CN3800 Series
Protocol Manual for RS232C / RS422A
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CONTENTS |
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[1] Introduction |
… 3 |
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[2] Specifications |
… 4 |
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[3] Connection |
… 5 |
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1. |
RS232C |
… 5 |
2. |
RS422A |
… 6 |
[4] Setting Requirements for Communication |
… 7 |
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1. Communication Parameter Setting |
… 7 |
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2. Operation Mode Setting |
… 8 |
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[5] Communication Check |
… 10 |
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1. |
Preparation |
… 10 |
2. |
Circuit Check |
… 10 |
3. |
Poor Connection |
… 11 |
[6] Establishment and Abandonment of Data Link |
… 12 |
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1. |
Establishment of Data Link |
… 12 |
2. |
Abandonment of Data Link |
… 13 |
[7] Communication Format |
… 13 |
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1. |
READ Command Format |
… 13 |
2. |
WRITE Command Format |
… 14 |
3. |
Control Codes |
… 14 |
4. |
Check Code |
… 14 |
5. |
Positive Acknowledgment and Negative Acknowledgment |
… 15 |
6. |
Time Out, Etc. |
… 16 |
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[8] Details of Communication Commands |
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… 17 |
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1. |
Common Specifications |
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… 17 |
2. |
Operation Mode Related Commands |
[01] |
… 27 |
3. |
Display (LED) Related Commands |
[D1~D4] |
… 28 |
4. |
Monitor Screen Related Commands |
[M1~M3] |
… 30 |
5. |
Execution Parameter Screen Related Commands |
[E1~E5] |
… 32 |
6. |
Program Data Screen Related Commands |
[P1, S1~S6] |
… 34 |
7. Control Data Screen Related Commands |
[C1~C3] |
… 37 |
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8. |
KEY Lock Screen Related Commands |
[K1~K3] |
… 38 |
9. |
Initial Data Screen Related Commands |
[I1~I9] |
… 39 |
[9] Appendices |
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… 45 |
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1. |
ASCII Code Table |
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… 45 |
2. |
Circuit Check Sample Program |
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… 46 |
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[1] Introduction
The operating instructions in this copy describe the communication interface which is an optional function prepared for the Program Controller CN3800 Series. For the functions and features of the controller unit itself, refer to the Operating Instructions of the controller unit.
Two types of communication interfaces, RS232C and RS422A, are available. By using the types of signals conforming to the specifications of EIA RS232C or RS422A, various types of data can be set or read from the CN3800 Series by personal computer, etc.
(Note: With the initial data screens, data can only be read but cannot be set or changed. Data setting and changing are to be done by the LOC mode (front key).)
RS232C and RS422A are data communication standards specified by the U.S. Electronic Industries Association (EIA). The Japanese standard corresponding to these standards is JIS X5l01 (Old JIS C6361). This standard covers the electrical and mechanical points; in other words, it refers to only the hardware. It does not touch upon the software aspect of data transmission
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procedures. Therefore, communication cannot be carried out unconditionally by a device equipped with this interface. Users are required to be fully informed, in advance, of the specifications and transmission procedures.
The use of RS422A allows parallel connection of multiple CN3800 Series Controllers (including the Digital Controller SR25 Series). At present, only a few personal computers can support this interface. However, the use of a line converter for FS232C/PS422A conversion solves the problem.
[2] Specifications
Signal level: |
Conforming to EIA RS232C/RS422A |
Communication mode: |
RS232C 3-wire half duplex |
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RS422A 4—wire half duplex multidrop |
Synchronization system: |
Start—stop synchronization |
Communication distance: |
RS232C l5m |
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RS422A 1.2km |
Transmission speed: |
1200, 2400, 4800 bps |
Transmission procedure: |
Non-procedural |
Data format: |
Data length 7 bits, even parity, stop bit 1 |
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or |
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data length 8 bits, no parity, stop bit 1. |
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BOC: |
Checksum 1 byte |
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Communication codes: |
ASCII codes |
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Control codes: |
Not used. |
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Number of connectable units: RS232C |
1 unit |
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RS422A |
10 units |
[3]Connection
1.RS232C
Example 1
Host computer |
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CN3800 |
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(1) |
Ground |
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Ground (1) |
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(2) |
SD |
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RD |
(3) |
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(3) |
RD |
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SD |
(2) |
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(7) |
SG |
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SG |
(7) |
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(4) |
RS |
> |
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(5) |
CS |
< |
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(20) ER |
> |
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(6) |
DR |
< |
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Example 2
Host computer |
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CN3800 |
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Shield |
(1) |
SD |
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RD (3) |
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RD |
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SD |
(2) |
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SG |
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SG |
(7) |
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RS |
>----- |
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DR |
<----- |
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CD |
<----- |
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ER |
<----- |
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CS |
<----- |
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2. RS422A
Example 1
Host computer |
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CN3800 |
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Shield |
(1) |
GDA |
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RDA |
(4) |
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SDB |
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RDB |
(6) |
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RDA |
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SDA |
(3) |
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RDB |
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SDB |
(9) |
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SG |
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SG |
(5) |
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Note: The figures in ( ) are Pin Nos.
