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.).
The lower part of the terminal command decoder shows the control in which only digital
inputs of all control signals are enabled even if link operation command LE has been
turned ON.
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