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(2) One-Byte Data
One-byte data in the text has a fixed length of one character
which is either 0 or 1. Seven items are covered, namely, stop
status, manual status, AT status, AH status, AL/HB status
and communication mode.
Stop (STBY), Manual (MAN), AT (ON), AH (ON),
AL/HB (ON), SB (ON), Communication (when the
remote mode is on).
Execution (EXEC), Auto (AUTO), AT (OFF), AH
(OFF), AL/HB (OFF), SB (OFF), Communication
(when the local mode is on).
(3) Special Data
Special data is data sent in response to numerical data which
are outside of the ordinary range. Their patterns are shown
in the following.
Numerical data is +10000~+10999.
Numerical data exceeds the indicated range.
Numerical data is over the scale.
CT temperature exceeded the higher limit value or fell
below the lower limit value in the case of thermocouple
input.
Wire breaking detected in the case of R.T.D. input
CT input value exceeded the higher limit value or fell
below the lower limit value.
Control output either turned on or turned off while CT
input measurement was ongoing.
Data is undeterminable due to a set value of alarm code,
P=OFF, or some other reasons.
• Data in the case where the alarm code is 0 and D2
(AH, AL) or D3 (CT, HB) command has been
received.
• Data in the case where the alarm code is 1~4 and D3
(CT, HB) command has been received.
• AL data in the case where the alarm code is 5~8 and
D2 (AH, AL) command has been received.
• I, D, SF or MR data in the case where P=OFF and D5
(P, I, D, SF, MR) command has been received.
7-5-3. Communication error
When an error is found in the block after receiving data from the
host, an error message is sent back. The format of error messages
and the types of errors are described in the following.
Error Message Format
Error Types
7-5-4. Non-response process
When an error is found in the block upon receiving data
transmitted from the host, the next correct data block is waited for
without transmission of response data. Therefore, the host has to
retransmit the command block in any of the following cases:
The start character was not @ (40H).
The communication No. did not match.
The end character was not CR (0DH).
A hardware error such as a framing error, overrun or a
parity error occurred.
7-5-5. Restrictions by commands, etc.
(1) Restrictions by Read Command
Upon receiving the D1 read command, the status of
unequipped options (AH, AL/HB, SB) become 0 (30H).
(2) Restrictions by Write Command
In the case of P=OFF and Y and P output, write data of
E2 (write command of manual output value) is either of
the following two. Otherwise, ER09 is sent back.
In the case of P=OFF and V and I output, a lower limit
output limiter value or a higher limit output limiter
value is to be set.
If a write command is invalid due to the local mode, a set
value of keylock, AT or some other conditions, and that
command is received, ER11 should be sent back. The
following cases also require ER11 to be sent back.
