Txd (Transmit) - IDEC FC6A-C16K1CE Communications Manual

5: U C
SER OMMUNICATION

TXD (Transmit)

TXD S1
* *****
Valid Devices
Device
S1 (Source 1)
D1 (Destination 1)
D2 (Destination 2)
For valid device address ranges, see Chapter 2 "Device Addresses" in the "FC6A Series MicroSmart LAD Programming Manual".
*1 Internal relays M0 through M7997 or M10000 through M17497 can be designated as D1. Special internal relays cannot be designated as D1.
*2 Special data registers cannot be used.
Transmit data designated by device S1 can be a maximum of 1,536 bytes.
When transmission is complete, an output or internal relay, designated by device D1, is turned on.
Destination 2 occupies two consecutive data registers starting with the device designated by D2. The transmit status data register, D0000-D7998
and D10000-D55998, stores the status of transmission and error code. The next data register stores the byte count of transmitted data. The same
data registers cannot be used as transmit status registers for TXD1 through TXD3 instructions and receive status registers for RXD1 through RXD3
instructions.
The TXD instructions cannot be used in an interrupt program. If used, a user program execution error will result, turning on special internal relay
M8004 and the ERR LED on the FC6A Series MicroSmart. For details about the user program execution errors, see Chapter 3 "User Program
Execution Errors" in the "FC6A Series MicroSmart LAD Programming Manual".
Precautions for Programming TXD Instruction
• The FC6A Series MicroSmart has five formatting areas each for executing TXD1 through TXD3 instructions, so five instructions each of TXD1 through TXD3
can be processed at the same time. If inputs to more than five of the same TXD instructions are turned on at the same time, an error code is set to the
transmit status data register, designated by device D2, in the excessive TXD instructions that cannot be executed.
• If the input for a TXD instruction turns on on while another TXD instruction is executed, the subsequent TXD instruction is executed 2 scan times after the
preceding TXD instruction is completed.
• Since TXD instructions are executed in each scan while input is on, a pulse input from a SOTU or SOTD instruction should be used.
• The data register used to store the transmit/receive status and the transmit/receive data byte count must be different for the TXD instruction and the RXD
instruction.
• The TXD instruction cannot be used in an interrupt program. If used, a user program execution error occurs, the execution of the instruction is canceled,
and the next instruction is executed. For details about the user program execution errors, see Chapter 3 "User Program Execution Errors" in the "FC6A
Series MicroSmart LAD Programming Manual".
5-2
I
NSTRUCTIONS
D1 D2
***** *****
Function
Transmit data
Transmit completion output
Transmit status register
FC6A S M S A
ERIES ICRO MART
The transmit data is converted to the set data type and transmitted to the external
device using port 1 to 3.
I Q
— —
— X
— —
- -O T C
LL IN NE YPE OMMUNICATION
M R T C D Constant
— — — — X
*1
X — — — —
*2
— — — — X
M FC9Y-B1730
ANUAL
Repeat
X —
— —
— —