TOHO ELECTRONICS TTM-00BT - Manual (Page 26)

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7.9.10 Communications precautions
1) Communications timing
Set a sufficient response delay to make sure that this product is switched over from
transmission to reception with regard to a high-level computer in using communications.
See "7.9.3 Communications procedure" and "7.9.2 3) Setting a response delay."
2) Interval between requests
In transmitting a series of "request messages" from a high-level computer, allow for an interval
of 1msec or more from the reception of a "response message" from this product to a next
transmission.
3) Response conditions
This product will not return a "response message" unless it receives a "request message"
containing an STX and ETX (BCC).
If, therefore, the "request message" is error-ridden, this product will not return a "response
message" (error reply) containing a NAK and ERR unless the conditions mentioned above are
met.
Therefore, the high-level computer transmits the necessary "request message" again if a
"request message" is sent to this product but the latter does not return a "response message" at
the end of an appropriate period.
The moment this product receives an STX, it clears all codes received before that.
4) Errors in unit number specification
This product will not respond to any "request message" that specifies a unit number other than
that specified for itself. If, therefore, the a unit number portion of a "request message" is
error-ridden, none of the mobile units will return a "response message."
Therefore, the high-level computer transmits the necessary "request message" again if a
"request message" is sent to this product but the latter does not return a "response message" at
the end of an appropriate period.
The moment this product receives an STX, it clears all codes received before that.
5) Number of digits in data and the decimal position
See "7.9.9 Code description, ⑥ Numerical data."
6) Operation after receiving a store request message
This product starts to store data after correctly receiving a store request message from a
high-level computer.
This product only stores data different from the contents of the EEPROM (data that is
changed). The time (TW) required for storing data is within 2 seconds.
This product transmits a storage-complete reply (ACK) when the data is stored.
This product will not guarantee that the data is stored if this product is turned off during a
storage operation. Do not turn off this product for 2 seconds after transmitting a store request
message.
7) Operation after turning on the power
This product will not perform communications (no response) for about 3 to 5 seconds after it is
turned on. Allow for a delay until communications is started after this product is turned on.