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*Return of the control signals shall be executed in accordance with the respective host computer specifications.
Connector Pin Positions
[4]Setting Requirements for Communication
1.Communication Parameter Setting
The following communication parameters shall be set by displaying the Communication Option Screen of the initial data screen. (Parameter setup or parameter alteration is not possible, though monitoring is possible, unless the operation mode is set at “LOC” and the action mode is at “RST” or “MAN” at the same time.)
(1)ADDR (Address <Machine No.>) Setting
Designate any number from 0 to 31. If multiple units are used, designate different addresses for the various units. Be sure not to designate the same number to more than one unit.
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(2)BPS (transmission speed) setting
Designate any level from 1200, 2400, and 4800 bps to meet the transmission speed of the host computer. If multiple units are used, set them all at the same speed.
(3)DATA (Data bit length, parity) setting
Select the data bit length, parity, stop bit length from the following, to be set in conformity with the host computer.
0:Data 7 bits, even parity, stop bit 1
1:Data 8 bits, no parity, stop bit 1
If multiple units are used, set them all with the same values.
2. Operation Mode Setting
Three types of CN3800 operation modes, as shown below, are available. Each mode has a different communication condition.
1.LOC mode (Data setting is executed by operating front keys.)
2.EXT mode (Data setting is executed by external control input “DI”.)
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3. COM mode (Data setting is executed through communication system.)
[COM-EXT mode (Data setting is executed by external control input during COM mode) ]
(1)During LOC or EXT mode, a data link can be established. However, [D1 ~ D4] READ commands only are valid during COM mode and the error message “ERO” + NAK is returned when any other command is delivered.
(2)During COM (COM-EXT) mode, all READ and WRITE commands are valid.
(3)To alter the operation mode, display the LCD operation mode screen and select/set LOC, EXT or COM as required. Select for the operation of CN3800 by means of the communication system.
*Refer to the Operating Instructions of the CN 3800 unit.
(4) If the input type, range, unit, or scaling is changed, or memory initialization (1,2) is executed on any of the initial data screens during LOC mode, the CN3800 controller automatically suspends the communication and abandons the data link, to enter Link-OFF status. Carry out data link establishment again after a lapse of 500 msec.
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[5] Communication Check
1.Preparation
(1)Connection
Referring to section [3] above, connect CN3800 to the host computer or the line converter.
(2)CN3800 side preparation ADDR (Address): 0 BPS (speed): 1200 bps
DATA (Data bit length): 7 bits, even parity
In addition to the above, change the operation mode from LOC to COM mode.
(3)Host computer side preparation
The setting contents shall be the same as the CN3800 side.
2. Circuit Check
Install the sample program presented at the end of these instructions in the host computer, and run the program. This program is a sample prepared for NEC PC-9801 Disk Basic N88-BASIC (86). If
using another model, OS, or language, the user must prepare an equivalent program.
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When the program is run and the following display is given, the circuit connection can be judged
as correctly arranged. The values represent PV value, SV value, PTN no., STP no., as in the sequence.
00
Dl 23.5, -- ,l, l
OK
The PV value above changes with measuring range, measuring temperature, or other condition.
3. Poor Connection
If the above circuit check does not operate normally, check again for poor connection with the host computer, faulty setup, or the program itself. In particular, it should be noted that the wiring specification for the return line of the control signal wire on the host computer side differs from one type of host computer to another.
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[6] Establishment and Abandonment of Data Link
If a data link is not yet established CN3800 does not process or return the data even if receiving a READ command or WRITE command. Never fail to send out command(s) after establishing the data link.
1. Establishment of Data Link
Master station (Host) |
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Slave station CN3 800 |
ECT + “ADDR” + ENQ |
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“ADDR” + ACK (Normal) |
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No response (Abnormal) |
In the case of “ADDR (Address) No. = 10”, four bytes of 04H + 31H + 30H + 05H are transmitted.
(EOT) (1) (0) (ENQ)
(l) CN3800 with the data link established by ECT is linked off.
(2)With a normal response given, reading or changing of the CN 3800 data by the READ command and WRITE command can be executed.
(3)The two-digit no. 0031 set on CN3800 side shall be designated to the address no. (“ADDR”).
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(4)There is no response from CN3800 if there exists no CN3800 with the specified address no. or if no normal receive operation is performed.
2. Abandonment of Data Link |
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Master station (Host) |
Slave station CN3800 |
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EOT |
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No response |
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(1)Transmission of ECT links off the CN3800 with data link established.
[7]Communication Format
1.READ Command Format
The READ command reads the data, status, etc., of CN3800 |
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Master station (Host) |
Slave station CN3800 |
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STX + “TEXT” + ETX + BCC |
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(Data Request) |
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“ER*” + NAK (Abnormal) |
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(Abnormal) |
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STX + “TEXT” + ETX + |
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BCC (Normal) |
NAK |
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------------- (Max. 3 times) |
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