Electromagnetic Flowmeter M-910
34
Operation manual
6 System control
The flowmeter includes serial lines RS232 and RS485. RS232 connector is located behind the front panel. RS485
terminals are behind the back panel. For the remote control to work properly, bus parameters must be set in the
setup menu. Address and baud rate are important for RS485 bus. Communication parameters are fixed for RS232
bus.
6.1 RS485 bus properties
To transfer the data using RS485 bus, 8N1 data format is used, i.e. each data word includes 8 bits, no parity and
one stop bit. The communication speed can be set using the system menu. Available values: 1200, 2400, 4800,
9600 and 19200 Bd. Each flowmeter has it’s own RS485 address. Range of these addresses is from 0 to 255.
6.2 RS232 bus properties
To transfer the data using RS232 bus, 8N1 data format is used, i.e. each data word includes 8 bits, no parity and
one stop bit. Communication speed 1200 Bd is fixed.
6.3 Command syntax
Communication between flowmeter and computer consists of a flow of periodically alternating commands type
command-response or query-response. Command is always a text followed by parameter and ended by control sign
<cr>. Response is always ended with control sign <cr>.
Commands described in this chapter can be issued through both buses (RS485 and RS232). The only difference is,
that before all commands for RS485 bus is identification in form “#00”. Where ‘#’ is the command prefix and “00”
is flowmeters address 0 in hexadecimal form. For flowmeter with address 1 it’s identification is “#01”. Flowmeter
answers are prefix in form “>00” for flowmeter 0, “>01” for flowmeter 1 etc.
Syntax description
<DNPD> = Decimal Numeric Program Data, this format is used to express decimal number with or without the
exponent.
<CPD> =
Character Program Data. Usually, it represents a group of alternative character parameters. e.g. {0 | 1
| 2 | 3}.
? =
A flag indicating a request for the value of the parameter specified by the command. No other
parameter than the question mark can be used.
(?) =
A flag indicating a request for the parameter specified by the command. This command permits a
value to be set as well as requested.
<cr> =
carriage return. ASCII code 13. This code executes the command or query.