The TMCM-1613-RS232 circuit offers the possibility to use standard RS232 signals for controlling the TMCM-1613 or even simple UART TTL (+5V) signals.

Reference Design TMCM-1613-RS232

The TMCM-1631 offers no dedicated serial interface for communication. Instead, the optically isolated digital input DIN0 of the I/O connector is used for receiving commands and the digital output DOUT0 on the same connector is used for transmission of the reply. The serial interface uses the standard TMCL protocol (9Bytes command and receive datagrams) with 9600bps, one stop bit and no parity as default communication parameters. In order to activate the serial interface, a voltage of at least 15V has to be applied to AIN0 of the I/O connector at power-up of the TMCM-1613. The regular voltage range of the AIN0 input is 0 .. 10V - so, a level of 15V or above can be clearly distinguished from normal use of the analog input by the TMCM-1613.

The TMCM-1613-USB interface converter is available for the TMCM-1613 which offers USB connection and does the required signal level adaptation and generates the required switching voltage from USB supply. In addition, it offers electrical isolation between USB and the TMCM-1613 for all signals. Nevertheless, this converter is not always appropriate - especially in case the TMCM-1613 is embedded in a setup without a standard PC and serial communication for control is required.

TMCM-1613 with RS232

Using standard RS232 signals for controlling the TMCM-1613

The TMCM-1613-RS232 circuit offers the possibility to use standard RS232 signals for controlling the TMCM-1613 or even simple UART TTL (+5V) signals. Nevertheless, please note that the circuit does not include isolation of the signals and therefore, care has to be taken in case the TMCM-1613-REC is used with an option for reverse polarity supply.

A few notes on the TMCM-1613-RS232 circuit itself: Connector X1 (D-SUB 9pin female) offers standard RS232 signals and pin assignment whereas connector X3 contains all the signals that should be connected to the TMCM-1613. The transmit signal TXD either coming directly from a UART or as output of the RS232 transceiver (IC3) is adjusted using the two MOSFET transistors T1 and T2 in order to be able to drive the input DIN0 of the optocoupler integrated into the TMCM-1613. The receive signal circuit includes a pull-up to +24V (R2||R4) for generating the high switching voltage at AIN0 and the inverter and level adjustment circuit around transistor T3 for generating +5V TTL compatible UART signals. Please be sure to connect GND between the TMCM-1613-RS232 circuit and the TMCM-1613 (required for AIN0).

TMCM-1613-RS232 Schema


For using the RS232 input either two jumpers should be closed (J1, connect 1-2 and 3-4) or resistors R7 and R9 should be assembled instead of the jumper grid. For direct UART connection both jumpers should be removed, R7 and R9 not installed and UART signals taken resp. injected at J1 / Pin2 and Pin4.

Visit the TMCM-1613 product page.



TMCM-1613-RS232-ASST_V10.pdf 15 KBNov 8, 2017 4:29 PM
TMCM-1613-RS232-SCH_V10.pdf 27 KBNov 8, 2017 4:29 PM 26 KBNov 8, 2017 4:29 PM
TMCM-1613-RS232_V10.brd 81 KBNov 8, 2017 4:29 PM
TMCM-1613-RS232-BOM_V10.csv 2.4 KBNov 8, 2017 4:29 PM