TOHO ELECTRONICS TTX-700 - Manual (Page 24)

e) CRC-16
This error check code is for detecting message errors. This transmits a CRC-16 (tour
redundancy code).
The multinomial for generating a CRC-16 used in this product is X
16
+X
15
+X
2
+1.
To learn how to calculate the CRC-16, see "6.7. Example of CRC-16 calculations."
To affix an error code at the end of the message, affix the low-level byte first, then the
high-level byte of the CRC.
f) Number of data
This specifies the number of registers to be read and written x 2. Since the number of
registered in this product is fixed at 2, specify 04H here.
g) Data portion
This specifies data to be written in the register. The data is fixed at 4 bytes. This product
will write data without the decimal point.
Example: In the case of numerical data
Example Significance of the value
Proportional band (P) = 1.0 % 0 0 0 0 0 0 0 A H
PV = 1200.0
°
C 0 0 0 0 2 E E 0 H
SV = -10.00
°
C F F F F F C 1 8 H
In the case of text data, write the ASCII code "□INP" (□ is a space): 2049E50H.
h) Error code
If a message from a high-level computer is error-ridden, it will be incorporated in the
"response message" from this product and returned.
The error number "04" is an instrument error (memory error or A/D conversion error, AT
error). It will be incorporated in the "response message" regardless of whether there is an
error in the "request message."
If there are two or more errors occurring at the same time, the largest error number will be
incorporated.
The table below indicates the error contents and classifications.
Error No. Error contents in the "request message" received by this product
01 Received an unsupported function code.
02 Received an address other than the specified one.
03 The numerical data deviated from the "range of settings designated specifically with
setting items."
04 Instrument error (memory error or A/D conversion error, AT error)
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