drive
Command Generator.") To keep the inverter operation safe, any negative logic input for the
(FWD) and (REV) commands cannot be applied.
- Figure 4.3 (d) The upper part of the terminal command decoder (ORing with link commands/ignoring link
commands) shows the process to produce commands by ORing signals issued from the
communications facility and the control signal input terminal block (Logical Oring. If any of
input signals is ON, then the command becomes ON.).
- Figure 4.3 (d) The lower part of the terminal command decoder (ORing with link commands/ignoring link
commands) shows the process to produce commands by forcing the inverter to ignore signals
issued from the communications facility even if link operation ((LE): link operation
command) has been turned ON.
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