Denso BHT-7500S User Manual

Also see for BHT-7500: Manual 

Contents

Denso BHT-7500S User Manual Manual pdf 149 page image

129Chapter 3. Communications Operations of the BHT3.4 Basic Communications Specifica-tions and Parameters3.4.1 Basic Communications SpecificationsListed below are the communications specifications when the BHT exchanges datawith a host computer through the CU-7000 (optical interface) or direct-connect inter-face cable.Direct-connect InterfaceSynchronizationTransmission SpeedTransmission CodeTransmission Bit OrderVertical ParityJIS 8-bit codesOptical Interface2400, 9600, 19200, 38400,57600, or 115200 bps■ SynchronizationFor accurate data transaction, it is very important to synchronize the transmissionbetween the sender and receiver. To do this, it is required to previously define thebit order and position, the character length, and the beginning and end of thecharacter to be transmitted.The start-stop synchronization is an asynchronous system which synchronizeseach character as a unit; that is, it externally adds start and stop bits to the leadingand trailing bit positions of the character to be transmitted, respectively. A clockstarts counting on receiving the start bit and it falls into a non-communication stateon receiving the stop bit. The number of the stop bits is selectable (1 or 2 bits).■ Transmission SpeedMaximum number of bits to be transmitted per second. Expressed in bps (bits persecond).■ Optical Interface Communications RangeThe optical interface's maximum effective range is 80 cm (31.5 in.) with the IR beamwithin a 10˚ angle of divergence.■ Switching Time between Sending and Receiving on Optical InterfaceThe optical interface should satisfy the following requirements in switching be-tween sending and receiving:(1) Within 10 ms from completion of sending, the optical interface should becomeready to receive.(2) After 10 ms or more from completion of receiving, the optical interface shouldstart sending.300, 600, 1200, 2400, 4800, 9600,19200, 38400, 57600, or 115200 bpsJIS 7- or 8-bit codesStart-stopLSB (Least significant bit) firstNone Even, odd, or none