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Chapter 11 Communication Specifications
11-3
11.3 Port 2
The specifications of port 2 are listed in Table 11.4. 1:n station communication by the high protocol is possible with port 2.
By creating and including a control procedure based on the high protocol on the personal computer which will become the
host, it becomes possible to control a maximum of 32 stations from one host. The systems can thus be configured in several
ways.
Table 11.4 Port 2 specifications
Item Specification
Dedicated (programming) port General purpose port
Communication speed 4800, 9600, 19.2 k, 38.4 k bps 300, 600, 1200, 2400, 4800, 9600, 19.2 k,
38.4 k, 57.6 k bps
Communication system Half duplex
Synchronization
Asynchronous
Startup system One-sided startup using the host side command
Transmission system Serial transmission (bit serial transmission)
Transmission code,
configuration
ASCII: 7-bit data, 1 start, 1 stop, even parity Configured by user
Transmission code outgoing
sequence
Sent out from the lowest bit in character units
Error control Vertical parity check, checksum, overrun check, framing check
Transmission unit Message unit (variable length)
Maximum message length 503 bytes (including control characters)
Note: 505 bytes when the station number is used.
1,024 bytes
Control procedure H-series dedicated procedure (h-protocol)
Standard protocol (transmission control procedure 1),
Simplified protocol (transmission control procedure 2)
Configured by user
Interface RS-422/485 (maximum cable length: 250 m)
Connector CPU side: 15-pin D-sub
Cable side: a cable equivalent to 17JE-23150-02(D8B) (DDK Co., Ltd.) is recommended (D-SUB
fitting screw M3 × 0.5)
(1) Setting port 2
Port 2 is configured by special register WRF03D. The settings can be changed even when port 2 is communicating. The
highest bit (b15) of WRF03D is setting bit.
If station number mode is used, make sure to set the station number from 0 to 31 in BCD code.
Value in WRF03D is saved in FLASH memory when writing flag (R7F6) is turned on. If saved in FLASH memory, it is
not necessary to set again at the next power up.
(Example) Transmission control procedure 2, communication speed 19.2 kbps, and station number 28.
Î WRF03D = HE228 After the setting is completed, WRF03D is changed to H6228. (b15 cleared)
Bit:
1514131211109876543210
WRF03D:
abc0 d e
Initial value:
0000000000000000
Figure 11.3 Special internal output for setting port 2
Field Setting value Content Note
a 0 Setting completed After the setting is completed, the
system changes this bit to 0.
1 Setting change request Set this bit to 1 when changing the
setting.
b 0 Transmission control procedure 1
1 Transmission control procedure 2
c 0 Without station number
1 With station number
d 0 Transmission speed 4800 bps Setting of bits 8 to 12 H0000
1 9600 bps H0001
2 19.2 kbps H0010
3 38.4 kbps H0011
Other than above 4800 bps
e 0 ~ 31 Station number * Set by BCD.
* Communication speed of general purpose port is configured in TRNS/RECV command. Value in WRF03D
is ignored.